1. Ethylene glycol is used as automobile antifreeze. 6.38 g of this compound contains 2.47 g of carbon and 0.620 g of hydrogen. The rest is oxygen. The molar mass is 62.0 g/mole. What are the empirical and molecular formulas of ethylene glycol?
2. Aspirin is produced in a student lab. One mole of salicylic acid (MM 138 g/mole) reacts with one mole of acetic anhydride (MM 102 g/mole), producing one mole of aspirin (MM 180 g/mole) and one mole of acetic acid, commonly known as vinegar (MM 60 g/mole). The student reacts 2.054 g of salicylic acid with 5.00 mL (density 1.00 g/mL) of acetic anhydride. After heating, crystallizing, and filtering, the collected product weighed 2.189 g.
a. Write a balanced chemical equation in words.
b. Which one is the limiting reagent?
c. How much is the theoretical yield?
d. How much is the percent yield?
3. A cup of ice cream contains 6.0 g of protein, 36 g of carbohydrate, and 8.0 g of fat. Approximately how many hours of walking would be required to burn up the energy taken in by eating a cup of ice cream?
Protein = 4 kcal/g
Carbohydrate = 4 kcal/g
Fat = 9 kcal/g
Walking burns 300 kcal/hr
This solution answers several questions related to biological chemistry.