Science Review Notes PDF

Chemistry: Big Ideas- Chemical vs Physical Change A chemical property is something that can only be measured by changing one chemical into another. e.g.) A match is flammable Iron can rust ---> corrosiveness A physical property is something that can be determined without changing into a ne...

Chemistry: Big Ideas- Chemical vs Physical Change A chemical property is something that can only be measured by changing one chemical into another. e.g.) A match is flammable Iron can rust ---> corrosiveness A physical property is something that can be determined without changing into a new substance. e.g.) Glass is brittle (can shatter) The water is 12 C Physical Properties  State of matterWhether a substance is solid, liquid or gas  OdourSmell (sweet, sour, etc.)  TextureHow the surface feels (rough, smooth)  LustreHow well an object reflects light- is it shiny or dull?  MalleabilityHow easily a substance can be hammered flat without shattering. All metals are malleable  DuctilityHow easily a substance can be pulled into a wire. Do Not mistake with malleability!!  BrittlenessHow easily a substance shatters  ViscosityHow a substance resists flowing. Honey is very viscous. Water is not.  HardnessA substance's resistance to being scratched. Glass is hard. Diamond is very hard.  DensityDensity is the ratio of mass and volume D=m/V Whether an object floats or sinks in water. The density of water is 1.0 kg/L or 1.0 g/mL or 1.0 g/cm3 If the density is less than 1, it will float in water If the density is greater than 1, it will sink in water  SolubilityHow well a substance dissolves in water.  ConductivityHow easily electricity or heat pass through a substance. Metals are highly conductive. Chemical Properties: Chemical properties can only be tested by changing a substance into a new chemical. List of Chemical Properties: Reactivity: How easily a substance reacts with … e.g.) Reactivity with acids Reactivity with oxygen Stability: The substance’s ability to resist reactions Corrosivity: The ability to slowly react with oxygen (rust) Flammability: The ability to quickly react with oxygen Combustibility: The ability to explode when reacting with oxygen. Signs of a chemical change (5): 1) Permanent change in colour 2) Spontaneous change in temperature 3) Smoke/bubbles/new gas created 4) Light produced (without electricity or external heat source) 5) A new solid is created when two liquids are mixed (precipitate). Bohr-Rutherford Diagrams Process: #protons = atomic number # neutrons = mass# - atomic # List these in the nucleus. Electrons are arranged based on the periodic table. Patterns/Trends on the Periodic Table a) Atomic radius: - As you move down a group, the radius gets larger because there are more energy levels. - As you move to the right in a period, the atoms get smaller. This happens because there are more protons pulling the electrons towards the nucleus. The atom with the largest radius is Francium The atom with the smallest radius is Helium. b) Reactivity - Metals: A very reactive metal will lose electrons easily. This means the largest metals will be the most reactive. - Non-Metals: A very reactive non-metal gains electrons easily. This means the smallest non-metals are most reactive - Noble gases: These non-metals don’t react because their valence shell (outer orbit) is full. Practice on paper!!  e.g.) Magnesium Lithium Potassium Sodium Smaller details- Families on the periodic table The periodic Table is organized by grouping elements with similar properties and then arranging them by mass. Important groups: Metals: All metals are malleable, lustrous, and conduct heat/electricity Metalloids: have some properties of metals but not all three. Alkali metals: (Li, Na, K, Rb, Cs, Fr) These are the very reactive metals and will react in water Alkaline earth metals: (Be, Mg, Ca, Sr, Ba, Ra) These metals are somewhat reactive. They may have a small reaction in water but all react with acid. Halogens: (F, Cl, Br, I, At) These non-metals are very reactive. Often they are used as disinfectants. *Hydrogen is often considered its own group. In some cases, it acts like an alkali metal and in others it acts as halogen. Noble gases: (He, Ne, Ar, Kr, Xe, Rn) These non-metals do not react. They are already stable. (Xenon can be forced to react in certain circumstances) Naming compounds A binary ionic compound will always have a metal and a non-metal reacting. The metal is always listed first.  