CH 101 1st Edition Lecture 1 Outline of Current LectureI. Basic Chemistry DefinitionsA. Converting from Grams to Moles and Grams to MoleculesII. Balancing Chemical EquationsIII. Finding the Molar Mass of a MoleculeIV. Introduction to StoichiometryA. Converting from Grams to MolesCurrent LectureAppendix A:I. Basic Chemistry DefinitionsAtom - The smallest component of an element. An atom is not the smallest form of matter but it is the smallest form of matter that still has elemental properties. Oxygen is an atom but O2 is not an atom. In a molecule like HNO2 there is 1 Hydrogen atom, 1 Nitrogen atom and 2 Oxygen atoms. Element – A group of the same type of atoms. H (Hydrogen) and Ne (Neon) are elements and can be found onthe periodic table. There are certain elements that are diatomic and are only considered an element when bonded in pairs, N2, O2, F2, Cl2, Br2, I2, and At2. Molecule – Two or more atoms stuck together. A molecule can be composed of the same element or of different elements, O2 and H2O are both molecules.Compound – Two or more different atoms stuck together. A compound is always a molecule but a molecule is not always a compound. H2O and CO2 are both compounds but O2 is not.Avogadro’s number (the mole) – Avogadro’s number is used to determine the amount of atoms or molecules in a certain amount of grams or moles of a substance. Similar to the word “dozen”, the word “mole” is a representation of an amount. In the way that a dozen = 12, a mole = 6.022x1023. A mole of any substance equals 6.022x1023 atoms. In 1 mole of HNO2 molecules there is 1 mole of Hydrogen, 1 mole of Nitrogen and 2 moles of Oxygen.A. Converting from Grams to Moles and Grams to MoleculesEx) How many Na atoms are in 65.0 grams of Na?65.0 grams of Na  Start with what you know65.0 g Na = 1 mole Na / 22.99 g Na  Multiply by the ratio of moles to grams of Na so that the grams cancel. 1 mole Na has 22.99 g (this is the atomic mass of Na), and 1 mole of any element has 6.022x1023 atomsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.65.0 g Na = 1 mole Na / 22.99 g Na = 6.022x1023 atoms of Na / 1 mole Na  Now multiply by the ratio of atoms to moles, and 1 mole of any element has 6.022x1023 atoms65.0 g Na = 6.002x1023 atoms Na / 22.99 g Na = 1.703x1024 atoms Na  When you are finding atoms expect to get a large number as the answer. Also this equation can be simplified into 65.0g Na = 6.002x1023 atoms Na / 22.99 g Na = 1.703x1024 The same equation is used to convert from grams to molecules except you use the molar mass of the moleculeinstead of the atomic mass.Ex) Find the number of molecules in a 2.56 gram sample of SO22.56 g SO2 = 1 mole SO2 / 64.063 g SO2  Multiply by the ratio of moles to grams of SO2, grams of SO2 is found by calculating the molar mass (32.065) + 2(15.99) = 64.0632.56 g SO2 = 1 mole SO2 / 64.063 g SO2 = 6.022x1023 molecules SO2 / 1 mole SO2 = 2.41x1022 molecules SO2II. Balancing Chemical Equations- Balancing equations are important because you have to know the amount of each substance needed to produce the desired product. The easiest way to balance an equation is to…1) Start with the most complicated molecule or the molecule that contains the most elements2) Try to find a coefficient that will allow the amount of atoms in the reactants equal to the amount of atoms in the product3) Leave the diatomic molecules (such as O2) or elements (such as H) for last because the coefficients of these won’t affect anything else in the equation.Ex) Balance the equation: O2 + Al  Al2O3 In this equation there are two oxygen atoms and one aluminum atom on the reactant side and on the product side there are two Aluminum atoms and three oxygen atoms. Start plugging in coefficients to try and balance the equation. __O2 + _2_Al = __Al2O3  Now there are two Aluminum atoms on each side but the Oxygen atoms aren’t balanced, try a different coefficient and this time start with the Al2O3._2_O2 + _4_Al = _2_Al2O3  This is a balanced equationIII. Finding the Molar Mass of a Molecule – The molar mass is the mass of a certain element or substance. The molar mass of an element is found on the periodic table, under the element’s symbol. Oxygen’s molar mass is 15.999 as found on the periodic table. - To calculate the molar mass of a compound, you simply add the molar mass of the elements that make up the compound after multiplying them by their subscripts.Ex) Find the molar mass of Al2(SO4)3Molar mass of Al = 26.982, First, find the molar mass of each elementMolar mass of S = 32.065Molar mass of O = 15.9992(26.982) + 3(32.065) + 12(15.999) Plug in the molar mass of each element and multiply each molar mass by the subscript, notice that SO4 is multiplied by three so 3(S) and 3(O4). = 342.147  Answer, the molar mass of Al2(SO4)3IV. Introduction to Stoichiometry – Using ratios between quantities to determine the amount of a substance after a reaction or the forming of a compound.- These ratios are used to determine the amount of a substance when it undergoes some kind of change, like in a chemical reaction. Ex) 1 dollar = 100 pennies, the ratio is 1 meaning that they are equal amounts. So how many pennies are in .56 dollars? Since the ratio is 1 there would be 56 pennies to every .56 dollars.What happens when the ratio is not 1:1, the process becomes more challenging. In this case, you would have to take the given amount of substance 1 and multiply it by the ratio of substance 2 to substance 1 so that the units of substance 1 cancel each other and you find the correct amount of substance 2.Ex) 1 dollar = 20 Nickels, the ratio is 1 because if someone has 1 dollar they have just as much as someone else who has 20 nickels. So how many nickels are in .55 dollars? Take the amount of dollars given to you (.55) and set it equal to the ratio of nickels to dollars so that the dollars cancel each other.X amount of substance 1 = ratio of substance 2 / ratio of substance 1 = Y amount of substance 2 .55 dollars = 20 nickels / 1 dollar = ? nickels Set up your equation .55 dollars = 20 nickels / 1 dollar = ? nickels The dollars cancel because dollar/dollar = 1.55 * 20/1 = 104 Do the math.55 dollars = 11 nickels Answer is 11 nickels A. Converting from Grams to Moles and Moles to GramsUsing stoichiometry with chemicals is the same