Grade 10 Physical Sciences - Physics - Chemistry - Noted Summaries 2023 PDF

Physical science Terminology Finance Skills : introduction SCIENTIFIC NOTATION MULTIPLICATION x * DIVISION÷ Let's see: W W W always requires one significant digit before the comma, but not zero. Comma shift left = positive exponent (value gets bigger) Commas fringe to the right = negative exponent (value gets smaller) 5 × 103 × 2 × 104 MULTIPLICATION =(5 × 2) × 10(3+4) (𝑎𝑛 )(𝑎𝑚 ) = 𝑎𝑛+𝑚 =10 × 107 ALSO CALLED THE 10TH MAGNOTATION W Express numbers as a product of 2 numbers : [𝑁 × 10𝑛 ] N = number term [any number between 1 & 9,999…] n = positive / negative number 3 5 × 10 ÷ 2 × 10 4 =1 × 108 SHARING =(5 ÷ 2) × 10(3−4) (𝑎𝑛 ) = 𝑎𝑛−𝑚 𝑚 (𝑎 ) =2,5 × 10−1 =0,25 ADD + * SUBTRACT W Step 1 :REDUCE all the numbers to the SAME power of 10 [same exponent] W Step 2 :number terms added / subtracted POWERS [OF NUMBERS] (𝑎𝑛 )𝑚 = 𝑎𝑛𝑚 5 × 105 + 2 × 104 (5 × 103 )2 =50 × 104 + 2 × 104 =52 × 10(3 ×2) = 52 × 104 = 25 × 106 =5,2 × 105 =2,5 × 107 2© Noted Summaries [Grade 10 Physical Sciences] PHYSICS → raise numerical term to indicated power & multiply exponent by indicated power www.notedsummaries.co.za SCIENTIFIC NOTATION ROOTS OF EXPONENTS W Step 1 :Rewrite number so that it has an even exponent W Step 2 :Find square root of number term + divide exponent by 2 (get answer) √3,6 × 103 √5,3 × 107 =√36 × 102 =√53 × 106 = √36 × 10(2÷2) = √53 × 10(6÷2) = = 606 × 10 =7,3 × 103 ON YOUR POCKET COMPUTER →to type a number in scientific notation, use the [older model calculators > ] test for numbers to the 10th power FOR EXAMPLE: W W 6 × 103 > > 6000 3 −4 6 × 10 × 3,5 × 10 > > 2.1 3© Noted Summaries [Grade 10 Physical Sciences] PHYSICS LENGTH / DISTANCES Neutron or proton radius 10−15 m Atom 10−10 m Virus 10−7 m Sheet of paper 10−4 m Finger width 10−2 m Length of football field 102 m Height of Everest 104 m Earth's circumference 107 m Earth→Sun 1011 m Distance to nearest star 1016 m Nearest galaxy 1022 m Farthest visible galaxy 1026 m TIME INTERVALS Lifetime (very unstable particle) 10−23 s Lifespan (radioactive elements) 10−22 s to s1028 Lifetime (muon) 10−6 s Time between human heartbeats 100 s = 1 s One day 105 s One year 3 × 107 s Human life 2 × 109 s Length of recorded history 1011 s People on earth 1014 s Life on earth 1017 s Age of universe 1018 s COMPARATIVE MASSES Electron 10−30 kg Proton / Neutron 10−27 kg DNA molecule 10−17 kg Bacteria 10−15 kg Mosquito 10−5 kg Plum 10−1 kg Person 102 kg Ship 108 kg Earth 6 × 10−24 kg Sun 2 × 1030 kg Star system 1041 kg www.notedsummaries.co.za CONVERSION [UNITS] SI- SYSTEM We now need a conversion factor: W Conversion factor > expresses the equivalence of a dimension in 2 different units teragigamegakilohectodecadesi senti military micro nano pico femto- CONVERSION SYMBOLS T G m k h da / D d c m 𝜇 a p f 1012 109 106 103 = 1 000 102 = 100 101 = 10 10−1 = 0,1 10−2 = 0,01 10−3 = 0,001 10−6 10−9 10−12 10−15 DIMENSIONAL ANALYSIS → problem solving method that uses the fact that any number or expression can be multiplied by one without changing its value → indicate WHICH NUMBER we need to multiply / divide BV by: Convert 60 cm to m (100cm = 1m) Step 1 : Write the CONVERSION FACTOR as a FRACTION 𝟏𝒎 𝟏𝟎𝟎 𝒄𝒎 Step 2 : Multiply the factor by the value to be converted Step 3 : Treat the units as numbers when multiplying fractions 4© Noted Summaries [Grade 10 Physical Sciences] PHYSICS →Système International d'Unités [international system of units > measurement] 7 BASIC units: 1. Length (distance) in meters (m) 2. Time (seconds) (s) 3. Mass (kilogram) (kg) 4. Electric current in amperes (A) 5. Temperature in Kelvin (K) 6. Luminous intensity in candela (cd) 7. Amount of matter in moles (moles) AMOUNT Position Distance Displacement Acceleration Starting velocity Terminal velocity Average speed Mass Weight Gravitational acceleration Potential energy Kinetic energy Height Frequency Period Wave speed Wavelength Tension Electric charge Electric current Resistance SYMBOL x D ∆x A 𝑣𝑖 or u 𝑣𝑓 or f f m w g 𝐸𝑝 𝐸𝑘 h f T f 𝜆 Q Q I R SI UNIT meter (m) meter (m) meter (m) Meters per second squared (𝑚 ∙ 𝑠 −2) Meters per second (𝑚 ∙ 𝑠 −1 ) Meters per second (𝑚 ∙ 𝑠 −1 ) Meters per second (𝑚 ∙ 𝑠 −1 ) Kilogram (kg) Newton (N) Meters per second squared (𝑚 ∙ 𝑠 −2) Joule (J) Joule (J) meter (m) Hertz (Hz) Seconds (s) Meters per second (𝑚 ∙ 𝑠 −1 ) meter (m) Volts (V) Coulomb (C) Amps (A) Ohm (Ω) www.notedsummaries.co.za CHANGE SUBJECT [FORMULA] CONVERSION [UNITS] TEMPERATURE →measured with THERMOMETER 3 temperature scales: REDIRECTED : °C→K (kelvin) 𝑻 = 𝒕 + 𝟐𝟕𝟑 1. Celsius (°C) 2. Fahrenheit (°F) 3. Kelvin (K) T (temperature > Kelvin) t (temperature > °C) K (kelvin)→°C W Step 1 : Move terms with the unknown (variable / symbol) to the LEFT SIDE & remove unknown terms on the right (additive inverse) W Step 2 : move all CONSTANT terms to the RIGHT SIDE (remove constants on the left by additive inverse) W Step 3 : simplify both sides W Step 4 : divide both sides by the coefficient of the variable 𝒕 = 𝑻 − 𝟐𝟕𝟑 LENGTH 𝑣𝑓 = 𝑣𝑖 + 𝑎∆𝑡 calculate acceleration (a) Step 1 : 𝑣𝑓 − 𝑎∆𝑡 = 𝑣𝑖 + 𝑎∆𝑡 − 𝑎∆𝑡 Step 2 : 𝑣𝑓 − 𝑎∆𝑡 − 𝑣𝑓 = 𝑣𝑖 − 𝑣𝑓 + 𝑎∆𝑡 − 𝑎∆𝑡 PRESSURE → PRESSURE = the force per unit area applied to a surface →( 𝑁 ∙ 𝑚−2 ) →PASCAL (Pa) →1 Pa = 1 𝑁 ∙ 𝑚−2 Step 3 : − 𝑎∆𝑡 = 𝑣𝑖 − 𝑣𝑓 [We now want to GET the equation POSITIVE > now multiply by -1 throughout]→ 𝑎∆𝑡 = 𝑣𝑓 − 𝑣𝑖 REDIRECTED : Step 4 : Dad (Pascal)→kPa (kilopascal) 𝑣𝑓 − 𝑣𝑖 𝑎∆𝑡 = ∆𝑡 ∆𝑡 𝑣𝑓 − 𝑣𝑖 ∴𝑎= ∆𝑡 1000 Pa = 1 kPa →1 atm (atmosphere) = 101.3 kPa (standard pressure) →1 bar = 100 kPa 5© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za BASIC TRIGONOMETRY TEMPO →rate = change per SECOND DRIVING →amount of energy delivered per unit time Power (watts) = energy (joule) time (sekondes) ACCELERATION →rate of change in velocity Acceleration (𝑚 ∙ 𝑠 −2) = change in velocity (m∙s−1 ) time (s) REACTION RATE →change in concentration of a reagent per unit time PROPORTION [∝] Let's see [PROPORTION]: DIRECT PROPORTION DIRECT PROPORTION →increase in independent quantity (𝑥) leads to a constant increase in the dependent quantity (𝑦) 𝒑 [𝒑𝒓𝒆𝒔𝒔𝒖𝒓𝒆 (𝒑) ∝ 𝒕𝒆𝒎𝒑𝒆𝒓𝒂𝒕𝒖𝒓𝒆 (𝑻), = 𝒌] 𝑻 𝑦 [𝑦 ∝ 𝑥, = 𝑘 𝑎𝑛𝑑 𝑦 = 𝑘𝑥] 𝑥 INVERSE PROPORTION →increase in independent quantity () leads to a decrease in the dependent quantity ()𝑥𝑦 [𝑦 ∝ 1 𝑥 INVERSE PROPORTION [𝒑𝒓𝒆𝒔𝒔𝒖𝒓𝒆 (𝒑) ∝ 𝟏 𝒗𝒐𝒍𝒖𝒎𝒆 (𝑽) , 𝒑𝑽 = 𝒌] 𝑘 , 𝑥𝑦 = 𝑘 𝑎𝑛𝑑 𝑦 = ] 𝑥 6© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za TRANSVERSAL PULSE PULSE → Single disturbance (effect of vibration) moving from one point to the next in a medium (spring or string) Principle of Superposition: W The joint response at a given place and time caused by 2 or more stimuli is the algebraic sum of the displacements / responses of each individual pulse / stimuli at that moment Pulse = has an AMPLITUDE & a PULSE LENGTH but NO FREQUENCY (occurs only once) TRANSVERSAL PULSE : → Pulse whose particles of the medium's deviation are perpendicular (at right angles) to the pulse's direction of movement / forward direction AMPLITUDE → maximum displacement (maximum disturbance) of a particle in a medium from its rest position (equilibrium position) SUPERPOSITION OF PULSES Superposition = when 2 pulses meet + occupy the same space at the same time → pulses combine & resultant displacement = sum of displacements of individual pulses 7© Noted Summaries [Grade 10 Physical Sciences] PHYSICS INTERVENTION INTERVENTION : → when two or more pulses (or waves) interact in the same space at the same time [2 pulses > same amplitude but ONE a CREST & ONE a Trough = cancel each other out = no movement→ DESTRUCTIVE INTERFERENCE] [2 crests / 2 troughs meet > reinforce each other & total amplitude = SUM OF THE INDIVIDUAL WAVES→ CONSTRUCTIVE INTERFERENCE] www.notedsummaries.co.za WAVES INTERVENTION TRANSVERSE WAVE : → Wave in which the disturbance of the medium is perpendicular to the direction of propagation of the wave → succession of transverse pulses WAVE: →oscillation / disturbance in which energy is carried away from the point of disturbance [regular succession of pulses] Amplitude > maximum distance of the wave from its resting position [measured in meters (m)] CONSTRUCTIVE INTERFERENCE →when two pulses meet on the same side of the rest position. They reinforce each other to cause a higher pulse, ie with a larger amplitude. After constructive interference, the two pulses (with their original amplitude) continue in their original direction Crest > The highest point of the waves DESTRUCTIVE INTERFERENCE →when two pulses meet on opposite sides of the resting position. They weaken each other to cause a lower pulse, ie with a smaller amplitude, or even for a moment no pulse. After destructive interference, the pulses move (with original amplitude) in the original directions of movement Wavelength > The distance between two peaks or two troughs and is measured in meters (m). troughs >The lowest points of the waves [SYMBOL :𝝀] 8© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za IN PHASE & OUT OF PHASE IN PHASE OUT OF PHASE → Two points on a wave when they are moving in the same direction and at the same speed and have the same displacement from rest [crests & troughs in line] → Two points on a wave if they move in such a way that they reach a position at different times [crests of one wave and troughs of another wave correspond] WAVE SPEED WAVE SPEED: → distance that the wave (or crest of the wave) travels in one second and is measured in meters per second → speed at which a wave moves forward → influenced by: material, density & temperature ∆𝑥 𝑣= ∆𝑡 distance (m) Wave speed = time (s) THE PENDULUM [VIBRATION] 𝜆 𝑣= 𝑇 wave length (m) Frequency (f) > number of whole waves / vibrations that pass a fixed point in one second and become in hertz (Hz) measured Wave speed = Period (T) [vibration] > the time it takes to complete one complete wave / vibration (whole wave) and becomes in seconds (s) measured 9© Noted Summaries [Grade 10 Physical Sciences] PHYSICS (𝑚 ∙ 𝑠 −1 ) period (s) Wave Speed = Frequency (Hz) x Wavelength (m) 𝑣=𝑓 × 𝜆 www.notedsummaries.co.za LONGITUDINAL WAVES LONGITUDINAL WAVE: → Wave where the disturbance (displacement) of the medium is parallel to the direction of propagation of the wave WAVE SPEED> Speed at which each compaction moves [equal to the product of the wavelength and frequency] 𝒗 = 𝒇𝝀 SOUND WAVES = LONGITUDINAL WAVES Frequency (f) > number of compressions that pass a point in one second Compression > parts where the coils of the spring are close together (bundled together). Period (T) > time taken by one full wavelength to pass a given point 𝑻= 𝟏 𝟏 𝐨𝐫 𝒇 = 𝒇 𝒇𝑻 Wavelength > distance between the center of one compaction and the center of a next compaction [SYMBOL :𝝀] Dilution / Decompression > parts the coils of the spring are further apart (stretched). Amplitude > maximum displacement of the particles from their rest position [measured in meters] 10© Noted Summaries [Grade 10 Physical Sciences] PHYSICS Sound waves = longitudinal waves [vibration = parallel to direction of propagation + causes particles of the medium to become compacted + thinned = pressure changes Sound waves = pressure waves > transfer energy & move particles of a material [magnetic wave] SPEED OF SOUND IN DIFFERENT MATERIALS [20°C + 1 ATMOSPHERE] Air (0°C) 331 𝑚 ∙ 𝑠 −1 Air (20°C0 343 𝑚 ∙ 𝑠 −1 Hydrogen 1,300 𝑚 ∙ 𝑠 −1 Water 1 440 𝑚 ∙ 𝑠 −1 Sea water 1,560 𝑚 ∙ 𝑠 −1 Iron and steel ≈5,000 𝑚 ∙ 𝑠 −1 Glass ≈4,500 𝑚 ∙ 𝑠 −1 Aluminium ≈5,100 𝑚 ∙ 𝑠 −1 → move faster + further through solid matter than through air [pressure waves of sound propagate better > molecules spaced closer together] → speed of sound >  temperature www.notedsummaries.co.za SOUND IMPORTANT!: → SOUND WAVES = LONGITUDINAL WAVES LOUDNESS [SOUNDS] INTENSITY OF THE WAVE → measure of the amount of energy carried by the wave → distance between 2 