Basic Chemistry Lecture Notes PDF

COURSE OUTLINE CHAPTER 1 – BASIC TOOLS OF CHEMISTRY a. Measurements of matter b. Laboratory measurements c. Matter and energy d. Significant figures and conversion of units e. Laboratory measurements f. Matter and energy What is chemistry The science of matter and the transformations it can under...

COURSE OUTLINE CHAPTER 1 – BASIC TOOLS OF CHEMISTRY a. Measurements of matter b. Laboratory measurements c. Matter and energy d. Significant figures and conversion of units e. Laboratory measurements f. Matter and energy What is chemistry The science of matter and the transformations it can undergo. Why should you study it? It helps us understand our surroundings and the way we function. It plays a central role in medicine, engineering and many sciences. SI UNITS Quantity Unit Symbol Length Meters m Mass Kilogram Kg Time seconds s Electric Current Ampere A Temperature Kelvin K Amount of mole mol Substance Luminous candela Cd Intensity DERIVE UNITS Quantity Unit Symbol Volume Cubic meter or Liter M^3 or L Density Kilogram per Cubic Kg/m^3 Speed or Velocity Meter per second m/s Concentration Moles per cubic meter Mol/m^3 Force Newton N (Kg m/s^2) Energy Joule J (Kg m^2/s^2) Power Watt W (J/s^2) Quantity of electricity Coulomb Coul (A*s) Electrical Potential Volt V ( W/A) DECIMAL MULTIPLIER Practice example : 1.0cm = 1.0 x ___m 3.2pg = 3.2 x ____g 5.0uL = 5.0 x ____L 8.5mg = 8.5 x ____g 6.1 MW =  Scientific Notation To Add or Subtract Scientifi c Notation, N1 and N2 must be expressed with the same exponent. Then add/subtract N1 and N2;the exponents will not change. Example: 1.90 x 10 3 1.90 x 10 3 + 0.30 x 10 3 - 0.30 x 10 3 2.20 x 10 3 1.60 x 10 3 02/17/2025 8  Scientific Notation To Multiply Scientifi c Notation, N1 and N2 must multiply in usual way. Add the exponents together. Example: (4.0 x 10 6) x (2.0 x 10 3) = (4.0 x 2.0) x 10 6+3 = 8.0 x 10 9 02/17/2025 9  Scientific Notation To Divide Scientifi c Notation, N1 and N2 must divide in usual way. Subtract the exponents together. Example: (4.0 x 10 = 6 ) 4.0 2.0 x 103 x106-3 = (2.0 x 10 3) 2.0 02/17/2025 10  Scientific Notation ACTIVITY Solve and express in correct scientifi c notation. a.(8.0 x 10 9) x (3.0 x 10 -3) b.(8.0 x 10 9) / (4.0 x 10 -3) c.(8.1 x 10 9) + (3.0 x 10 8 ) d.(8.1 x 10 9) - (3.0 x 10 8) e. (3.0 x 10 -3) / (6.0 x 10 9 )  Rules of Significant figures 1. Non-zero digits are always significant. 103.230002 2. All final zeros after the decimal point are significant. 0.0420 3. Zeros between two other significant digits are always significant. 2004 6.01 4. Zeros used only for spacing the decimal point are not significant. 100 0.00000233  Rules of Significant figures 4. If a number is greater than 1, all zeros written after the decimal point is significant. Ex. 9.0 mg has 2 SF, 70.050 mL has 5 SF 5. If a number is less than 1, then only the zeros at the end of the number and the zeros that are between nonzero digits are significant. Ex. 0.090kg has 2 SF, 0.6006 L SIGNIFICANT FIGURES PRACTICE Example 1 Give the Example 2: number of significant Add the following units figures for each of the of the length and following. express the answer in 0.0723g = meters: 31cm , 23.43m = 632mm,0.2001km and 700kg = 180dm 0.0080020 g = Rules for rounding off Significant figures 5 or grater, the Example next higher 4.3627g is 4.363g to 4 number is used significant figure for the last 2.350g is 2.4 to 2 significant significant figure figures Example Less than 5, 8.6123g to 8.6 for 2 retain the value significant figures 5.146g to 5 for 1 significant figure Rules for rounding off Significant figures in mathematical equation For addition and subtraction For multiplication or division Round to the FEWEST Round the answer to the PLACES past decimal. LEAST # OF SIG FIGS in the problems Measurement and Dimensional Precision Analysis Reproducibility of a measurement. Can be determined by standard deviation Accuracy How close to the real value. Laboratory measurements measures distance Len gth between objects measures the Wei ght amount of matter in and mas an object s TEMPERATURE What is temperature ? Is the measurement of how hot or cold an object is Is determined by the Average Kinetic energy of the particles of the object Take note: higher the temp = molecules move faster Lower the temp = molecules move slower Thermometer – device to measure temperature Kelvin (K) Celsius (C) Fahrenheit (F) Equation K=C+ C = (F – 32) F = C * 9/5 + 273 *5/9 32 Convert the following OC= 5/9 ( OF – 32) O F= (9/5 OC) + 32 K= OC + 273 Convert the ff. a. 810 OF to OC b. 19 OC to K c. 300 OC to OF d. 500 OF to K e. 70K to C Formula for volume Example problem: 1. Calculate the volume of cm^3 of block of wood which is 5.2cm on each side? 2. what is the volume in cm3 of an iron rod 2.4cm in diameter and 1m ? ACTIVITY 1. Calculate the volume of block of wood which has the ff. dimension : 5.8 cm, 3.18 cm , 0.1 m 2. What is the volume in cm3 of the cylindrical rod which has a diameter of 5.18 cm and a length of 0.5 m ? DENSITY Mass per unit volume of a substance Usually expressed as grams per cubic centimeter Specific gravity The ratio of the weight of the substance to the weight of an equal volume of a substance chosen as a standard Example problem Calculate the density and the specific gravity of a body that has a mass of 320g and a volume of 40cm^3 at 25C Answer the following 1. When a 