AP Chem Stoichiometry Quiz
Chemist__________________________
Multiple choice – choose the best answer
1. What is the simplest formula for a compound composed of only carbon and hydrogen and containing
14.3 % H by mass?
a. CH
b. CH4
c. C4H
d. CH2
e. CH3
2. What is the molar mass of Al(NO3) 3?
a. 165.0
b. 56.99
c. 213.0
d. 88.99
e. 185.0
3. In the reaction below, how many moles of Aluminum will produce 1 mol of iron?
8 Al + 3Fe3O4  9Fe + 4 Al2O3
a. 1
b. ¾
c. 9/8
d. 8/9
e. 4/3
4. A substance has an empirical formula of CH2. Its molar mass is found by experiment to be 83.5. What is
the likely molecular formula for the compound?
a. C2H4
b. C6H2
c. C4H2
d. CH12
e. C6H12
5. What is the percentage of potassium in K3PO4?
a. 14.6%
b. 29.2%
c. 18.4%
d. 55.2%
e. 39.1%
6. A 0.200 gram sample of a compound containing only carbon, hydrogen and oxygen is burned, yielding
0.357 g of CO2 and 0.146g of H20. What is the percentage of carbon by mass in this compound?
a. 56.0%
b. 73.0%
c. 48.7%
d. 24.3%
e. 43.2%
7. In the reaction:
2AgNO3 + CaCl2  2AgCl + Ca(NO3) 2
how many grams of AgCl
(molar mass 143.5) will precipitate when 20.0g AgNO3 (molar mass 170) is reacted with 15.0 g CaCl2
(molar mass 111)
a. 16.9
b. 38.8
c. 33.8
d. 8.45
e. 67.6
8. Determine the empirical formula for a compound that is 25% hydrogen and 75% carbon.
a. CH
b. CH2
c. CH4
d. C2H8
e. C4H
9. A sample of a hydrate of BaCl2 with a mass of 61 grams was heated until all the water was removed.
The sample was then weighed and found to have a mass of 52 grams. What is the formula for the
hydrate?
a. BaCl2·5H20
b. BaCl2·4H20
c. BaCl2·3H20
d. BaCl2·2H20
e. BaCl2·H20
10. One mole of solid zinc has a mass of 65.39 of these.
a. moles
b. liters
c. grams
d. atmospheres
e. volts
23
11. These units can be calculated by dividing a quantity by 6.02 x 10 .
a. moles
b. liters
c. grams
d. atmospheres
e. volts
12. What is the mass of oxygen in 148 grams of calcium hydroxide, Ca(OH)2?
a. 16 g
b. 24 g
c. 32 g
d. 48 g
e. 64 g
13. Methane (CH4) is burned in the presence of oxygen to yield carbon dioxide and water. If you write the
balanced equation for this reaction, what is the coefficient in front of the oxygen?
a. 1
b. 2
c. 3
d. 4
e. 8
14. Methane is burned in the presence of oxygen to yield carbon dioxide and water. How many moles of
water are produced burning 5 moles of methane in air (unlimited oxygen)?
a. 2.5
b. 5
c. 10
d. 20
e. 2
15. What is the name of the compound HNO3?
a. hydronitrous acid
b. nitrous acid
c. nitric acid
d. hydronitric acid
16. What if the correct formula for Copper (II) nitrate?
a. CuN
b. Cu3N2
c. CuNO3
d. Cu(NO3) 2
e. Cu2NO3
17. How many significant figures are in the number 0.00423050?
a. 4
b. 5
c. 6
d. 8
e. 9
18. Which of the following is equivalent to 5.60 x 10-4?
a. 56000
b. 56000.
c. 0.00056
d. 0.000560
e. 5.60
Chemist:_______________________________
Open Response – Please show all work and include units throughout the problem, when appropriate.
1. Maleic acid is an organic compound composed of 41.39 % C, 3.47 % H and the rest oxygen. If 0.129 mol of
maleic acid has a mass of 15.0 g, what are the empirical and molecular formulas of maleic acid?
2. Consider the reaction H2 + O2  H20
5.00 grams of hydrogen gas are reacted with 56.00 grams of oxygen gas.
a. Balance the equation.
b. Find the limiting reagent.
c. Find the theoretical yield of water for this process.
3. Consider the following unbalanced chemical reaction:
P4 + F2  PF3
How many grams of F2 are needed to produce 120 grams of PF3 is the reaction has a 78.1 % yield?