AP Chemistry Homework
Chapter 3—The Mole and Stoichiometry
Answer the following questions in your homework notebook:
1. Indicate whether each of the following statements is true or false, and explain your reasoning:
a. One mole of NH3 weighs more than one mole of H2O.
b. There are more carbon atoms in 48 grams of CO2 than in 12 grams of diamond (pure form of carbon).
c. There are equal numbers of nitrogen atoms in one mole of NH3 and one mole of N2.
d. The number of Cu atoms in 100 grams of Cu(s) is the same as the number of Cu atoms in 100 grams of
copper (II) oxide, CuO.
e. The number of Ni atoms in 100 moles of Ni(s) is the same as the number of Ni atoms in 100 moles of
nickel (II) chloride, NiCl2.
f. There are more hydrogen atoms in 2 moles of NH3 than in 2 moles of CH4.
2. Zinc and iodine react to form zinc iodide. All reactants and products are solids at room temperature.
a. Write a balanced equation for this process (Remember diatomic molecules!).
b. Supposed that 50.0g of zinc and 50.0g of iodine are used to form zinc iodide.
i. Assuming that the reaction goes to completion, which element will be totally consumed in the
formation of the zinc iodide? What is the proper term to refer to this reactant?
ii. How many grams of zinc iodide will be produced from the reaction?
iii. How many grams of the excess element remain unreacted?
iv. What is the % yield if you recovered 42.8g of zinc iodide when you did the reaction in the lab?
3. Acetylene gas, C2H2) is commonly used in high temperature torches.
a. Write a chemical equation for the reaction of acetylene with hydrogen gas to form ethane
(C2H6). Remember diatomic molecules!
b. How many grams of ethane can be produced from a mixture of 30.3g of C2H2 and 4.14 g of
H2?
c. Which reactant is the limiting reactant?
4. How many grams of nitrogen gas can be obtained by reacting 24.5g of NH3 with 30.8g of oxygen gas?
The statement below describes this reaction:
Ammonia reacts with oxygen gas to produce nitrogen gas and water.