Reference no: EM132508864

1. An old (pre-1987) penny is nearly pure copper. If such a penny has a mass of 3.3 g, how many moles of copper would be in one penny? (0.052 mol Cu)

2. Four iron nails have a total mass of 4.42 grams. How many moles of iron do they contain? (0.0792 mol Fe)

3. What mass of water would you need to have 15.0 moles of H2O? (270. g H2O)

4. One box of Morton's Salt contains 737 grams. How many moles of sodium chloride is this? (12.6 mol NaCl)

5. A chocolate chip cookie recipe calls for 0.050 moles of baking soda (sodium bicarbonate, NaHCO3). How many grams should the chef mass out? (4.2 g NaHCO3)

6. What volume will 2.00 moles of N2 occupy at STP? (44.8 L N2)

7. First-century Roman doctors believed that urine whitened teeth and also kept them firmly in place. As gross as that sounds, it must have worked because it was used as an active ingredient in toothpaste and mouthwash well into the 18th century. Would you believe it's still used today? Thankfully, not in its original form! Modern dentists recognized that it was the ammonia that cleaned the teeth, and they still use that. The formula for ammonia is NH3.

a. How many moles are in 0.75 g of ammonia? (0.044 mol NH3)

b. How many molecules is this? (2.6 x 1023 molecules NH3)

c. Ammonia is a gas at room temperature. What is the volume of the ammonia in part a at STP? (0.98 L NH3)

8. Lead (II) chromate, PbCrO4, was used as a pigment in paints. How many moles of lead chromate are in 75.0 g of lead (II) chromate? (0.232 mol PbCrO4)

9. What is the volume of 25.0 g of CO2 gas at STP? (12.7 L CO2)