crests = time it takes for a full oscillation [oscillation period] → the more () oscillations in one second = the higher () the 1 frequency [f𝑟𝑒𝑘𝑤𝑒𝑛𝑠𝑖𝑒 = 𝑝𝑒𝑟𝑖𝑜𝑑𝑒 ] → height of a crest = amplitude of oscillation [ crests =  amplitude] AMPLITUDE: maximum distance the vibrating particles move from rest position [→ measure of the PRESSURE CHANGES caused by the vibrating particles]  amplitudes = louder sounds SOFT NOTE HARD NOTE PITCH → refers to how high / low a sound is [depends on FREQUENCY]  FREQUENCY =  PITCH LOW PITCH HIGH PITCH HUMAN AUDIENCE SCOPE : human ear hears sounds with a frequency between 20Hz and 20,000 Hz [hears best between : 1,000 & 5,000 Hz] 11© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za QUALITY OF SOUND ** Tuning fork = produces a note of ONE FREQUENCY W Pure sound & provides sine curve > oscilloscope [regular pressure waves > enters the ear = vibrates ear drum] W Brain = interprets regular vibrations as musical sounds SOUND > mixture of unrelated frequencies = doesn't sound musical [inharmonic] ULTRASOUND FREQUENCIES ABOVE 20,000 Hz (20 kHz) → cannot be heard by human ear ** Bats = use ultrasound to find their way in the dark at night > emit ultrasonic waves > reflected from other insects / objects [parabolic ears > parabolic reflectors → reflects all sound to focal point = concentrated / amplified] MEDICAL USE Ultrasound wave travels inside an object → part of the wave = reflected and part = refracted → sonars > check health of babies [use sonars] → detecting blockages & other problems with internal organs [tumors & gallstones > destroyed, measuring blood flow through organs, veins & arteries & kidney treatment] 12© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za ELECTROMAGNETIC RADIATION ELECTROMAGNETIC WAVES: → due to the acceleration of electric charges and is characterized by altered electric fields induced perpendicular to altered magnetic fields → direction of propagation is perpendicular to both the electric and magnetic fields →electromagnetic waves are caused without a material medium + can be propagated in a vacuum LIGHT : ELECTROMAGNETIC RADIATION DIFFRACTION INTERFERENCE POLARIZATION → bending or spreading of waves around the edges of a barrier or opening → when two or more wave fronts pass over each other and are superimposed on each other, so that they form higher crests and deeper troughs, or partially or totally cancel each other out → extinction of waves in that the wave only vibrates in one particular plane. Only transverse waves can be polarized LIGHT : PHOTOELECTRIC EFFECT [LINE SPECTRA] → Light acts as a stream of particles DUAL NATURE OF ELECTROMAGNETIC RADIATION: WAVE-PARTICLE DUALITY Particle model → when light acts on matter [photoelectric effect + line spectra] Wave model → when the wavelength of the light is similar to the dimensions of the object on which it acts [diffraction & interference] [electromagnetic radiation = transverse] 13© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za NATURE : ELECTROMAGNETIC RADIATION → ELECTROMAGNETIC RADIATION = electric + magnetic fields ELECTRIC FIELD : oscillates in one plane + produces a magnetic field > oscillates with another plane RECTANGULAR [perpendicular] OSCILLATING MAGNETIC FIELD : produces oscillating electric field Electric & magnetic field = oscillate in phase & AT RIGHT ANGLE with each other [fields = perpendicular to direction of propagation] ELECTROMAGNETIC SPECTRUM SPEED : 𝑐 = 3 × 108 𝑚 ∙ 𝑠−1 → different frequencies, wavelengths & energy [HOW DO WE CALCULATE THIS?] = WAVE EQUATION 𝑐 = 𝑓𝜆 ELECTROMAGNETIC SPECTRUM: ELECTROMAGNETIC RADIATION = TRANSVERSAL WAVES → the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies [RADIO WAVES = longest wave spring ( frequency)] [GAMMA RAY = shortest wavelength ( frequency)] ELECTROMAGNETIC WAVES (SPEED > EMPTY SPACE) = SPEED OF LIGHT → 3 × 108 𝑚 ∙ 𝑠−1 Waves = contain energy = absorbed by material > INTERNAL ENERGY  SHORTER WAVELENGTH () = MORE ENERGY () 14© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za HIGH ENERGY RAYS : X-RAYS VISIBLE LIGHT → visible spectrum: violet, indigo, blue, green, yellow, orange & red → 0.01nm to 10nm RED : longest wavelength [fast] VIOLET : shortest wavelength → when fast moving electrons are brought to a sudden stop [metal target] > energy is converted into electromagnetic energy (moving more slowly) → sunlight = light particles = PHOTONS [electromagnetic radiation = consists of PHOTONS] INFRARED → not hot [remote control devices] → warm [heaters / fires / sun] USES OF X-RAYS: Z Penetrate solid objects > doctors + dentists : use images to see what's going on inside our bodies Z Security checkpoints at airports > identify objects in luggage Z Chemists & geologists : atomic structure of crystalline solids [X-RAY CRYSTALLOGRAPHY] USES OF INFRARED LIGHT: Z Z Z Z Conventional oven [heating element] Photographers with NIGHT VISION CAMERAS [enhance available light] Thermal imaging [infrared cameras] Tracking Devices [Guided Missile Technology / Heat Guided Missiles] ULTRAVIOLET → short wavelengths → makes the skin BROWN > dark pigment : melanin [absorbs ultraviolet + protects underlying layers of living skin cells] HIGH ENERGY RAYS : GAMMA RAYS → shortest wavelength [travels through most matter] & MOST ENERGY → radiation : causes mutations, chromosome change, cancer & cell death USES OF GAMMA RAYS: Z High doses : destroy cancer cells in tumours [radiotherapy / radiation therapy] Z kill bacteria (sterilize) Z Food > irradiated : keeps fresh longer USES OF ULTRAVIOLET RAYS / LIGHT: Z “black light” > lamps in theater lighting / attract insects > high voltage wires Z Kill microbes > sterilize Z Forensic scientists: clues at crime scenes Z Fluorescent light tubes (filled with mercury vapor & powder coated) Z Detergents with chemicals > optical brighteners > make clothes look "whiter than white". 15© Noted Summaries [Grade 10 Physical Sciences] PHYSICS PENETRATION CAPACITY: → Waves with high frequencies (X-rays & Gamma rays) = can penetrate through solids → Waves with low frequencies = CANNOT penetrate solids www.notedsummaries.co.za LOW ENERGY RAYS : MICROWAVES → electromagnetic waves with wavelengths ranging from 1m to 1mm USES OF GAMMA RAYS: Z Microwave ovens: 12 cm of energy radiated to food [water molecule in the food ROTATE > friction = heats surrounding food molecules] Z Satellite communication systems Z Speed trap devices [radar meter > radar signal] CELL PHONE RADIATION: → Mobile phones = electromagnetic radiation (microwave range) = HARMFUL TO HUMAN HEALTH LOW ENERGY RAYS : RADIO WAVES ELECTROMAGNETIC RADIATION : PARTICLE NATURE PHOTON: → basic particle of light & other forms of electromagnetic radiation [“packet of energy”] → energy = quantized & PHOTON = quantum energy → by charged particles emitted & absorbed [carriers of energy] PLANCK-EINSTEIN EQUATION :  frequency of radiation =  energy in the proton 𝐸 ∝ 𝑓; 𝐸 = ℎ𝑓 E = energy of photon F = frequency H = Planck's constant = 6,63 × 10−34 𝐽 ∙ 𝑠 → LONGEST WAVELENGTHS [+-3m] → NATURAL RADIO WAVES : lightning / stars & galaxies Medium & long (low + medium frequency) Surface waves (follows curvature of Earth) Weaker > lower atmosphere reflected Can't over long distances Military communications Short waves (frequency) Space waves / ionospheric waves (reflection from upper layers of atmosphere) Very long distances Amateur radio operators + sea communications & aircraft Very High Frequency (VHF) & Ultra High (UHF) Propagated directly between antennae (visible to each other). Most common way to transmit TV and radio signals Through the atmosphere & reflected back to earth via satellite satellite communications 16© Noted Summaries [Grade 10 Physical Sciences] PHYSICS Frequency + wavelength (electromagnetic wave) > relation to SPEED of electromagnetic radiation [equation 𝑐 = 𝑓𝜆] c = speed of electromagnetic radiation = 3 × 108 𝑚 ∙ 𝑠 −1 f = frequency (Hz) λ= wavelength ℎ𝑐 𝐸 = ℎ. 𝑓 = 𝜆 www.notedsummaries.co.za MAGNETISM MAGNETS CONSIST OF FERROMAGNETIC SUBSTANCES: Cobalt (Co) Nickel (Ni) Iron (Fe) Magnetite (Fe O ) Hematite (Fe O ) FIELD LINES → shows a magnet's magnetic field → direction = compass needle > extends from magnet's north pole to south pole [indicated by ARROWS] THE CLOSER THE FIELD LINES TO EACH OTHER = THE STRONGER THE FIELD MAGNETIC FIELD MAGNETIC FIELD: →area in SPACE around a magnet where other magnets / ferromagnetic materials experience a force WITHOUT PHYSICAL CONTACT MAGNETIC POLES Magnet = 2 poles > ALWAYS DIFFERENT [→ points where the magnetism is the STRONGEST] THE EARTH'S MAGNETIC FIELD →NOT exactly located at geographic poles! 24° west of true NORTH [measurement deviation] SIMILAR POLES = push each other off UNEQUAL POLES = attract each other 17© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za EFFECT: EARTH'S MAGNETIC FIELD COMPASS → instrument for finding North → COMPASS NEEDLE = small magnet that aligns itself with the Earth's magnetic field MAGNETIC STORMS → temporary disturbance of the Earth's magnetosphere [space around the Earth > magnetic field] caused by a solar wind shock wave [plasma cloud > charged particles with high energy] and/or cloud of magnetic field interacting with the Earth's magnetic field → compression on the day side & long magnetotail [extended field lines] on the night side → 2 – 4 days later > solar wind hits Earth's surface = MAGNETIC STORM FORMATION OF AURORAS → bright glow that can be seen in the night sky of the polar regions [NORTHERN LIGHTS] → peak time of 11-year sunspot cycle [September to October and March to April] → when charged particles are caught in the solar wind and spiral down the Earth's field lines towards the poles [reach ionosphere = collide with gases > charged gas atoms glow + provide colored red, green, blue & violet] SOUTH POLE > aurora australis NORTH POLE > aurora borealis → Earth's magnetic North Pole = determined by compass > always points to SOUTH POLE of Earth's magnetic field EARTH > MAGNETIC SOUTH POLE = CANADA EARTH > MAGNETIC NORTH POLE = ANTARCTIC EARTH : Z Arctic region = magnetic South Pole, geographic North Pole Z Antarctic region = magnetic North Pole, geographic South Pole EFFECTS: Z SPACE WEATHER : changed conditions in space Z Magnetic storms = affect satellites (communication, radio, GPS) Z Rapidly changing Aurora following a Magnetic storm = induces electrical storms in long conductors Z Bright Aurora = tremendous power + energies in the atmosphere 18© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za ELECTROSTATICS ELECTROSTATICS: →study of static electricity, ie the study of charges at rest [STATIONARY] ELECTRIC CHARGE Z Frictional forces between certain materials allows ELECTRONS to move from atoms of one material to the atoms of another material Z Only electrons can be transferred from an atom or lost from an atom Z ELECTRONS = NEGATIVE = SUB-ATOMIC PARTICLES Z Material that loses electrons becomes positively charged [potential energy] Z If the charges are the same, they repel each other Z If the charges are different, they attract each other 6 positive charges and 6 negative charges [ 6 + (-6) = 0] 8 positive charges and 6 negative charges [ 8 + (-6) = 2] There is no net charge. Net charge is therefore +2 Object = neutral Object = POSITIVELY CHARGED 6 positive charges and 9 negative charges [ 6 + (-9) = 3] Net charge is therefore -3 Object = NEGATIVELY CHARGED 19© Noted Summaries [Grade 10 Physical Sciences] PHYSICS ELECTRIC CHARGES : FORCE EXERCISED SIMILAR CHARGES = push each other off UNEQUAL CHARGES = attract each other POLARIZATION POLARIZATION: → attraction between charged and uncharged objects (neutral insulator) → gives a negative charged pole + positive charged pole www.notedsummaries.co.za CONSERVATION OF CHARGE LAW OF CONSERVATION OF ELECTRIC CHARGE: → net charge of an isolated system