1. Chapter 10 The Mole

2. The atomic mass is found by checking the periodic table. The atomic mass is the number of grams of an element that is numerically equal to the mass of an atomic mass unit. atomic mass of C = 12.0 g The atomic mass is the mass of one mole of atoms.

3. MOLAR MASS Mole – quantity such that there are as many atoms as in 12 g of carbon The mass of a mole of NaCl is the molar mass. 1 atom 1 mole C 12.0 u 12.0 g Fe 55.8 u 55.8 g Cu 63.5 u 63.5 g

4. MOLAR MASS 1 molecule 1 mole Cl 2 2Cl 2 X 35.5u = 71.0u 71.0 g H 2 O 2H 2 X 1.0u = 2.0u 1O 1 X 16.0u = 16.0u 18.0u 18.0 g

5. MOLAR MASS C 3 H 6 42.0 u 42.0 g per mole Al 2 (SO 4 ) 3 342.3 u 342.3 g per mole

6. Converting grams to moles To convert first write what you are given. Then “times sign draw a line”. Place what you want above the line and the given below the line. “mol” always has a coefficient of 1. Where you see “g”, go to the periodic table to find the value.

7. Ex. 1: How many grams are in 6.50 moles of H 2 SO 4 ? 2H 2 X 1.0 = 2.0g 1S 1 X 32.1 = 32.1g 4 O 4 X 16.0 = 64.0g 98.1g

8. Ex. 2: What is the mass in grams of 5.90 mol C 8 H 18 ? 8C 8 X 12.0 = 96.0g 18H 18 X 1.0 = 18.0g 114.0g

9. Ex. 3: What is the number of moles in 432 g Ba(NO 3 ) 2 ? 1 Ba 1 X 137.3 = 137.3g 2 N 2 X 14.0 = 28.0g 6 O 6 X 16.0 = 96.0g 261.3g