Chemistry:Mole Basics

1. Moles and Stoichiometry Ms. Randall

2. I. Moles WRITE DOWN 1 mole is 6.02 x 1023of anything!! 6.02 x 1023 is called Avogadro's number. A mole can be 6.02 x 1023atoms or molecules A Mole is a Unit Sing-a-long!!!

3. II. Interpreting Chemical Formulas

5. The subscript tells you how many moles of each ion in the compound.

6. Ex. Al2O3 = 2 mol Al+3 3 mol O-2WRITE DOWN

7. WRITE DOWN WRITE DOWN B. Molecular Formula Actual ratios of atoms in a molecule or compound (Ex. C4H10) Molecular formulas are whole-number multiples of an empirical formula Ex: C4H10 molecular formula C2H5 empirical formula

8. C. Structural Formula Shows the arrangement of the atoms in the actual compound WRITE DOWN

9. III. Stoichiometry The study of quantitative relationships that can be derived from chemical formulas and equations WRITE DOWN

10. 1 mole of atoms has a mass equal to the atom’s atomic mass in grams. Atomic mass located on periodic table. Round to the nearest TENTH ( 0.1) Example: C= 12.0 amu = 12.0 g/mol O= 16.0 amu = 16.0 g/mol A. Gram Atomic Mass WRITE DOWN

11. B. Gram Formula Mass (GFM) WRITE DOWN the sum of all the atomic masses in the formula of the substance add up the mass of each atom in the formula. Multiply by the number of each atom if there is more than one of each atom.

12. Example: silver nitrate AgNO3 Element# of atomsMassProduct Ag = 1 × 108amu = 108 g N = 1 × 14amu = 14 g O = 3 × 16 amu = 48 g 170g/mol

13. 11 Regents Practice The gram formula mass of NH4Cl is 22.4 g/mole 28.0 g/mole 53.5 g/mole 95.5 g/mole N 1 x 14.0 = H 4 x 1.0 = Cl 1 x 35.5 = _______ g/mole þ

14. 1. Calculating Moles from Mass Formula on table T in reference table given mass (g) Gram formula mass Mole = WRITE DOWN

15. WRITE DOWN 2. Calculating Grams from Moles given mass (g) Gram formula mass Rearrange the formula in table T to solve for grams Mole = Mole x GFM Grams =

16. Summary Grams Moles ÷ gfm x gfm

17. Example:How many moles are in 390g of calcium chloride? Step1: Find the formula mass of the substance and express it in grams per mole Step 2: Apply the formula CaCl2 Ca = 40 × 1 = 40 Cl = 35 × 2 = 70 110 g/mol grams_ 390g__ mol = mol = GFM 110 g/mol = 3.5 mol

18. What is the mass of 2 moles of sodium thiosulfate? Regents Practice Na2S2O3 Na = 23 × 2 = 46 S = 32 × 2 = 64 O = 16 × 3 = 48 158 g/mol= GFM step 1 grams = moles × GFM = 2 mol × 158 g/mol = 316 g step 2