Molecular Compounds: occur when 2 non-metals share electrons. The general system of naming compounds is to have the full name of the first element but the second element has the ending changed to ide. NaCl: Sodium Chloride. MgF2: Magnesium fluoride. (In ionic compounds, the numbers don't change the name) Molecular compounds can have different results using the same 2 elements, so we needs to specify which one we are using. The way we do this is we use a prefix to say how many atoms there are of each.  1mono  2di  3tri  4tetra  5penta  6hexa  7hepta  8octa CO2: Carbon dioxide (can/could be monocarbon dioxide) P1S3: Diphosphorus Trisulfide PN: Phosphorus mononitride (When it is a molecular compound and there are no numbers, put mono in front of the second element either way) Space: Big Ideas- Gravity Gravity creates an apparent force of attraction between any two objects with mass. Objects with more mass have a stronger gravitational pull. Objects closer together have a stronger attraction. Gravity acts everywhere.  ^replace r with d, the distance the masses are apart. Solar System The Solar System is defined as all of the objects gravitationally bound to the Sun (held near the sun by gravity). The Sun: This is a star. It produces massive amounts of heat and light through nuclear fusion. Planets: (8) 1) A planet orbits the sun 2) Large enough that gravity has made them spherical 3) They have cleared their orbit of other objects like asteroids Dwarf Planets (like Pluto) 1) A planet orbits the sun 2) Large enough that gravity has made them spherical Planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. (My Very Excellent Mother Just Served Us Noodles) Dwarf Planets: Pluto, Ceres, Eris and more. Moons are spherical objects that orbit a planet. Moons are not a requirement for planets. Mercury and Venus have no moons. Jupiter has 95, Saturn has 146. Dwarf planets can also have moons. Planets with rings are sort of like an asteroid belt around the planet. Astronomical Units (AU): This is the average distance from the Earth to the Sun. It is used as a scale to measure inside our solar system. Red Shift-Blue Shift We know stars give off certain frequencies of light as seen through a spectroscope but the light we observe is slightly longer wavelengths (redder) than it should be. This happens because of the Doppler Effect. When a source of waves is moving away from us, the waves get longer (Red Shifted). When the source of waves is moving towards us, the waves get shorter (Blue Shifted). All stars we see are Red Shifted meaning the Universe is still expanding. Stars further away from us are more red shifted meaning they are moving away from us faster. This suggests that the speed of expansion is increasing. HR diagrams Stars in the top left part of the HR diagram are heavier, larger, more luminous and have a higher surface temperature. In contrast, stars in the bottom right part of the HR diagram are lighter, smaller, less luminous and have a lower surface temperature. Our Sun is a main-sequence star. Smaller details- Dark Matter vs Dark Energy Our current understanding of gravity is based on the work of Einstein. Our measurements of stars in other galaxies seems to be too fast to be explained by our theories. The only way the theory could work is if there was a significant amount of matter we can not detect. This is referred to as Dark Matter. Gravity should be slowing the expansion of the Universe but our measurements say the expansion is speeding up. For this to happen, there must be some kind of unknown energy being added. This is called Dark Energy. Dark matter is the possibility of a matter that we cannot detect, and is affecting our understandings and theories of the measurement of stars. Dark Energy is the possibility of an unknown energy speeding up the expansion of the Universe. The Big Bang Around 13.5 Billion years ago, the universe had a rapid expansion (NOT an explosion, an expansion) from a very small point. The early universe was extremely hot and could be described as being entirely of energy before particles started forming. Evidence of the Big Bang: 1) The universe is expanding so it must have been smaller in the past 2) When looking at the farthest parts of the observable universe, we see the chemicals that match what the early universe should have (hydrogen, helium) 3) The furthest away/oldest stars match our expectations for a rapid expansion 4) Cosmic Microwave Background Radiation: - If the early universe was extremely dense, it would be giving off light at extremely high energy levels because it was so hot. As the universe expanded, these gamma rays stretched out/cooled so that they have become microwaves and we see these microwaves evenly in all directions (when accounting for the movement of the Earth) Asteroids, Meteorites, Meteors, Meteoroid Asteroids: Small rocky objects that orbit the sun. They have irregular shapes and can be from meters to kilometers across. Most asteroids are found in a belt between Mars and Jupiter or the Kuiper Belt where Pluto is but some