remains constant during any physical process → Charge can neither be created nor destroyed, it can only be transferred therefore, the algebraic sum of the charges in an isolated system remains constant FORMULA TO CALCULATE LOAD ON MATERIAL [AFTER SEPARATION] 𝑄= 𝑄1 + 𝑄2 2 CHARGE QUANTIZATION PRINCIPLE OF CHARGE QUANTIZATION.: → An object has an electric charge which is an integer multiple (of1,6 × 10−19 𝐶 ) of the elementary charge (electron charge) 𝑸 = 𝒏𝒒𝒆 Q = charge n = integer 𝒒𝒆 = charge on one electron IMPORTANT!: ELEMENTARY CHARGE ON ELECTRON = -1,6 × 10−19 𝐶 ELEMENTARY CHARGE ON PROTON = + 1,6 × 10−19 𝐶 E.g. : REMEMBER : [METRIC MULTIPLES p.4] 1 𝜇𝐶 = 1 × 10 −6 𝐶 𝑄= (+2 𝑛𝐶) + (−5 𝑛𝐶) 2 = -1.5 nC 20© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za ELECTRIC CIRCUITS POTENTIAL DIFFERENCE & EMF EMF / P [electromagnetic force / pulses]: → amount of energy that the cell (or battery) is capable of imparting to 1 coulomb of charge passing through the cell (or battery). → potential difference measured across the terminals (poles) of the cell or battery as measured with a voltmeter when the cell or battery is not producing any electric current → determined by : size + chemical composition → indication of total amount of AVAILABLE ENERGY ELECTRIC CURRENT ELECTRIC CURRENT → measure of the RATE AT WHICH charge flows past a point / cross section of a conductor [PER SECOND] 1 coulomb charge (in one second) = current is one AMPERE 𝑐ℎ𝑎𝑟𝑔𝑒 (𝑐𝑜𝑢𝑙𝑢𝑚𝑏) 𝑠𝑡𝑟𝑒𝑎𝑚 (𝑎𝑚𝑝𝑒𝑟𝑒) = 𝑡𝑖𝑚𝑒 𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙(𝑠) 𝐼= 𝑄 ∆𝑡 POTENTIAL / POLAR VOLTAGE DIFFERENCE: → difference in electrical potential energy per unit charge (measured in Volts (V)) POTENTIAL DIFFERENCE < EMP EMF – pole voltage = internal voltage of battery MEASUREMENT: POTENTIAL DIFFERENCE > VOLTMETER [ALWAYS PARALLEL] > VOLT > (V) CURRENT > AMMETER [ALWAYS IN SERIES] > AMPERE (A) 21© Noted Summaries [Grade 10 Physical Sciences] PHYSICS 1 coulomb charge =𝑄 − 𝐼∆𝑡 [1 coulum passes any cross-section of a conductor in 1 second when a current of 1 ampere flows through the conductor] CURRENT: → flow of electrons [from positive to negative pole in a battery] > indicated by ARROWS on a circuit www.notedsummaries.co.za POWER CIRCUIT COMPONENTS DIRECTIONS OF CURRENT CONVENTIONAL CURRENT → flow of POSITIVE CHARGES → positive (+) to negative (-) TRUE CURRENT → flow of NEGATIVE CHARGES → negative (-) to positive (+) UNIT : Measured with : Volts (V) / Amps (A) Voltmeter / Ammeter Red contact point → connect to positive pole and Black contact point → at the negative pole. VOLTMETER : Possesses large resistance so that the current flows through the circuit and components and not through the voltmeter AMMETER : low resistance Symbols : Always connected in parallel Always connected in SERIES 22© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za RESISTANCE RESISTANCE (R) : → ratio of the potential difference (V) across an electrical component to the current (I) flowing through it → RESISTANCE TO THE FLOW OF ELECTRIC CURRENT (ELECTRONS)  resistance =  current  resistance =  current RESISTORS IN SERIES R ∶ R s = R1 + R 2 + R 3 I ∶ I1 = I2 V ∶ V𝑇 = V1 + V2 + V 3 → Total current voltage is equal to the sum total of the current voltages of the individual resistors → resistance  if more resistors are added → current is the same THROUGHOUT the circuit FACTORS AFFECTING RESISTANCE: Material of the conductor Length of the conductor Thickness of the conductor Temperature of the conductor RESISTORS IN PARALLEL R∶ 2 resistors in parallel: a short conductor has a low resistance a long conductor has a high resistance 1 1 1 1 = + + Rp R1 R 2 R 3 R𝑝 ∶ product R1 R 2 = sum R1 + R 2 a thick conductor lowers the resistance I ∶ It = I1 + I2 + I3 a thin conductor increases the resistance V ∶ V = V1 = V2 = V 3 = V 4 a high temperature has a high resistance a low temperature causes low resistance → Total Current Voltage / Potential Difference = CONSTANTLY THE SAME → resistance IS DIVIDED [PROPORTIONATELY] as more resistors are added → current is DIVIDED in the circuit [resistors] 23© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za 24© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za MECHANICS : VECTORS & SCALARS SCALAR PHYSICAL QUANTITY: → measure and describe physical properties of an object in an appropriate SI unit → possession in numerical value, and a physical unit of measure → CHARACTERISTICS OF AN OBJECT [Mass, volume, speed, velocity, acceleration, temperature] VECTORS VECTORS : → Physical quantities that possess magnitude, unit and direction [Direction must be defined!] SCALAR: →Physical quantities that possess only size (magnitude) and unit No direction is defined! CRITERION Time Distance Speed Temperature Mass Energy SYMBOL t d f T m E UNIT Seconds (s) meter (m) Meters per second Degrees Celsius (°C) / Kelvin (K) Kilogram (kg) kilojoule (kJ) Vectors are indicated by arrows Z The length of the arrow represents the magnitude of the vector Z the arrowhead represents the direction of the vector CRITERION Displacement Speed Acceleration Weight Force SYMBOL 𝑥 horizontal / vertical 𝑦 𝑣⃗ 𝑎 𝑔 𝐹 UNIT meter (𝑚) Meters per second(𝑚 ∙ 𝑠 −1) Meters per second²( 𝑚 ∙ 𝑠 −2) Newton (𝑁) Newton (𝑁) 25© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za PROPERTIES OF VECTORS MULTIPLICATION OF VECTORS BY SCALARS EQUALITY OF VECTORS → multiply VECTOR (V) by scalar (c) > c = positive constant [cV = same direction as V > magnitude of cV] 2 vectors are equal: same magnitude + direction (regardless of origin) THEREFORE: MULTIPLYING A VECTOR BY A SCALAR (-) : CHANGE THE SIZE OF THE VECTOR (factor c) [WITH CHANGE OF DIRECTION] THIS IS NOW THE OPPOSITE DIRECTION OF V NEGATIVE VECTORS vectors that have the same magnitude but act in the opposite direction BUT! No vector is ever negative in magnitude > the (-) only indicates the DIRECTION VECTORS : ADDITION AND SUBTRACTION ON A STRAIGHT LINE → COUNT TOGETHER : REMEMBER THE DIRECTION!!! Vectors to the right = POSITIVE; Vectors to the left = NEGATIVE MULTIPLICATION OF VECTORS BY SCALARS → multiply VECTOR (V) by scalar (c) > c = positive constant [cV = same direction as V > magnitude of cV] RESULTANT : addition / subtraction of magnitudes of vectors [single vector having the same effect as two or more vectors together] THEREFORE: MULTIPLYING A VECTOR BY A SCALAR (+) : CHANGE THE SIZE OF THE VECTOR (factor c) [no change of direction] 26© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za VECTORS AGAINST AN ANGLE VECTORS : ADDITION AND SUBTRACTION VECTORS AGAINST AN ANGLE METHOD 1 : TAIL AT HEAD METHOD → 2 vectors form an angle METHOD 2 : TAIL BY TAIL [PARALLELOGRAM] IMPORTANT! If the forces make an angle of 90° > use PYTHAGORAS! To calculate the resultant AND the direction of the resultant force Draw first vector (𝑉1 ) on diagram Draw (𝑉2 ) by placing its tail on the tip of (𝑉1 ) (REMEMBER THE RIGHT DIRECTION!!!) Connect with an arrow the tail of (𝑉1 ) with point of (𝑉2 ) = determine vector of the 2 vectors Draw first vector (𝑉1 ) on diagram Sign (𝑉2 ) AT SAME ORIGIN AS (𝑉1 ) Connect parallelogram > lines parallel to both vectors RESULTANT : common origin of vectors & finite CAN ALSO USE : POLY-METHOD → 3 / more vectors included [draw resultant from the tail of the first vector to the point of the last vector] 27© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za VECTORS AGAINST AN ANGLE METHOD 3 : ALGEBRAIC METHOD NET / RESULTANT VECTOR The net or resultant vector is obtained by adding all vectors together. 𝐹𝑥 𝑁𝑒𝑡𝑡𝑜 = 𝐹𝐿𝑒𝑓𝑡 + 𝐹𝑅𝑖𝑔ℎ𝑡 𝐹𝑦 𝑁𝑒𝑡𝑡𝑜 = 𝐹𝑈𝑝 + 𝐹𝐷𝑜𝑤𝑛 IMPORTANT! Take one direction (eg up and right) as positive; All vectors in that direction are positive and all vectors in the opposite direction are negative. VECTORS IN THE SAME DIRECTION: ∴𝐹𝑦 𝑁𝑒𝑡𝑡𝑜 = 𝐹𝑈𝑝 + (−𝐹𝐷𝑜𝑤𝑛) 𝐹𝑈𝑝 = 𝐹1 + 𝐹2 + 𝐹3 ∴𝐹𝑥 𝑁𝑒𝑡𝑡𝑜 = 𝐹𝑅𝑖𝑔ℎ𝑡 + (−𝐹𝐿𝑒𝑓𝑡) 𝐹𝐷𝑜𝑤𝑛 = 𝐹4 + 𝐹5 + 𝐹6 VECTORS IN OPPOSITE DIRECTION: 𝐹𝑌 = (𝐹1 + 𝐹2 + 𝐹3) − (𝐹4 + 𝐹5 + 𝐹6) All vectors in the same direction can be added together, while vectors in opposite directions are subtracted The maximum resultant vector that can be obtained is when two vectors work in exactly the same direction (0° with respect to each other).𝐹1 + 𝐹2 = 𝐹𝑀𝑎𝑥 𝑁𝑒𝑡𝑡𝑜 The minimum resultant vector that can be obtained is when two vectors work in exactly opposite directions (180° with respect to each other).𝐹1 − 𝐹2 = 𝐹𝑀𝑖𝑛 𝑁𝑒𝑡𝑡𝑜 28© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za MECHANICS : MOTION IN ONE DIMENSION ONE DIMENSIONAL MOVEMENT: → Movements along a straight line and can be either in one direction or in the opposite direction FRAMES OF REFERENCE → reference point (origin) combined with a set of directions - such as an axis system - which makes it possible to define the position of the object on any time strip POSITION→ 𝑥 → location where the object is (occupies) as observed from a reference point [positive / negative] DIRECTION → North-south direction [east-west = perpendicular to north-south (up-down)] → we need 3 COORDINATES DISTANCE + DISPLACEMENT DISTANCE (d)> measured in (m) → length of the path along which an object moves from its ORIGINAL POSITION [Scalar] DISPLACEMENT DISPLACEMENT : → change in position relative to the reference point [shortest possible distance between two points] → CHANGE OF POSITION of an object → distance travelled in a direction → straight line path between start & end point → vector ∆𝑥 / ∆𝑦 → positive / negative (neg. > opposite direction than positive displacement) → Cartesian coordinate system : > north = east+𝑦 + 𝑥 E.G : - 20 ms-1 East 30 N, 30° from North 9.8 ms-2 downward (toward the center of the Earth) 1,200 m, 25° to the horizontal 29© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za AVERAGE SPEED REDIRECTIONS SPEED : → measure : distance travelled during a specific time MEASURE: Distance between 2 points moved Duration of movement Constant (uniform) speed = Object travels an equal distance in equal amounts of time [magnitude and direction do not change] AVERAGE SPEED [SCALAR] : → distance travelled divided by the time taken to move / The distance traveled per time interval / The rate of change in distance average speed = distance travelled (d) time (∆t) VELOCITY EQUATION =km ∙ h−1 average velocity = AVERAGE SPEED (𝑣or𝑣⃗) displacement time 𝑣̅ = ∆𝑥 ∆𝑡 displacement = ave. velocity × time [∆𝑥 = 𝑣̅ ∆𝑡] AVERAGE SPEED [VECTOR] : → displacement (change in position) travelled divided by the time it takes / The displacement (change in position) per time interval / The rate of change in displacement average velocity = displacement time 𝑣= time = displacement ave. velocity ∆𝑡 = ∆𝑥 𝑣̅ ∆𝑥 ∆𝑡 30© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za “INSTANT”- ACCELERATION (𝑎) ACCELERATION [VECTOR] : → rate of change in velocity [magnitude, direction] → measured in : 𝑚 ∙ 𝑠 −2 (meters per second squared) change in velocity ∆v acceleration = a= time ∆t → positive / negative [ positive > faster forward + acceleration = positive] [ positive = initial velocity > final velocity = slow motion + acceleration = negative] BUT! Sometimes the formula can also look like this: a= 𝑣𝑓 −𝑣𝑖 ∆𝑡 or a = v−u ∆𝑡 𝑣𝑓 / 𝑣 = final velocity ; SPEED → speed of an object in a very short time interval (infinitely small-time interval) and is the same magnitude of the instantaneous velocity [SCALAR] SPEED → displacement (deflection in position, ∆𝑥) divided by an infinitesimally small (very short) time interval (∆𝑡 ~ 0) [VECTOR] INSTANTANEOUS SPEED = INSTANTANEOUS VELOCITY 𝑣𝑖 / 𝑢 = initial velocity 31© Noted Summaries [Grade 10 Physical Sciences] PHYSICS www.notedsummaries.co.za MECHANICS : DESCRIPTION OF MOTION REMEMBER!: → in terms of : acceleration & velocity [say whether it is + or –] GRAPHICS Straight line = object moving at a constant velocity > NOT ACCELERATING Slope = which object moves faster [steeper the slope =  speed] POSITION-TIME GRAPHS [ACCELERATED MOTION] ACCELERATION = SLOPE OF GRAPH IN WORDS MOVE FASTER MOVE SLOWER HOW TO CALCULATE VELOCITY FROM A POSITION-TIME GRAPH: Slope = 0 > distance does not change [SO velocity v=0] AND THE OBJECT IS STANDING STILL Slope SUDDENLY becomes negative > object moves back from where it came [velocity (v) becomes NEGATIVE] 32© Noted Summaries [Grade 10 Physical Sciences] PHYSICS 1. Identify straight portion of the graph 2. Draw horizontal & vertical lines > complete right triangle [ACCURACY!] 