23.5g piece of gold was placed into a graduated cylinder containing 50.0ml of water. Find the density of the gold? 2. how many grams of mercury ( density 14.7g/ml) will occupy of 30.5mL  What is matter Is anything that has both mass and volume Matter has energy Everything is around you Special Property of matter Propert y Malleabili is the property of a material to deform or change ty shape when subjected to compressive forces without cracking or breaking Ductility the ability of a material to be drawn or stretched into thin wires without breaking. brittlenes one that is easily fractured or cracked when s subjected to tension or compression forces. Hardness that measures a material's resistance to deformation, scratching, or abrasion. In other words, it refers to how difficult it is to scratch or dent a surface of a material. Elasticity is the ability of a material to return to its original Physical vs chemical properties of matter Physical Chemical properties properties Colour, odour, taste , texture , shape Stability Density Combustion Specific gravity Oxidation stress Boiling point Reactivity Freezing point Melting point Possible chemical bonding Solubility and viscosity Ionization Physical properties can be measured without changing the composition of a substance. Temperature Pressure Mass Volume State (solid, liquid, or gas) Melting point Boiling point Density Color Shape of crystals Ice melting PHYSICAL CHANGE The same substance is present before and after a physical change. physical state may change. e.g. ice melting (solid water → liquid water). gross shape may change. e.g. a lump of lead hammered into a sheet. size may change. e.g. a piece of wood is cut in two. Chemical property A chemical reaction that a substance can undergo. Chemical Reaction? Reactant atoms rearrange into different substances. Sucrose caramelizes, then turns to carbon on heating. sucrose heat carbon + water reactant products  Describe the change as chemical or physical: (a) A cup of household bleach changes the color of your favorite T-shirt from purple to pink. Chemical change (b) Fuels in the space shuttle (hydrogen and oxygen) combine to give water and provide energy to lift the shuttle into space. Chemical change (c) An ice cube in your glass of lemonade melts. Physical change https://sciencenotes.org/wp-content/uploads/ 2020/09/Intensive-and-Extensive-Properties.png CLASSIFICATION OF MATTER: ACCORDING TO SHAPE Classification of matter: ACCORDING TO SHAPE PROPERTY SOLID LIQUID GAS SHAPE DEFINITE NOT DEFINITE UNLESS NOT DEFINITE UNLESS TAKES SHAPE OF TAKES SHAPE OF CONTAINER CONTAINER VOLUME DEFINITE DEFINITE NO DEFINITE – CAN BE EXPAND OR COMPRESS STRUCTUR PARTICLES ARE PARTICLES ARE PARTICLES ARE FAR E VERY CLOSE TO NEITHER TOO CLOSE APART EACH OTHER NOR TOO FAR FROM EACH OTHER NO OF ANY, DEPENDS ONE NONE SURFACE OF THE SHAPE PICTURE  Classification of matter: ACCORDING TO SHAPE Bose- Einstein condensate Plasma - Exist at extremely low temperature - exist in high temperature - Behave as though they were a single - State of matter in which atoms have particle been striped of their electrons  Classification of matter: according to origin or source ACCORDING TO ORIGIN ORGANIC INORGANIC MATTER MATTER LIVING NON-LIVING THINGS THINGS Example: Example: sugar , dna , iron , gold , proteins metal Classification of matter: ACCORDING TO COMPOSITION  DEFINITION OF TERMS ELEMENT It is the simplest form of matter; Example – contains only one kind of atom hydrogen, Cannot be decomposed by ordinary nitrogen , means phosphorus , iron , mercury COMPOUND Contains two or more elements or more Example – water , kinds of atoms combined chemically in Salt , zinc sulphide definite propotion by mass , alcohol , Constituent elements can be separated methane , sugar by chemical means MIXTURE Composed of two or more substances, either element or compounds combined Components retain their properties and can be separated by physical means HOMOGENO Consist of only one phase Example – US MIXTURE Uniform in properties and composition seawater, air , soil Some component is not visible HETREGENO Has two or more phases or region Example : blood, Classifying Matter Mixtures of substances are either: Homogeneous two or more substances in the same phase. completely uniform. Heterogeneous properties in one region differ from the properties in another region. a microscope may be needed to see the variation. Substances & Mixtures Sample heterogeneous homogeneous blood air apple oil & vinegar dressing milk filtered ocean water Blood appears homogeneous to the unaided eye, but not under a microscope. “Homogenized” milk appears homogeneous, but not under a microscope. Energy – ability to do work Law of conversion of energy Energy can't be created nor destroy by transferred to one from to another form Law of Conservation of Mass states that in a closed system, the total mass of the system remains constant, and it is not created or destroyed during a chemical reaction. This means that the total mass of reactants in a chemical reaction is equal to the total mass of the products. Law of Definite Composition: The law of definite composition states that a pure compound always contains the same elements in the same proportion by mass. Law of Multiple Proportions: The law of multiple proportions states that when two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in ratios of small whole numbers.