are in irregular orbits. Meteoroids are small asteroids near the Earth's orbit. A meteor is a meteoroid that enters the Earth’s atmosphere (shooting star). The heat from moving through the atmosphere makes it briefly light up. A meteorite is a meteor that has survived to hit the ground. Comets are chunks mostly of frozen gas that have very long orbits around the sun. When they get closer to the sun, they get heated and form a tail. The tail always points away from the sun. Comets originate in the Oort Cloud, a region at the far extremes of the Solar System. Eclipses  Solar Lunar  Sun ---> Moon ---> EarthSun ---> Earth ---> Moon  Can only be seen in a small part of EarthCan be seen by anyone on the night side of Earth  Happens during a new moonHappens during a full moon The Moon’s period of rotation is roughly 28 days but since it orbits on a slight angle, it is not in position for an eclipse every month. There are several lunar eclipses each year. Solar eclipses happen fairly regularly as well but since they can only be seen on a small section of the Earth, they are effectively very rare. The moon also causes tides. The gravitational pull from the moon causes water to be pulled slightly towards the moon causing a high tide on that part of the oceans. The opposite side of the Earth also has a high tide because of symmetry resulting in 2 areas of high tides and 2 areas of low tides meaning each tide lasts approximately 6 hours. Electricity: Big Ideas- Law of Electric Charges Same charges repel, while opposite charges attract Activity Series A neutral object has an equal number of positive and negative charges. A positively charged object has more positives. A negatively charged object has more negatives. The electrostatic series is a way of comparing two materials to determine which will become positive and which will become negative when rubbed together. The one closer to the positive end will become positive and the one closer to the negative end will become negative.  e.g.) When rubbing amber and silk, silk will become + and amber will become - Applications of Static Electricity 1) Lightning - The discharge/grounding of large static buildup. A lightning rod allows a path for the electricity to flow, avoiding sensitive parts of the building. 2) Electronic Manufacturing - The movement of people in clothes builds up a static charge. To prevent damage to electronics, the workers will be constantly grounded. 3) Photocopiers - They use static electricity to attract the ink to the proper parts of the paper. 4) Air filtration - Static charges in the filter attract particles so they can not pass through. *Ohm's Law Charge: Unit Coulombs, C Essentially the amount of excess electrons or protons. 1 electron or proton has a charge of 1.6 x 10-19 C Voltage: Unit Volts, V Voltage is the amount of energy a charge would get or use. 1 V = 1 Joule/Coulomb Voltage is provided by the battery or power supply Current (I) Unit Amperes (Amps), A Current is the amount of charge that passes a point per second (the speed). 1 A = 1 Coulomb/second Current is a result of the voltage and the resistance Resistance (R) Unit Ohms, (the Greek letter omega) Resistance is a measure of how difficult it is for electricity to flow through a material (related to insulators and conductors) Relationships: More voltage means higher current More resistance means lower current Voltage = current x resistance or V=IR This is called Ohm’s Law. ^Practice in notebook!!! Smaller details- Charging by Friction vs Contact Friction: Rubbing two objects together can cause one object to lose electrons and the other to gain them. The object that loses electrons becomes positively charged, and the object that gains electrons becomes negatively charged. Contact: A charged object is touched to a neutral object Insulators vs conductors A conductor is a material that allows electrons to flow freely through it, making it useful for carrying electric current. An insulator is a material that resists the flow of electrons, so it does not allow electric current to pass through it. A conductor allows current to flow easily through it. Insulators don't allow current to flow through it. Electric charges are absent in insulator. Series vs parallel In a series circuit, the components are connected in a line and the same current flows through all of them. In a parallel circuit, the components are connected so that each component has its own separate branch and the same voltage is applied to each component. *Power and Cost We pay for electrical energy. In metric, the standard unit of energy is Joules but when using electricity, it makes sense to use a different unit. Power: The rate (or how quickly) energy is used. P=Energy/time Unit: Watts, W or Joules/second A LED