3. Calculate lengths of the sides (triangle) > vertical line = position change & horizontal line = time change 4. Divide vertical height by horizontal width = change in position divided by change in time www.notedsummaries.co.za SPEED-TIME AND SPEED-TIME GRAPHS CALCULATE : DISPLACEMENT [VELOCITY-TIME GRAPH] CALCULATE : ACCELERATION [VELOCITY-TIME GRAPH] Straight line = CONSTANT ACCELERATION CONSTANT SPEED: STEEPER SLOPE = acceleration CONSTANT VELOCITY > acceleration = 0 Negative slope = negative acceleration 33© Noted Summaries [Grade 10 Physical Sciences] PHYSICS DISPLACEMENT = AREA UNDER VELOCITY-TIME GRAPH www.notedsummaries.co.za STOPPING DISTANCE = THINKING DISTANCE + BRAKE DISTANCE ACCELERATION-TIME GRAPHS THINKING DISTANCE: > “REACTION DISTANCE” → distance the car moves before the brake is stepped on while the driver/brain is still reacting → HORIZONTAL LINE (-) : deceleration in a POSITIVE direction / acceleration in a NEGATIVE direction BRAKE DISTANCE: → distance travelled from the moment the brake is stepped on until the car comes to a stop BRAKING DISTANCE INCREASES FASTER AS THE CAR'S SPEED INCREASES OPERATION EQUATIONS OPERATION EQUATIONS : → set of equations that enable us to calculate the quantities involved when an object moves with a CONSTANT ACCELERATION 𝑣𝑓 = 𝑣𝑖 + 𝑎∆𝑡 𝑣 = 𝑢 + 𝑎∆𝑡 1 ∆𝑥 = 𝑣𝑖 ∆𝑡 + 𝑎∆𝑡² 2 1 𝑠 = 𝑢𝑡 + 𝑎𝑡² 2 𝑣𝑓 ² = 𝑣𝑖 ² + 2𝑎∆𝑥 𝑣² = 𝑢² + 2𝑎𝑠 𝑣𝑓 + 𝑣𝑖 ∆𝑥 = ∆𝑡 2 𝑢+ 𝑣 𝑠= 𝑡 2 34© Noted Summaries [Grade 10 Physical Sciences] PHYSICS HOW? [STEPS]: 1. Write down the given quantities + the quantity you want to calculate 2. Choose the equation that connects the quantities [equation with all the known EXCEPT unknown quantity] 3. Select a POSITIVE DIRECTION > positive magnitudes + quantities 4. Substitute values into the equation 5. Calculate the unknown quantity 6. Write down the DIRECTION of any VECTOR QUANTITY www.notedsummaries.co.za MECHANICS : ENERGY ENERGY = MEASURED IN Joules (J) BUT WHAT IS ENERGY? → ability to perform labor POTENTIAL ENERGY :𝐸𝑃 POTENTIAL ENERGY : [STORED ENERGY] → energy that an object has as a result of its position, condition, or shape GRAVITY = POTENTIAL ENERGY GRAVITATIONAL POTENTIAL ENERGY: → energy that an object has as a result of its position in a gravitational field relative to a certain reference point → STORED energy that objects have > position relative to another body with MASS 𝑔𝑟𝑎𝑣𝑖𝑡𝑎𝑡𝑖𝑜𝑛𝑎𝑙 𝑝𝑜𝑡𝑒𝑛𝑡𝑖𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 = 𝑤𝑒𝑖𝑔ℎ𝑡 × ℎ𝑒𝑖𝑔ℎ𝑡 𝐸 𝑃 = 𝑚𝑔ℎ m = mass of object g = gravitational acceleration [𝑔 = 9.8 𝑚 ∙ 𝑠 −2 ] h = height above earth surface 35© Noted Summaries [Grade 10 Physical Sciences] PHYSICS GRAVITY Gravitational field = Area or space around an object. Gravitational force (gravitational force) = The force of attraction that objects exert on each other due to their mass (Earth on all objects near its surface) Object moves UP =  gravitational potential energy Object moves DOWN (TO Earth) =  gravitational potential energy KINETIC ENERGY :𝐸𝐾 KINETIC ENERGY : [MOVING ENERGY] → energy that an object has as a result of its motion NET LABOUR (object) = CHANGE IN KINETIC ENERGY [LABOURENERGY PRINCIPLE] 𝑘𝑖𝑛𝑒𝑡𝑖𝑒𝑠𝑒 𝑒𝑛𝑒𝑟𝑔𝑖𝑒 = ½ × 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑜𝑏𝑗𝑒𝑐𝑡 × 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦² m = mass of object v = velocity 𝐸 𝐾 = ½ 𝑚𝑣² THE FASTER AN OBJECT MOVES =  KINETIC ENERGY www.notedsummaries.co.za MECHANICAL ENERGY :𝐸𝑀 = 𝐸𝑃 + 𝐸𝐾 MECHANICAL ENERGY : → Sum of the gravitational potential energy (Ep) and kinetic energy (Ek) of an object on a given time strip 𝐸𝑀 = 𝐸𝑃 + 𝐸𝐾 PRINCIPLE / LAW : CONSERVATION OF MECHANICAL ENERGY: The sum of gravitational potential energy and kinetic energy in an isolated system is constant LAW OF CONSERVATION OF ENERGY: Energy cannot be created / destroyed, CAN ONLY BE CONVERTED FROM ONE FORM TO ANOTHER Sources for the preparation of this document: GALILEO : EXPERIMENT [VERTICAL MOTION] Galileo believed that in the absence of resistance, objects would fall not depending on their weight, but on the time of fall. Galileo believed that a projectile is a combination of uniform motion in the horizontal direction and uniform accelerated motion in the vertical direction. 36© Noted Summaries [Grade 10 Physical Sciences] PHYSICS 2023-2024 ATP [EDUGOV] Grade 10 Physical Sciences [Study and Master Gr 10 Learner's Book] Quizlet Additional Notes Added notes by compiler www.notedsummaries.co.za Physical science MATTER + MATERIALS : CLASSIFICATION OF MATTER MATTER: → Anything that occupies space and has mass SUBSTANCE → matter that has a CONSTANT composition + particular properties [eg. water, table salt etc.] MATERIAL: → Substances composed of matter 3 categories : ELEMENTS, COMPOUNDS and MIXTURES PHYSICAL PROPERTIES OF MATERIALS Z Strength / ability to resist force Z Thermal conductivity [heat conduction] → Metals conduct heat and are thermal (heat) conductors. Non-metals such as → does not conduct heat well = thermal (heat) insulators Z Electrical conductivity → Metals are good electrical conductors. Materials that cannot conduct an electric current are called an electrical insulator Z Brittleness → Brittle materials break easily when bumped hard. Earthenware and cast iron are examples of brittle materials. Z Crushable / Spreadable → hammered or rolled into different shapes Z Stretchable → to thin wires > Copper = copper wire Z Magnetic or non-magnetic → magnetic field or not and certain metals attract or not [ability to be attracted by a magnet] Z Density → mass per unit volume of an object Z Chemical properties → melting & boiling points [how the material reacts with other substances. Will it burn? Will it rust? Will it react with water, or with an acid?] 2© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY MIXTURES MIXTURE: → combination of two or more pure substances, where these substances are not bound (or connected) together [each substance in the mixture still retains its own special properties BUT the composition can vary] HOMOGENEOUS MIXTURES MIXTURE [HOMOGENEOUS]: → composition is uniform (is the same throughout) and the different components of the mixture cannot be seen OTHER NAME = “solution” Z Solute > substance that dissolves in the solvent Z Solvent > largest amount E.G. : Z GAS SOLUTIONS [gases always mix COMPLETELY with each other] Z LIQUID SOLUTIONS [eg. coffee] Z SOLID SOLUTIONS [e.g. metal alloys] www.notedsummaries.co.za SEPARATION OF MIXTURES EXAMPLES [HOMOGENEOUS MIXTURES] PHASES Gas in gas Liquid in gas Gas in liquid Liquid in liquid Solid in liquid Liquid into solid COMPONENTS Oxygen in nitrogen Water vapor in air Solid in solid Copper and zinc EXAMPLE Carbon dioxide in water Alcohol in water Salt / sugar in water Mercury in silver Air Damp air Soda water Wine Pickle Mercury amalgam Brass HETEROGENEOUS MIXTURES MIXTURE [HETEROGENEOUS]: → the composition is not uniform (not the same throughout) and the different components of the mixture can be seen → combination of substances that cannot dissolve in each other MIXTURE Suspension Emulsion Gel Aerosol (mist) Smoke Foam Foam solid COMPONENTS Solid cement in water Oil in vinegar Liquid trapped in a solid Liquid in gas Solid in gas Gas trapped in liquid Gas trapped in solid EXAMPLE Cement slurry Salad dressing Fruit jelly Spray paint Smoke Shaving foam Foam rubber 3© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY → separate mixtures using physical methods > separate into pure components WITHOUT changing the properties of the substances PURE SUBSTANCES PURE SUBSTANCE / COMPONENT → substance that cannot be broken down into simpler components by physical methods / A single substance that is not mixed with anything else and all the particles are exactly the same [CONSISTS OF ONE TYPE OF SUBSTANCE: ELEMENT / COMPOUND] ELEMENTS → Pure substance that cannot be broken down into simpler substances by chemical methods [ONE KIND OF ATOM] COMPOUNDS → substance consisting of two or more different atoms and which are chemically bonded together into a single substance [chemical methods = separate into simpler substances] ELEMENTS COMPOUND MIXTURE ONE kind of atom Composition is CONSTANT Properties are UNIQUE Properties DIFFERENT from the properties of the constituent elements Components separated with CHEMICAL methods Composition = difference & consisting of 2 / more elements & compounds Properties = same as of constituent substances Components cannot be separated [physically / chemical] Components separated with PHYSICAL methods www.notedsummaries.co.za CRITERIA FOR PURITY 3 METHODS : 1. MEASURE MELTING POINT Temperature at which a solid turns into a liquid 2. MEASURE BOILING POINT Temperature at which a liquid changes to a gas 3. CHECK OF CHROMATOGRAM → process where substances are separated into their various components COMPOUNDS Atoms of elements = react with each other / other atoms of other elements to form BONDS COMPOUNDS: pure substances composed of 2 OR MORE types of elements in fixed proportions EACH COMPOUND HAS ITS OWN FORMULA: Z Show types of elements in the compound Z Number of atoms of each element in the compound CARBON DIOXIDE Co 1 x Carbon atom 2 x Oxygen atoms PURE SUBSTANCE = 1 SPOT ON CHROMATOGRAM ELEMENTS ELEMENT = very basic substance that materials are made of WATER ATOM= smallest particle that retains the chemical properties of an element HO 2 x hydrogen atoms 1 x oxygen atom ALL ATOMS OF AN ELEMENT ARE THE SAME KIND ATOMS OF A SPECIFIC ELEMENT CANNOT BE BROKEN DOWN INTO SIMPLE ATOMS BY CHEMICAL METHODS Names of elements = set of symbols with one or 2 letters 4© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY AMMONIA NH 1 x nitrogen atom 3 x hydrogen atoms www.notedsummaries.co.za NAMES + FORMULAS [SUBSTANCES] READ / ANALYZE COMPOUNDS: IONIC COMPOUNDS = ANIONS + CATIONS CATIONS: [mostly metal atoms] Hydrogen H Beryllium Be Aluminum Al Lithium Li Magnesium Mg Cr Sodium Na K Calcium Ca Ba chromium (III) Iron (III) Ag Hg Tin (II) Cu chromium (II) Manganese (II) Iron (II) Potassium IMPORTANT ELEMENT NAMES & SYMBOLS: Silver Mercury (I) Copper (I) Ammonia NH Barium Cr Mr Fe Co Sn Pb Lead (II) Cobalt (II) nickel(II) Copper (II) Zinc (II) Cobalt (III) chromium (VI) Manganese (VII) Cr Mn Fe Co Ni Cu Zn ANION: MONATOMY [1 element] = “-id” POLYATHONOMIC= more than one atom [net positive charge / net negative charge] 5© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za CHEMICAL FORMULAS & NAMES ANIONS: Fluoride Chloride Bromide Iodide Hydroxide Nitrite Nitrate Hydrogen carbonate Hydrogen sulphite Hydrogen sulfate F Cl Br I OH NO NO HCO HSO HSO Dihydrogen phosphate H PO Hypochlorite ClO Chlorate ClO Permanganate MnO Acetate (ethanoate) CH COO Oxide Peroxide Carbonate Sulfide Sulphite Sulfate Thiosulfate Chromate Dichromate Manganate Oxalate Hydrogen phosphate Nitride Phosphate Phosphide O O CO S SO SO S O CrO Cr O MnO C O HPO N PO P IMPORTANT: “ide” = 1 “ite” = 3/2 “ate” = 4/3 6© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY ACIDS Hydrogen chloride [hydrochloric acid] Hydrogen nitrate [nitric acid] Dihydrogen sulfate [sulfuric acid] Dihydrogen sulphite[sulfuric acid] Dihydrogen carbonate[carbonic acid] OXIDES Calcium oxide[slaked lime] Potassium oxide Copper(II) oxide Mercury(II) oxide Lithium oxide Lead(IV) oxide Magnesium oxide Iron oxide [magnetite] Sodium oxide Phosphorus pentoxide carbon dioxide [carbon dioxide gas] Sulfur dioxide hydrogen oxide [water] Carbon monoxide trioxygen [ozone] Nitrogen dioxide HCl HNO H SO H SO H CO CaO K O CuO HgO Li O PbO MgO Fe O Na O P O CO SO H O CO O NO www.notedsummaries.co.za HYDROXIDES Calcium hydroxide Ca(OH) Potassium hydroxide KOH Magnesium hydroxide Mg(OH) Sodium hydroxide NaOH CARBONATES Potassium carbonate K CO Barium carbonate BaCO Calcium carbonate CaCO Magnesium carbonate MgCO Sodium carbonate Na CO 10H 0 Sodium hydrogen carbonate NaHCO NITRATES Calcium nitrate Ca(NO ) Potassium nitrate KNO Silver nitrate AgNO Sodium nitrate NaNO SULPHATE Magnesium sulfate MgSO Barium sulfate BaSO Copper (II) sulfate CuSO 5H O Calcium sulfate CaSO 2H 0 Potassium sulfate K SO Sodium sulfate Na SO Zinc sulfate ZnSO Iron (II) sulfate FeSO 7© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY Barium chloride Sodium chloride Potassium chloride Copper(II) chloride Copper (I) chloride Silver chloride Calcium chloride Iron(II) chloride Iron(III) chloride Potassium bromide Lead(II) bromide Sodium bromide Silver bromide Potassium iodide Lead(II) iodide Sodium iodide Silver iodide CHLORIDES BaCl NaCl KCL CuCl CuCl AgCl CaCl FeCl FeCl BROMIDES KBr PbBr NaBr AgBr IODIDES KI PbI NaI AgI www.notedsummaries.co.za Methane Ethane Eating Etienne Propane Propene Butane Octane Methanol Ethanol Methanoic acid Ethanoic acid Glucose Sucrose ORGANIC COMPOUNDS CH C H C H C H C H C H C H C H CH O C H O CH O C H O C H O C H O WRITE CHEMICAL FORMULAS SODIUM OXIDE: Z Charge on sodium ion = +1 Z Charge on oxygen ion = -2 Na O ALUMINUM SULFATE: Z Charge on aluminum ion = +3 Z Charge on sulfate ion = -2 Al SO SCM of 2 and 3 = 6 [requires a positive charge of -6 and total negative charge of -6] 2 x Al ions needed for a total positive charge > 2 x (+3) = +6 3 x SO ions needed for a total negative charge > +3 x (-2) = -6 OVERALL LOAD ON COMPOUND = 0 FORMULA = Al (SO ) Let's see HOW? 1. 2. 3. 4. 5. Write down the SYMBOLS of all the BONDING IONS [symbol of the metal > positive ion = LEFT SIDE OF THE FORMULA] Determine charges of the bond ions & polyatomic ions Write down the charges of the different ions ABOVE THE SYMBOLS Work out how many IONS of each ELEMENT are needed so that the total charge of the FIRST ELEMENT's ions is equal to the TOTAL CHARGE of the SECOND ELEMENT's ions REMEMBER : TOTAL NEGATIVE CHARGE = TOTAL POSITIVE CHARGE 2 x sodium ions are needed to BALANCE the -2 charge of oxygen atom [neutral compound] FORMULA = Na O 8© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za METALS, METALLOIDS & NON-METALS METALS Z Z Z Z Z Z Z Z Z Solids (EXCLUDING MERCURY) High melting points Shiny + easily polished Crushable Stretchable GOOD CONDUCTORS OF ELECTRICITY COOL CONDUCTORS OF HEAT Strong + carries heavy weights Gray (GOLD + COPPER ONLY) NON-METALS Z Solids / gases at room temperature (EXCLUDING BROMINE) Z Molecular nonmetals = low melting & boiling points [diamond + SiO = hard + high melting points] Z Low densities Z Poor conductors of electricity = ISOLATORS Z Poor thermal conductors (ONLY DIAMOND + GRAPHITE > carbon atoms) Z Brittle + dull surface > solid Z Different colours METALLOIDS (semi-metals) 7 metalloids: bore (B); silicon (Si); germanium (Ge); arsenic (As); antimony (Sb); tellurium (Te); polonoim (Po) ELECTRICAL CONDUCTORS, SEMICONDUCTORS & CONDUCTORS INSULATORS → materials that conduct electricity easily ISOLATORS → materials that allow NO current to flow through them SEMICONDUCTORS metalloids = semiconductors (heated =  conductivity) Z Metals = good conductors of electric current Z Non-metals = bad conductors of electricity > ISOLATORS TEST ELECTRICAL CONDUCTIVITY: → use SERIES CIRCUIT > bulb burns = material IS A CONDUCTOR > bulb does not burn = insulator THERMAL CONDUCTORS & INSULATORS THERMAL CONDUCTOR: → Material that easily transmits energy in the form of heat HEAT / HEAT > energy moving from a hotter to a colder object [LIQUID = POOR CONDUCTOR; AIR / GAS = INSULATOR] Silicon & Germanium = semiconductors (heat =  conductivity) 9© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za MAGNETIC & NON-MAGNETIC MATERIALS MAGNETS CONSIST OF FERROMAGNETIC SUBSTANCES: Cobalt (Co) Nickel (Ni) Iron (Fe) Magnetite (Fe O ) Hermatite (Fe O ) MAGNETIC ALLOY: → Ferromagnetic material mixed with non-magnetic material [eg. Alnico = alloy with magnetic properties] → Ferromagnetic material / elements + ceramics + polymers = permanent magnets 10© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za STATES OF MATTER & KINETIC MOLECULAR THEORY 3 STATES OF MATTER CONDITION OF FABRIC DEPENDS ON: Z KINETIC ENERGY OF ITS PARTICLES [MOTION ENERGY] Brownian motion [Robert Brown]: = determines how much they can move around [determined by SPEED] → random, jerky motion of particles suspended in a medium. This movement pattern existstypically from random fluctuations in a particle's position Z INTERMOLECULAR FORCES BETWEEN PARTICLES within a fluid subdomain, followed by a shift to another subdomain. SOLID LIQUID GAS Z packed tight > a decent way Z do not move around > vibrate against each other Z strong force that holds them together Z Have very small spaces between them → matter RETAINS a fixed volume + shape Z loosely arranged > close together Z weak power Z small spaces Z move fining and sliding past each other → matter RETAINS a fixed volume [takes form of container] Z move a lot vining Z no order and far apart Z weak power Z large spaces → matter SITS OUT + occupies available volume = holds particles in the solid & liquid phase TOGETHER [kinetic energy  = intermolecular forces = change from one phase to another] TEMPERATURE TEMPERATURE OF A SUBSTANCE : → measure of its particles' AVERAGE KINETIC ENERGY  temperature =  faster movement of particles PHASE CHANGE → When a substance changes from one physical state (solid, liquid, gas) to another [reversibly] MELTING POINT: temperature at which transition occurs BOILING POINT: conversion due to heating FREEZING POINT: conversion ag.v. cooling down 11© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za PHASE CHANGE CONDENSATION: → process by which a gas or vapor changes into a liquid, either by cooling or by an increase in pressure EVAPORATION: → Changing from a liquid to a gas without boiling it SUBLIMATION: → Process where solid changes directly into a gas [eg. solid carbon dioxide > dry ice & iodine] PHASE CHANGE : WATER MELTING + BOILING POINTS SUBSTANCE Helium Chlorine Bromine Iodine Oxygen Nitrogen carbon [diamond] Phosphorus Sulphur Water Carbon dioxide Methane Ethanol Sugar Ammonia Copper Mercury Sodium Magnesium Lead Iron Silicon Germanium Table salt (NaCl) Rust (Fe O ) 12© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY NON-METALLIC ELEMENTS MELTING POINT -272 °C -101 °C -7 °C 114 °C -219 °C -210 °C 3550 °C 44 °C 115 °C NON-METALLIC COMPOUNDS 0 °C -79 °C -182 °C -114 °C 170 °C -78 °C METALS 1083 °C -39 °C 98 °C 650 °C 327 °C 1,536 °C METALLOIDS 1420 °C 940 °C SALTS 801 °C 1,565 °C BOILING POINT -269 °C -34 °C 58 °C 183 °C - 183 °C -196 °C 4,830 °C 277 °C 444 °C www.notedsummaries.co.za 100°C -57 °C -161 °C 78 °C DISBAND -33 °C 2,600 °C 357 °C 892 °C 1,107 °C 1,750 °C 3000 °C 3280 °C 2830 °C 1413 °C DISBAND KINETIC MOLECULAR THEORY Kinetic Molecular Theory: HEATING CURVE: → shows changes in temperature of the substance during a period of time while heating is taking place → Model that is a way to explain macroscopic observations at a molecular level → motion of particles in 3 states SOLID LIQUID GAS Z tightly packed > regular arrangement Z not moving around > vibrating against each other [around rest position] Z strong force keeps them together Z Have very small spaces between them [density ] Z NOT EASILY COMPRESSIBLE  temperature = absorbed energy + stronger vibration and average kinetic energy  = melt and move around freely Z loosely arranged > close together Z weak power Z small spaces [density  ] Z move fining and sliding past each other Z NOT EASILY COMPRESSIBLE Z Apply pressure in all directions on sides of container Heating = moving faster = liquid expands > evaporates and if boiling point is reached = gas phase Z move quickly Z no order and far apart Z weak to NO power Z large spaces [far apart > density  ] Z COMPRESSIBLE Z Exerts pressure due to collision of particles 13© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za THE ATOM ATOM: → basic BUILDING BLOCKS of matter > different atoms = elements ATOMIC MODEL Ernst Rutherford > The Nucleus: → Atom = empty spaces BUT a strong concentration of POSITIVE CHARGE in the center [NUCLEUS] → Positive particles = protons → Negatively charged particles = electrons John Dalton > Law of Multiple Niels Bohr > energy levels: Proportions: → Electrons move in orbits = energy levels → Electrons in each energy level = specific amount of energy → Elements = small particles (Atoms) → Atoms of given element = IDENTICAL & different from another Erwin Schrondinger > electron clouds: element → Atoms of 1 element = bond with atoms of other elements = chemical bonds → Atoms cannot be CREATED, DIVIDED / DESTROYED into smaller particles [CHEMICAL PROCESS] JJ Thomson > “plum pudding”: → Measure charge-to-mass volume ACCURATELY → Atom = negatively charged electrons stuck in the positively charged → Electrons move in electron clouds > quantum theory = wave mechanics ATOMS HAVE 3 MAIN PARTICLES: Protons (p ) neutrons (n ) electrons (e ) NUCLEUS (middle) > [NEUCLONS] = protons + neutrons PROTONS & NEUTRONS MASS = 1,67 × 10−27 kg ELECTRON MASS = 9,11 × 10−31 kg Protons = POSITIVE CHARGE; Electrons = NEGATIVE CHARGE BUT : NUMBER OF ELECTRONS = NUMBER OF PROTONS 14© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za ATOMS / NUCLEI OF ELEMENT: RELATIVE ATOMIC MASS RELATIVE ATOMIC MASS (A ): → an atom of an element is a number indicating how many times the mass of the atom is greater than one twelfth the mass of an atom of carbon-12. The mass of the carbon-12 atom is chosen as 12 atomic mass units (ame). HE ATOM: RELATIVE MASS 1 1 INSIGNIFICANT 𝐴 𝑍𝐸 𝑚𝑎𝑠𝑠 𝑛𝑢𝑚𝑏𝑒𝑟 𝑎𝑡𝑜𝑚 𝑛𝑢𝑚𝑏𝑒𝑟 𝐸 FOR EXAMPLE: STRUCTURE OF THE ATOM PARTICLE proton (p ) Neutron (n ) electron(e ) Nuclides > atom with a specific atomic number, atomic mass + energy state RELATIVE LOAD +1 0 -1 Atomic number (Z) → The number of protons in the nucleus of an atom of an element [position in Periodic Table] Mass number A → The total number of protons plus neutrons (number of nucleons) in the nucleus of the atom COMPOSITION OF ATOM: NUMBER OF PROTONS = Z NUMBER OF NEUTRONS = A – Z NUMBER OF ELECTRONS [NEUTRAL ATOM] = Z 15© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY H He Li ISOTYPE ISOTYPE: → Atoms of the same element with the same atomic number (number of protons) but with different mass numbers (protons and neutrons) REMEMBER RELATIVE ATOMIC MASS? Here's how we calculate it: 𝐴𝑟 = (% 𝑖𝑠𝑜𝑡𝑦𝑝𝑒 𝑎 × 𝑚𝑎𝑠𝑠 𝑖𝑠𝑜𝑡𝑦𝑝𝑒 𝑎) + (% 𝑖𝑠𝑜𝑡𝑦𝑝𝑒 𝑏 × 𝑚𝑎𝑠𝑠 𝑖𝑠𝑜𝑡𝑖𝑝𝑒 𝑏) 100 FOR EXAMPLE: Chlorine has 2 common isotypes: chlorine-35 (75.5%) & chlorine-37 (24.5%) 𝐴𝑟 = (75,5 × 35) + (24,5 × 37) = 35,5 100 www.notedsummaries.co.za LOWEST ENERGY LEVEL : GROUND STATE ISOTOPES PERCENTAGES: ELEMENT Neon (Ne) Copper (Cu) RELATIVE ATOMIC MASS 20,18 63.55 Boron (B) 10.81 Bromine (Br) 79.90 Most stable ISOTYPE Ne 90,92% Ne 0,26% Ne 8,82% Cu 69,20% Cu 30,80% B 20,00% B 80,00% Br 50,69% Br 49,31% ELECTRON CONFIGURATION [energy levels] ELECTRON CONFIGURATION [ENERGY LEVELS]: → Electrons arranged in fixed areas around the nucleus [WAY ELECTRONS ARE ARRANGED AROUND THE NUCLEUS] [electron absorbs energy > moves to higher energy level] EXCITED STATE [Valence Electrons] Unstable & falls back to ground state 4 TYPES OF ORBITALS s Spherical shape p d hourglass shape ENERGY LEVEL 1 = 1 x s orbital ENERGY LEVEL 2 = 1 x s-orbital + 3 x p-orbital [at right angles to each other] ENERGY LEVEL 3 + = contains d & f orbitals P-ORBITAL INTERFACE