bulb may use 5 W. A microwave may use 1100 W Energy = Power x time A 5W light bulb used for 8 hours E = 5W x 28 800s = 144 000J (60s/min x 60 min/h x 8 h = 28 800s) For Electric generation, we use a different unit for energy Kilowatt-hours 5 W = 51000 = 0.005 kW E = 0.005kW x 8h = 0.04 kWh A 1100 W microwave used for 10 minutes would be 11001000kW10 minutes60 minutes=0.183 kWh Cost of Electricity Cost = rate x Energy Right now, electricity costs 12.2 cents per kWh. Calculate how much money the light bulb and microwave cost. Light Bulb Microwave 0.04 kWh x 12.2¢ 0.183kWh x 12.2¢ = 0.5¢ = 2.2¢ Biology: Big Ideas- *Trophic Levels Apple tree → Fly → Sparrow → Hawk Producer ---------Consumers ------------- Primary Secondary Tertiary These terms describe how that species gets its energy Trophic levels are a description of where on a food chain a species is. Apple tree → Fly → Sparrow → Hawk 1st 2nd 3rd 4th Autotroph -------heterotroph -------- All species access energy so they can use it to: - Grow - Move - Heal - Reproduce This means that most of the energy a species takes in is used up in its life and very little energy is able to be passed on to its predators. On average, only 10% of the energy an organism takes in can be passed on to the next trophic level. The metric unit of energy is Joules (J). Calories is a non metric unit for energy. Apple tree → Fly → Sparrow → Hawk 50 000J 5 000J 500J 50J This means that species at a higher trophic level will typically have to eat many of its prey (a hawk will need to eat many sparrows in its life). Because each step has so much less energy available, it does not make sense for long food chains to exist.  Energy in Ecosystem Energy is transferred between organisms in food webs from producers to consumers. The energy is used by organisms to carry out complex tasks. The vast majority of energy that exists in food webs originates from the sun and is converted (transformed) into chemical energy by the process of photosynthesis in plants. Photosynthesis: This is a chemical reaction where sunlight is turned into sugars. sunlight Carbon dioxide + Water ----------> oxygen + sugar 6CO2 + 6H2O → 6O2 + C6H12O6 Cellular Respiration: the chemical reaction where sugars are turned into energy Sugar + Oxygen → Water + Carbon Dioxide (+ energy) Plants use photosynthesis. All species use cellular respiration. Food Chains/Webs Food Chain: A food chain shows how energy is passed through an ecosystem as species eat other species. e.g.) corn → chicken → human Create 4 food chains that would typically occur in nature. A food chain is rarely longer than 5 species because it becomes less energy efficient. Food Web: A food web is like a food chain but recognizes that most species have multiple sources of food and/or are eaten by multiple species. These help us understand the effect that the population of one species can have on other species in that ecosystem. Population Growth Curves  I - Lag Phase: the population grows slowly because there are few individuals able to reproduce II - Exponential Growth Phase: Once the population gets large enough, it expands rapidly III - Plateau Phase: As the population nears the carrying capacity, growth slows down and levels out. This graph assumes the carrying capacity remains constant. Smaller details- Biotic vs Abiotic Biotic factors - Factors that affect the ecosystem that are or once were living. For example, wood is biotic since it is a direct product of a living tree. Abiotic factors - Factors that affect an ecosystem that are not from living matter. E.g.) wind, rain, rocks. Ecological Pyramids Pyramids are often used to depict certain characteristics in an ecosystem. 1) Pyramid of Numbers: these show the number of individuals at each level of a food chain.  When we have small species such as flies, this pyramid may be inverted. Pyramid of biomass: These show the total mass of all the individuals in a species in a particular ecosystem These can be pyramid-like or they can be inverted.  3) Pyramid of Energy: these show the amount of energy passed on to each higher level. These will always be wider on the base and narrowest at the top. On average, only 10% of the energy from each level gets passed along in a useful form. Predator vs Prey A predator is an organism that eats another organism. The prey is the organism which the predator eats. Symbiotic Symbiosis is defined as a close, prolonged association between two or more different biological species  Mutualisma relationship in which both species are mutually benefited.   Commensalisma relationship in which one organism benefits but the other is neither helped nor harmed.  Parasitisma relationship between the two living species in which one organism is benefitted at the expense of the other