DIAGRAMS: ATOMIC ORBITALS ORBITALS: → most likely space of motion where an electron can be found in an atom REMEMBER BOHR'S PRINCIPLE: S-ORBITAL INTERFACE DIAGRAMS: Electrons in each energy level = specific amount of energy 16© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY f www.notedsummaries.co.za RULES : HOW THE ORBITAL DIAGRAM IS FILLED [atom with more than 1 electron] Aufbau principle: in the ground state of an atom or ion, electrons fill sub orbitals of the lowest available energy, then they fill suborbital of higher energy ELECTRON CONFIGURATION NOTATION Z Use circles / blocks > representation of ORBITALS Z Use arrows () for electrons > opposite spin Z Electrons = MAKE LOWEST ENERGY LEVEL FULL FIRST → closest to core [Aufbau] Z Pauli's Exclusion Principle → orbital can be occupied by MAXIMUM of 2 paired electrons [spin > opposite directions] Z ORDER OF FILLING OF ENERGY LEVELS [20 elements] = 1s, 2s, 2p, 3s, 4s, 3d, 4p Z Hund's rule: [p-orbitals, d-orbitals & f-orbitals] a single electron orders each orbital before the electron pair Z MAXIMUM NUMBER OF ELECTRONS = 2n² (n=energy level) ORBITAL BLOCK DIAGRAM ELECTRON CONFIGURATION [FIRST 20 ELEMENTS]: TYPES OF ORBITALS + ELECTRONS FOR EACH ENERGY LEVEL [FIRST 20 ELEMENTS]: ENERGY LEVEL ORBITALS PRESENTATION NUMBER OF ELECTRONS 4 4s ( 3 x 4p; 5x 4d; 7x4f) 4s 2 (+30) 3 3s 3p 3p 3p (5 x 3d) 3p 2 + 6 = 8 (+10) 3s 2 2s 2p 2p 2p 2p 2+6=8 2s 1 1s 1s 2 17© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 1s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2s 2p 2p 2p 2p 2p 2p 2p 2p 2p 2p 2p 2p 2p 2p 2p 2p 3s 3s 3s 3s 3s 3s 3s 3s 3s 3s 3p 3p 3p 3p 3p 3p 3p 4s 3p 4s 1s 1s = [He] [He] 2s [He] 2s [He] 2s 2p [He] 2s 2p [He] 2s 2p [He] 2s 2p [He] 2s 2p [He] 2s 2p = [Ne] [Ne] 3s [Ne] 3s [Ne] 3s 3p [Ne] 3s 3p [Ne] 3s 3p [Ne] 3s 3p [Ne] 3s 3p [Ne] 3s 3p = [Ar] [Ar] 4s [Ar] 4s www.notedsummaries.co.za THE PERIODIC TABLE Z H (hydrogen) – is a metal and non-metal and is found on both sides of the periodic table Z the elements are arranged in order of increasing atomic numbers, with the lightest element (H,HYDROGEN) in the upper left corner Z position of element tells whether it is a metal or non-metal (A) metals are found on the left side (B) non metals are found on the far right (C) tables have rows and columns Z there are 92 natural elements Z rows from left to right are called PERIODS (there are 7 periods) Z columns from top to bottom are called GROUPS (there are 18 groups) GROUP 1 : ALKALI METALS ALKALI METALS: → Stored in oil or paraffin to prevent contact with oxygen and water. Chemical reactivity increases from top to bottom in a group [ionization energy  > decrease the valence electron] lithium, sodium, potassium, rubidium, cesium, francium CHARACTERISTICS: Low density (floats on water) Soft > potassium = softest & lithium = hardest Silver coloured & shiny surface GOOD CONDUCTORS [heat + electricity] Fire in air = solid oxides [alkaline solutions] Reacts violently with water > hydrogen gas + alkaline solution of the metal hydroxide Z Form CATIONS > +1 charge Z Z Z Z Z Z GROUP 2 : ALKALI - EARTH METALS ALKALI EARTH METALS: → Chemical reactivity increases from top to bottom in a group beryllium, magnesium, calcium, strontium, barium + radium CHARACTERISTICS: Z Z Z Z Z 18© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY Silver coloured GOOD CONDUCTORS [heat + electricity] Fire in air = solid oxides [alkaline solutions] Reactivity with water DIFFERS Form CATIONS > +2 charge www.notedsummaries.co.za GROUP 17 : HALOGENS HALOGEN: → Diatomic elements. Consists of molecules with two atoms each. Chemical reactivity decreases from top to bottom in group fluorine, chlorine, bromine, iodine, astat [radioactive] ELECTRON CONFIGURATION VALENCE ELECTRONS: → elements in the same group have the same number of electrons in their outermost level [Is the electron that occurs in the highest (outermost) energy level] F Cl Br I F & Cl = yellow-green (room temperature) [TOXIC] Br = reddish brown liquid [TOXIC] I = purple crystals CHARACTERISTICS: Z Z Z Z Z Z Non-metals Diatomic molecules ANIONS > -1 charge Low melting points & boiling points > increase as you move down the group Coloured > colour becomes stronger > move down the group Reactivity  > move down the group GROUP 18 : NOBLE GASES NOBLE GASES: → Chemically unreactive. Monatomic gases with completed outer energy levels. helium, neon, argon, krypton, xenon, radon CHARACTERISTICS: Z Z Z Z UNREACTIVE Reactivity  > move down the group Boiling points  > move down the group 19© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY Z Number of VALENCE ELECTRONS = determines CHEMICAL PROPERTIES [involved in chemical bonding] Z NOBLE GASES = stability > UNREACTIVE > outermost energy levels = filled Z INCOMPLETE ENERGY LEVELS [Mg, Al, N, Cl] = UNSTABLE [change electron configuration > add / reduce electrons] VALENCIA = number of electrons that an atom must gain, give up / share to achieve the stability of a noble gas www.notedsummaries.co.za VALENCES [MAIN GROUPS]: Group number Valence electrons Valencia 1 2 13 14 15 16 17 18 1 2 3 4 5 6 7 8 1 2 3 4 3 2 1 0 PERIODICITY: → Repeating pattern of chemical and physical properties FORMULAS : HALIDES MX [M = metal ion ; X = GROUP 17 ELEMENT] For example : HCl, NaBr & LiF Halogens + Group 1 Elements IMPORTANT TERMS [PATTERNS IN THE PERIODIC TABLE]: → density, melting + boiling points & atomic radius = are indicated on the TILE OF THE ELEMENT! ATOMIC RADIUS [picometer]: → The distance between the nucleus and the outermost stable electron orbital [1/2 of distance between 2 nuclei / nuclei of 2 atoms in a diatomic molecule] Halogens + Group 2 Elements MX Halogens + Group 13 Elements MX For example : AlCl BF FORMULAS : OXIDES Oxygen + Group 1 elements M 0 Oxygen + Group 2 elements Mo Oxygen + Group 13 elements M O Oxygen + Group 14 elements Oxygen + Group 15 elements Oxygen + Group 16 elements Oxygen + Group 17 elements 20© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY For example: BeF CaCl MgI For example: Na O Li O For example: CaO MgO For example : Al O B O CO, CO , SiO React with Nitrogen: N O, NO, NO React with phosphorus: PO ,PO Sulfur + Oxygen : SO , SO Oxygen + Chlorine : Cl O , Cl O www.notedsummaries.co.za IONIZATION - ENERGY IONIZATION - ENERGY: → The energy absorbed/required by an atom/ion in the gas phase is given off as an electron → AMOUNT OF ENERGY required to remove an electron from a neutral atom [measure of how FIRMLY the electron is held in the atom]  ionization energy > harder to remove electron FIRST IONIZATION ENERGY → Energy required to remove a first electron from a neutral atom in the gas phase ELECTRON AFFINITY ELECTRON AFFINITY: → The energy that is given off/released when an electron is absorbed → ENERGY CHANGE that occurs when an electron is absorbed by an atom in the GAS STATE > forms ANION [INCREASE FROM LEFT TO RIGHT OVER A PERIOD ()] Halogens = highest () electron affinity values X(g) + e → X (g) + electron affinity SECOND / THIRD IONIZATION ENERGY → Energy required to remove electron from positive ion with a charge of =1 in the gas phase → Energies required to remove each additional electron & ARE USUALLY GREATER M + first ionization energy → M + e M + second ionization energy → M + e M + third ionization energy → M + e GROUP 1 ELEMENTS FORM POSITIVE IONS Na : [Ne] 3s + ionization energy→ Na : [Ne] + e 21© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY ELECTRON NEGATIVITY ELECTRON NEGATIVITY: → The ability of an atom to attract electrons in a bond (BONDING ELECTRON PAIR) to itself → RELATIVE CONCEPT : can only measure an element's electronegativity in relation to the electronegativity of OTHER ELEMENTS [INCREASE FROM LEFT TO RIGHT OVER A PERIOD () & DECREASE WITH INCREASING ATOMIC NUMBER IN A GROUP ()] www.notedsummaries.co.za CHEMICAL BONDS → 1. 2. 3. WHAT IS A CHEMICAL BOND? Force that holds atoms together to form a single unit 3 POSSIBLE COMBINATIONS: Metal + metal → METAL BONDING Nonmetal + nonmetal → COVALENT BOND Metal + nonmetal → IONIC BONDING LEWIS DIAGRAMS → diagrams showing the bonding between atoms of a molecule, as well as the lone pairs of electrons that can exist in the molecule → Chemical symbol for element is used to represent an atom of the element and its core electrons. The valence electrons are represented by dots in specific positions around the symbol REMEMBER! : elements in the SAME GROUP = SIMILAR OUTER ELECTRON CONFIGURATIONS / LEWIS DOCK SYMBOLS 22© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY COVALENT BOND COVALENT BONDS: → Sharing of electrons between non-metal atoms to form a molecule [The electron in the highest energy level is shared between the two non-metals] → formed when two half-filled orbitals of two atoms overlap. The atoms then share two electron pairs to each obtain a noble gas structure. In a double bond, 4 electrons (2 pairs of electrons) are shared to form two bonds. An example where double covalent bonds occur is between two oxygen atoms to form an oxygen molecule COVALENT BONDS [SINGLE]: → formed when each atom must share one electron to obtain a noble gas structure. In a single bond, two electrons (1 pair of electrons) are shared to form a bond COVALENT BONDS [TRIPLE]: → formed when three half-filled orbitals of two atoms overlap. The atoms then share three electron pairs to each obtain a noble gas structure. In a triple bond, 6 electrons (3 pairs of electrons) are shared to form three bonds. An example where a triple covalent bond occurs is between two nitrogen atoms to form a nitrogen molecule www.notedsummaries.co.za IONIC BONDING SINGLE-COVALENT BONDS: H + CL → H CL H + H + O → H O IONIC BONDS: → Transfer of electrons from a metal atom to a nonmetal atom H 3H + N → H N H H [The electron in the highest energy level is transferred to chlorine, thus creating a positive ion and a negative ion] [combustion of magnesium in oxygen] > electrically NEUTRAL > resultant magnesium ion (Mg ) & oxide ion (O ) = neon electron configuration DOUBLE BOND: O + O → O O Mg + O → Mg [ O ] [reaction between calcium metal & chlorine atoms > 2x Cl atoms receive one electron each from the potassium atom] TRIPLE BOND / TRIPLE BOND: Cl + Ca + Cl → Ca 2[ Cl ] / CaCl N + N → N N IONIC BONDS: 23© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY 1 / more electrons transferred from metal to nonmetal Metal = POSITIVE ion & nonmetal = NEGATIVE ion Ions = packed in crystal lattice > ELECTROSTATIC FORCES ELECTRONICALLY NEUTRAL www.notedsummaries.co.za METAL BOND METAL BINDINGS: → the electrostatic attraction between the positive atomic residues and the sea of delocalized (freely moving) valence electrons that surround them RELATIVE MOLECULAR & FORMULA MASS RELATIVE MOLECULAR MASS (Mr): → sum of all the relative atomic masses of atoms in the molecule For example: RELATIVE ATOMIC MASS of carbon = 12.0 & oxygen = 16.0 SO : Carbon dioxide (molecular mass) = CO = 12.0 + 16.0 + 16.0 = 44.0 [we add 16.0 > 2 times because there are 2 x oxygen atoms] RELATIVE FORMULA MASSA: → equal to the sum of the relative atomic masses of the atoms in the chemical formula [IONIC SUBSTANCES] For example: Law of Constant Composition: All samples of a given compound have the SAME ELEMENTAL COMPOSITION 24© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY Formula for KMnO : 39.0 + 54.9 + (4 x 16.0) = 157.9 [we multiply the 16.0 by 4 because there are 4x oxygen atoms] www.notedsummaries.co.za CHEMICAL BONDS PARTICLES OF SUBSTANCES ATOMS + COMPOUND Atoms = small & basic units of matter & substances [Group 18 > noble gases = single atoms > monatomic gases] MOLECULAR SUBSTANCES COVALENT > ONE ELEMENT: IONIC SUBSTANCES INORGANIC IONIC SUBSTANCES = substances formed from a reaction between a METAL and a NON-METAL = [SALTS] E.g. Table salt > Na + Cl ions > NaCl Potassium permanganate (KMnO ) permanganate ion (MnO ) PROPERTIES : IONIC COMPOUNDS Z Z Z Solids > high melting & boiling points [ions > strong electrostatic forces] Salty > hard + brittle CANNOT CONDUCT ELECTRIC CURRENT [no free electrons / charged particles] > ELECTROLYTES > can conduct → consists of METAL ATOMS < lattice structure packed with REGULARLY SPACED POSITIVE IONS [outer electron = DELOCALIZED pool of electrons surrounding the POSITIVE IONS] = METAL PRESENTATION OF COMPOUNDS Compounds = group of 2 or more atoms > held together by CHEMICAL BONDS [bonded in FIXED RATIO] & is ELECTRICALLY NEUTRAL ATOMS > BIND = COMPOUNDS METALLIC SUBSTANCES 3D MODELS BALL & STICK METHOD: → distinguish between single, double and triple bonds COVALENT > MORE THAN ONE ELEMENT: > diatomic molecules : 2 atoms of 2 elements bond : CO NH C H O & C H SPACE-FILLING MODELS: → show HOW BIG the atoms are in relation to each other & how they are arranged in space COVALENT NETWORK STRUCTURES: [3D structures > very strong] ALLOTROPES : forms of the same elements + difference in physical + chemical properties PROPERTIES : COVALENT BONDS Z Z Z Simple molecule = low melting & boiling points [weak intermolecular forces] Covalent network structures = high melting & boiling points [covalent bond is strong between atoms > inflexible + definite direction] ISOLATORS > no free electrons to impart electrical charge / thermal conduction [exception = granite & diamond > heat conductor] 25© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY DIAGRAMS FORMULAS MOLECULAR FORMULA = COVALENT MOLECULAR STRUCTURES [O H O C H ] EMPIRICAL FORMULAS = COVALENT NETWORK STRUCTURES [SiO > silicon dioxide] www.notedsummaries.co.za PHYSICAL + CHEMICAL CHANGE PHYSICAL CHANGE PHYSICAL CHANGE: → PARTICLES ARE ARRANGEMENT [rearrangement of molecule] → does not change the composition of the substance but the appearance or state (solid substance, liquid substance, gas) FEATURES: Z no new substances formed Z energy change small compared to chemical change Z intermolecular forces = MUCH WEAKER than the chemical bonds between atoms in covalent, ionic & metallic bonds Z mass, number of atoms and molecule are conserved FOR EXAMPLE: Phase change > melting, dissolving, vaporizing & other change of states SEPARATION TECHNIQUES = distillation, filtration & paper chromatography CHEMICAL CHANGE CHEMICAL CHANGE: → change involving the CONVERSION of one or more substances into one or more substances → when two or more substances react with each other to form a new compound with NEW CHEMICAL PROPERTIES DURING CHEMICAL CHANGE: Arrangement of particles changed. (The atoms or molecules or ions regroup). Particles can either be broken down or formed. During a reaction, the amount of molecules of a substance changes but the total amount of matter does not change 2 TYPES OF CHANGES: DECOMPOSITION REACTION: A single compound that changes to form two or more single substances. Z Change in the number of gas molecules occurs when the reactants form the products. Z The number of atoms and the mass do not change. SYNTHESIS REACTION: It is a reaction where the reactants combine with substances to form a new product eg: combustion of methane in oxygen CH + O → CO + H O 26© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za CHEMICAL CHANGE = WORD EQUATION & BALANCED SYMBOL EQUATION: WORD COMPARISON: Hydrogen + Oxygen → Water Reactants → Product BALANCED COMPARISON: 2 H + O → 2H O Law of Conservation of Mass: In a chemical reaction, the sum of the mass of the reactants is EQUAL to the sum of the mass of the products REMEMBER: molecules are NOT retained during a CHEMICAL REACTION SYNTHESIS OF AMMONIA IN HARBER PROCESS: WORD COMPARISON: Hydrogen gas + Nitrogen gas → Ammonia BALANCED EQUATION [DECOMPOSITION OF HYDROGEN PEROXIDE > water + oxygen gas]: 2 H O → 2H O + O VERY IMPORTANT: THE LAW OF CONSERVATION OF MASS IS RELATED TO THE LAW OF CONSTANT COMPOSITION Law of Constant Composition: All samples of a given CHEMICAL BOND have the same ELEMENTAL COMPOSITION 27© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY BALANCED COMPARISON: 3H + N → 2NH = 4 x molecule of reactants = 2 molecule of product [NUMBER OF MOLECULES ARE NOT RETAINED] BUT! The atoms are simply rearranged > STAY THE SAME HOW DO WE SHOW IT? = by calculating relative molecular masses of the reactants & products Sum of relative molecular mass left side = Sum of relative molecular mass right side M(N ) + M(3H ) = M(2NH ) 2 x 14.0 + 3 (2 x 1.0) = 2 (14.0 + (3 x 1.0)) 28.0 + 6, 0 = 34.0 THEREFORE! 28 g N + 6 g H → 34 g NH. www.notedsummaries.co.za REPRESENTATION OF CHEMICAL CHANGE HOW TO WRITE A BALANCED CHEMICAL EQUATION: 1. Write down the CORRECT formulas of the reactants and products 2. Work out how many atoms of each element appear on both sides of the arrow 3. Add reactants / products to the left and right of the arrow to balance the number of atoms of each element 4. NEVER CHANGE THE FORMULAS TO BALANCE AN EQUATION! [only add balancing numbers before a formula WHERE NECESSARY] 5. Add phase symbols where possible [ s = solid; l = liquid; g = gas; aq = aqueous solution] Na + H O → NaOH + H Na + 2H O → 2NaH + H [balance the hydrogen atoms by adding another H O on the LEFT and another NaOH on the RIGHT] 2Na + 2H O → 2NaOH + H [balance the Na atoms > add ONE MORE Na to the LEFT SIDE] 2Na(𝑠) + 2H O (𝑙)→ 2NaOH(𝑎𝑞) + H (𝑔) [phase symbols] H + N → NH H + N → 2NH [balance the N atoms by adding another NH on the RIGHT SIDE] 3H + N → 2NH [balance the H atoms by adding 3 before the H] 3H (𝑔) + N (𝑔) → 2NH (𝑔)[ [phase symbols] ENERGY TRANSFERRED THE STRONGER A BOND = THE MORE ENERGY IS INVOLVED ENERGY = FOLLOWS LAW OF CONSERVATION OF ENERGY EXOTHERMICAL REACTION Z Reactants and products are affected by the energy involved in a reaction. Z Energy absorbed is greater than the energy released when bonds form and break Z a reaction where energy is released to the environment. The products have more energy than the reactants [COOL DOWN] Z It is a spontaneous reaction. ENDOTHERMIC REACTION: Z The energy absorbed is greater than the energy released. Z Energy is therefore absorbed from the environment. Z a reaction where heat is absorbed from the environment [HOT!] E.G : 28© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY H O (𝑙) + energy → H O (𝑔) www.notedsummaries.co.za ENDOTHERMIC REACTION: → releases LESS energy on the RIGHT SIDE than the amount ABSORBED on the LEFT SIDE Reactants → Products Breaking strong bonds → Weak bonds form High energy INPUT → Low energy OUTPUT EXOTHERMICAL REACTION: → releases MORE energy on the RIGHT SIDE than the amount ABSORBED on the LEFT SIDE Reactants → Products Break weak bonds → Strong bonds form Low energy INPUT → High energy OUTPUT 29© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za CHEMICAL CHANGE : REACTIONS IN AQUEOUS SOLUTIONS IONS > AQUEOUS SOLUTION POLARITY OF WATER Water Z Z Z Z Z Most common solvent. Is a polar molecule because: W The molecule has an angular shape (caused by the unbonded electrons, which repel the electrons in the bonds and thus also the H atoms unevenly (a.)). W The atoms' difference in electronegativity (oxygen is more electronegative and attracts the electrons in the bonds more strongly (b.) and so the molecule becomes more negative (𝛿 −) on the oxygen side and more positive (𝛿+) on the hydrogen side). This unsymmetrical distribution of charges causes the molecule to form a dipole [> 2 POLES]. Dissolves ionic and polar molecular substances. Positive + negative charges = equal > CANCELL EACH OTHER > overall charge on water molecule = 0 30© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY SOLUTION PROCESS SOLUTION OF IONIC SUBSTANCES Z Positive and negative ions in ionic substances are held together by strong electrostatic forces. Z The forces are overcome by the attraction of polar water molecules. Z Dissociation takes place: W The bonds in the ionic crystals break, W and the ions diffuse into the solvent. W This is a physical process and not a chemical process. NaCl (𝑠) → Na (𝑎𝑞) + Cl (𝑎𝑞) [Sodium Chloride] CuSO (𝑠) → Cu (𝑎𝑞) + SO (𝑎𝑞) [Copper(II) sulfate] KOH (𝑠) → K (𝑎𝑞) + OH (𝑎𝑞) [Potassium hydroxide CA(NO ) (𝑠) → Ca (𝑎𝑞) + 2NO (𝑎𝑞) [Calcium nitrate] Z Hydration takes place: W The negative sides of the polar water molecule orient themselves towards the loose positive ions, W the positive sides of the polar water molecule orient themselves towards the loose negative ions. W Thus the ions (positive or negative) are surrounded by water. www.notedsummaries.co.za ELECTROLYTES + CONDUCTIVITY SOLUTION OF COVALENT SUBSTANCES [IONIZATION] Z The particles of some substances (sugar) break apart (without forming ions) and spread evenly through the solution [PHYSICAL PROCESS] Z Ionization takes place: W Acids and ammonia react chemically with water to form ions. W The polar covalent molecule and the polar water molecule's opposite poles attract each other. W The polar covalent molecule attracts the hydrogen of the water molecule so strongly, that the hydrogen breaks away and leaves behind a negative hydroxide ion (OH-). W The positive hydrogen bonds with the covalent molecule to form a positive ion (eg NH +). W The ions spread evenly throughout the solution Electrolyte W Acts as a conductor to allow electrical charges to flow from one point to another. W Does not possess free electrons. W Contains ions that act as charge carriers, ∴ electric current transferred from one point to another by the ions moving in the solution (known as electrolysis). HCl (𝑔) → H (𝑎𝑞) + Cl (𝑎𝑞) [Hydrochloric acid] HNO (𝑔) → H (𝑎𝑞) + NO (𝑎𝑞) [Nitric acid] H SO (𝑙) → 2H (𝑎𝑞) + SO (𝑎𝑞) [Sulphuric acid] Z Hydrolysis / HYDRATION takes place: W Involves the breakdown of water / solution in water > solid ionic crystals are broken down into ions CO (𝑔) + H O (𝑙) → H CO (𝑎𝑞) [Carbonic acid] SO (𝑔) + H O (𝑙) → H SO (𝑎𝑞) [Sulphuric acid] 2NO (𝑔) + H O (𝑙) → HNO (𝑎𝑞) + HNO (𝑎𝑞) [Nitric acid + nitric acid] H O (𝑙) + NaCl (𝑠) → Na (𝑎𝑞) + Cl (𝑎𝑞) [Sodium chloride crystal solution] 31© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY Soluble ionic and only some molecular compounds W Good conductive solution = strong electrolyte o Forms many ions, ∴ possess a high concentration of ions. Most molecular compounds W Poorly conductive solution = poor electrolyte o form few ions, ∴ possess a low concentration of ions W No conductivity = non-electrolyte o Forms no ions (only neutral molecule) www.notedsummaries.co.za CHEMICAL REACTIONS CONDUCTIVITY Depends on: Z Z Z Type of substance (polar or non-polar/ionic or covalent) Solubility of the substance (and therefore temperature) Concentration of ions (weak / strong electrolytes) SOLUBILITY RULES Z PRECIPITATION / PRECIPITATION REACTIONS Type of ion exchange reaction in the reaction of ionic solutions. Z Insoluble salt (solid) forms during the reaction and settles out in the solution (forms a precipitate). Z Opposite of dissolve. NaCl (𝑎𝑞) + AgNO (𝑎𝑞) → AgCl (𝑠) + NaNO (𝑎𝑞) SOLUBLE All Group I salts (Li+, Na+, K+) All ammonium salts (NH+) EXCEPTION - All nitrate salts (NO ) All salts of chlorides (Cl-) Halides All salts of bromides (Br-) All salts of iodides (I-) All sulfate salts (SO ) Ag+, Pb2+, Hg2+, Cu+ Ag+, Pb2+, Hg2+ UNSOLVABLE All carbonate salts (CO ) All sulphide salts (S2-) All phosphate salts (PO ) All hydroxide salts (OH-) All oxide salts (O2-) EXCEPTION Group I, NH+ and Ca2+ Group I, NH Group I, NH , Ba , Ca Group I, Ba2+ Z Use to: Z Identify ions in solutions. Z To remove unwanted ions in the solution. Z To manufacture certain chemicals. Z To do quantitative calculations. REMEMBER THE RULES OF SOLUBILITY! Ag+, Pb2+, Hg2+ Ag+, Pb2+, Ba2+, Ca2+ 32© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za TEST FOR SULPHATE: TESTING FOR IONS IN A SOLUTION TEST FOR HALIDES: CHLORIDE: → sodium chloride + silver nitrate = white precipitate BALANCED EQUATION NaCl (𝑎𝑞) + AgNO (𝑎𝑞) → AgCl (𝑠) + NaNO (𝑎𝑞) IONIC EQUATION: Na (𝑎𝑞) + Cl (𝑎𝑞) + Ag (𝑎𝑞) + NO (𝑎𝑞) → AgCl (𝑠) + Na (𝑎𝑞) + NO (𝑎𝑞) BROMIDE: → bromide solution + silver nitrate = cream coloured precipitate BALANCED EQUATION NaBr (𝑎𝑞) + AgNO (𝑎𝑞) → AgBr (s) + NaNO (𝑎𝑞) IODIDE: → iodide solution + silver nitrate = yellow precipitate BALANCED EQUATION NaI (𝑎𝑞) + AgNO (𝑎𝑞) → AgI (𝑠) + NaNO (𝑎𝑞) BUT! [UNSOLVABLE] AgCl precipitate > nitric acid [AgCl (𝑠) + HNO (𝑎𝑞) →] AgBr > nitric acid [AgBr (𝑠) + HNO (𝑎𝑞) →] Z Add Ba(NO ) to (Ba ions) o BaSO will precipitate. Z Then add a concentrated acid to the precipitate. o If no reaction occurs, it is sulfate. → BARIUM SULPHATE = white precipitate BALANCED EQUATION Ba(NO ) (𝑎𝑞) + Na SO (𝑎𝑞) → BaSO (𝑠) + 2NaNO (𝑎𝑞) IONIC EQUATION: Ba (aq) + 2NO (aq) + 2 Na (aq) + SO (aq) → BaSO (s) + 2Na (aq) + 2NO (aq) TEST FOR CARBONATES: Z Add Ba(NO ) to (Ba ions) o BaCO will precipitate. Z Then add a concentrated acid to the precipitate. o If a reaction occurs, and a gas is released, it is a carbonate. → BARIUM CARBONATE= white precipitate [INSOLUBLE] BALANCED EQUATION Na CO (𝑎𝑞) + Ba(NO ) (𝑎𝑞) → BaCO (𝑠) + 2NaNO (𝑎𝑞) NITRIC ACID + CARBONATE = DISAPPEAR PRECISION: BaCO (𝑠) + 2HNO (𝑎𝑞) → Ba(NO ) (𝑎𝑞) + CO (𝑔) + H O (𝑙) AgI > nitric acid [AgI (𝑠) + HNO (𝑎𝑞) →] 33© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za pH & INDICATORS: ION EXCHANGE REACTIONS POSITIVE IONS EXCHANGE DIFFERENT NEGATIVE IONS KIND OF RESPONSE Precipitation reaction Gas formation reactions Acid-Base reaction DRIVING POWER Formation of insoluble salt by the exchange of metal cations. Formation of a gas (usually a reaction with an acid). Exchange of protons (positive ions) and the formation of salt and water. ACID-BASE REACTIONS ACIDS Z Taste sour Z Causes colour changes in plant pigments Z Reacts with certain metals = hydrogen gas Z React with carbonates + hydrogen carbonates = carbon dioxide gas Z AQUEOUS ACID SOLUTIONS > CONDUCTED ELECTRICITY BASES Z Tastes bitter Z Feel smooth Z Causes colour change in plant pigments Z Aqueous BASE SOLUTIONS = ALKALINES > CONDUCTED ELECTRICITY pH value 0-6 (acidic) 7 (neutral) 8-14 (bases) pH value 0-6 (acidic) 7 (neutral) 8-14 (bases) pH value 0-6 (acidic) 7 (neutral) 8-14 (bases) pH value 0-6 (acidic) 7 (neutral) 8-14 (bases) pH value 0-6 (acidic) 7 (neutral) 8-14 (bases) 34© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY INDICATOR = Bromothymol blue Colour Yellow Green Blue INDICATOR = Phenolphthalein Colour Colourless Colourless Pink - red INDICATOR = Methyl orange Colour Red, orange, yellow Green Blue, violet, purple INDICATOR = Red litmus paper Colour Red Red Blue INDICATOR = Blue litmus paper Colour Red Blue Blue www.notedsummaries.co.za REACTIONS : ACIDS AND BASES Z Type of ion exchange reaction in the reaction of ionic solutions. Z Also known as a neutralization reaction. Z Involves the transfer of protons (H+) HNO + NaOH → NaNO + H O ∴ H (𝑎𝑞) + OH (𝑎𝑞) → H O (𝑙) Z Acids and bases are ranked on a scale of 0 to 14 to indicate acidity. Z The concentration of 𝑂𝐻- (base) and 𝐻+ (acidic) ions in a solution determine whether the solution is an acid or a base. Z ∴ has a neutral solution equally 𝑂𝐻- and 𝐻+ ions. Reactions W One of the products will be a salt [type of salt = depends on the acid used] Hydrogen chloride → chloride salt Hydrogen sulfate → sulfate salt Hydrogen nitrate → nitrate salt etc. Metal oxide (base) + acid → salt + water Metal hydroxide (base) + acid → salt + water METAL OXIDE (BASE) + ACID → SALT + WATER H SO (𝑎𝑞) + CuO (𝑠) → CuSO (𝑎𝑞) + H O (𝑙) METAL CARBONATE (BASE) + ACID → SALT + WATER + CARBON DIOXIDE H SO (Aq) + MgCO (s) → MgSO (aq) + H O (l) + CO (g) HCl (aq) + NaHCO (s) → NaCl (aq) + H O (l) + CO (g) METAL (BASE) + ACID → SALT + HYDROGEN 2HCl (𝑎𝑞) + Zn (𝑠) → ZnCl (𝑎𝑞) + H (𝑔) ACID-BASE NEUTRALIZATION ACID + BASE → SALT + WATER BALANCED EQUATION HCl (𝑎𝑞) + NaOH (𝑎𝑞) → NaCl (𝑎𝑞) + H O (𝑙) IONIC EQUATION H (𝑎𝑞) + Cl (𝑎𝑞) + Na (𝑎𝑞) + OH (𝑎𝑞) → Na (𝑎𝑞) + Cl (𝑎𝑞) + H O (𝑙) NET IONIC EQUATION H (𝑎𝑞) + OH (𝑎𝑞) → H O (𝑙) Metal carbonate (base) + acid → salt + water + carbon dioxide Metal (base) + acid → salt + hydrogen 35© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za REDOX REACTIONS (OXIDATIONREDUCTION) → Involves the transfer of electrons from one reactant to another. ∴ the charges of atoms and ions from a reactant differs from those same atoms or ions in the products. The charge (or probable charge) of an atom in a compound is called that atom's oxidation number and corresponds to the valence of the atom. Z A redox reaction can be identified by the change in the charge of the atoms/ions. Z Consists of an oxidation and reduction half-reaction, these reactions take place simultaneously. Z Substance that loses electrons → undergoes oxidation (and becomes positive) and is the reducing agent. Z Substance that takes up electrons → undergoes reduction (and becomes negative) and is the oxidizing agent. DISPLACEMENT OF HYDROGEN 2Na (s) + 2H O (l) → 2NaOH (aq) + H (g) Zn (s) + 2HCl (aq) → ZnCl (aq) + H (g) Mg (s) + 2HCl (aq) → MgCl (aq) + H (g) DISPLACEMENT OF METAL Metal in a metal salt replaced with a more reactive metal Zn(s) + Cu (aq) → Zn (aq) + Cu(s) [Zn metal atoms lose 2x electrons each (Zn ) & Cu ions 2x electrons to form Cu metal > SO = spectator ions] DISPLACEMENT OF HALOGEN Halogen in a salt replaced with a more reactive halogen H2 in 𝐻2𝑂 replace metal by the exchange of electrons. Z 𝑁𝑎 loses an electron (oxidizes) and becomes 𝑁𝑎+, ∴ was 0, is now +1. Z 𝐻+ of 𝐻2𝑂 takes up the electron (reduces) and becomes neutral, ∴ was +1, is now 0 36© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY Cl (g) + 2Br (aq) → 2Cl (aq) + Br (l) Cl (g) + 2I (aq) → 2Cl (aq) + I (s) Br (l) + 2I (aq) → 2Br (aq) + I (s) SODIUM + = SPECTATOR ION IN 1ST REACTION: Cl (g) + 2NaBr (aq) → 2NaCl (aq) + Br (l) www.notedsummaries.co.za CHEMICAL CHANGE : QUANTITATIVE ASPECTS WHAT IS STOIGHOMETRY? →branch of chemistry > relationships of atoms, molecule + formula units in a chemical reaction MOLECULAR & FORMULA MASS DEFINITION OF A MOLE (amount of substance) Amount of substance that contains the same amount of particles as there are atoms in 12 grams of Carbon-12. Avogardo's constant [602 204 500 000 000 000 000 000] works more with the above groups : N – 6.02 x 10. This number has certain important implications regarding atoms or formula units (Ions) or molecules: Z 1 mole of an element contains 6.02 x 10 atoms Z 1 mole of a covalent bond contains 6.02 x 10 molecules Z 1 mole of a formula unit contains 6.02 x10 formula units MASSES OF AN ELEMENT: How do we know how many atoms or molecules or formula units there are in a substance? Z 1 oxygen – O contains 1 atom of oxygen Z 1 water molecule – H O contains 3 atoms Z 1 compound HCl – contains 2mol of ions Atomic mass– mass of one atom ( ame ) – only with elements Molecular mass– mass of a molecule – only for covalent bonds ( g.mol ) Formula mass– mass of a formula unit (g.mol ) 37© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za EMPIRICAL FORMULA PERCENTAGE COMPOSITION Empirical Formula of a compound indicates the simplest form of a compound. Operations mostly take place in a 100 gram sample. EMPIRICAL FORMULA COMPOUND Water Butane Hydrogen peroxide Benzene H0 CH HO CH MOLECULAR FORMULA HO CH HO CH HOW TO CALCULATE THE EMPIRICAL FORMULA: 1. Consider 100g of the compound & CONVERT PERCENTAGES TO MASS 2. Determine the atomic mass of each element 3. Divide the percentage (grams) by the atomic mass of the element (COMPARISON ON PREVIOUS PAGE) = number of MOLE OF EACH ELEMENT (work to 2 decimal places) 4. Divide the mole quantity by the SMALLEST MOLE VALUE in the calculated set to get whole numbers 5. Write down the empirical formula → indicates the amount percentage of the substance present REMEMBER! LAW OF CONSTANT COMPOSITION IS INVOLVED HERE! THE SUM OF THE PERCENTAGES MUST BE 100% HOW TO CALCULATE THE PERCENTAGE COMPOUND: 1. Determine the ATOMIC MASS of each element + work out the molar mass of the compound 2. Divide (EACH ELEMENT) the atomic mass by the molar mass + multiply by 100 > DETERMINE PERCENTAGE 3. DIVIDE (COMPOUNDS) the molecular / formula mass by the molar mass + multiply by 100 EXAMPLE [CALCULATION FROM EMPIRICAL FORMULA]: Element E.g. Hg E.g. Cl Mass (grams) E.g. 73.9 given as % E.g. 26.1 given as % mole ( mole ) Work out moles Work out moles from 0.37 from 0.74 Relationship 0.37/0.37 = 1 0.74/0.37 = 2 The Empirical Formula of HgCl10 Physical Sciences] CHEMISTRY 38© Noted Summaries [Grade www.notedsummaries.co.za CONCENTRATION OF SOLUTIONS CONCENTRATION: → AMOUNT OF SOLUTE present in a given solvent MOLAR VOLUMES OF GASES standard temperature and pressure ( STD ) > formula: [𝑚𝑜𝑙 ∙ 𝑑𝑚−3 ] MOLARITY (M) / molar concentration: → number of moles of a DISSOLVED SUBSTANCE in a solution of 1 liter (1 dm ) STANDARD SOLUTION: → solution with a KNOWN CONCENTRATION THAT WAS ACCURATELY MADE UP 1 atmosphere pressure ( 101.3 kPa ) Room temperature 27°C 39© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY www.notedsummaries.co.za CHEMICAL SYSTEMS : HYDROSPHERE EARTH'S SURFACE : 71%WATER: Z 97% = OCEANS Z 76% = FRESHWATER [glaciers frozen / polar ice caps / ice ground] Z Groundwater (residual) = lakes & rivers Z Only 0.01% available for human consumption [recycled by WATER CYCLE] THE WATER CYCLE → PHYSICAL CHANGES [phase changes] > water moves from the hydrosphere to the atmosphere and lithosphere and back to the hydrosphere HYDROSPHERE → GLOBAL SYSTEMS WATER CYCLE = connects the atmosphere, hydrosphere & lithosphere → hydrosphere > presence of water DETERMINES climate & geology + influences all life > water = lays foundation for the natural CHEMISTRY ON EARTH [life = availability of good quality water] ATMOSPHERE LITHOSPHERE BIOSPHERE 40© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY Z Movement of water (evaporation > hydrosphere + atmosphere) = driving force for WEATHER PATTERNS Z Clouds = small water droplets Z EROSION= landscape > water penetrates rocks > flows over land and down to the sea Z WATER= AGENT THAT BREAKS ROCKS [WEATHERING] PHYSICAL WEATHERING: → wind, water & temperature [melting & freezing = cracks > rocks break apart] CHEMICAL WEATHERING: → carbon dioxide in rainwater = acid rain > oxides (sulphur and nitrogen) = limestone Z Living organisms [plants + animals] > need water for survival www.notedsummaries.co.za WATER CONTENT WATER RESOURCES > SA RIVERS DAMS GROUND WATER Z +- 75% of water in the sea Z Orange River (Gariep River) > flows from east to west [longest in the country] Z Sources = Drakensberg & Malotiberge Z Flow INTO THE ATLANTIC OCEAN Z Very important for drinking water & irrigation AND TO GENERATE HYDROELECTRICITY & recreational facilities Z Hot + dry climate = evaporation due to large pond surfaces Z Presence = disrupts balance of rivers EFFECT ON ECOLOGY: → barrier to movement of fish & reduces fish population due to less egg laying → disrupt wetlands, forests & riverine habitats > no adaptation & diversity of animals  → sediment bag EFFECT ON HUMANS: → breeding grounds for mosquitoes (malaria) + snails (bilharzia) → lost fertile farmland & communities are separated Z Rainwater that is stored in old, hard rock formations (aquifers). Z Sand + gravel (river banks) Z Use windmills to bring groundwater to the surface > on boiled in ponds Z Groundwater (coastal areas) > extracted from the ground without treatment & proper research = salt from seawater can end up in it Z Aquifers = become salty & unusable for humans, animals and plants 41© Noted Summaries [Grade 10 Physical Sciences] CHEMISTRY WATER IN RIVERS AND DAMs = NEVER CLEAN Z May contain bacteria + dissolved substances (salts + gases). Z Contaminants

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