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HChem
Ch 9 Test: Chemical Quantities
Round final answers to the correct number of significant figures. Balance all equations as necessary.
Show work where indicated.
1. Given the balanced equation 2A + 3B  5C + 4D
If 3.50 moles of A react, how many moles of product C can be formed?
2. Given the balanced equation 2A + 3B  5C + 4D
A chemist wants 2.50 moles of C. How many moles of A are required?
3.
Which statement is true if 12 moles of CO and 12 moles of Fe2O3 are allowed to react?
3CO(g) + Fe2O3(s)  2Fe(s) + 3CO2(g)
a. The limiting reactant is CO and 8.0 mol Fe will be formed.
b. The limiting reactant is Fe2O3 and 24 mol Fe will be formed.
c. The limiting reactant is CO and 3.0 mol CO2 will be formed.
d. The limiting reactant is Fe2O3 and 36 mol CO2 will be formed.
e. There is no limiting reactant. CO and Fe2O3 are present in stoichiometric quantities.
4. Given the chemical equation 2NI3(s)  N2(g) + 3I2(g), which of the following descriptions of the
reaction are correct? Select all correct answers.
a. 1 mole of NI3 decomposes to produce 0.5 moles of N2 and 1.5 moles of I2
b. 2 moles of NI3 decomposes to produce 1 mole of N2 and 3 moles of I2.
c. 4 moles of NI3 decomposes to produce 2 moles of N2 and 12 moles of I2.
d. 2 grams of NI3 decomposes to produce1 gram of N2 and 3 grams of I2.
e. 10 molecules of NI3 decomposes to produce 5 molecules of N2 and 15 molecules of I2.
Examine the reaction below and answer questions 5 and 6:
3 Ag(s) + 4 HNO3  3 AgNO3 + NO(g) + 2H2O
Molar masses:
HNO3 = 63.02 g
AgNO3 = 169.9 g
Ag = 107.9 g
H2O = 18.02 g
NO = 30.01 g
5. The reaction of silver metal and dilute nitric acid proceeds according to the equation above. If 0.10 mole of
powdered silver is added to 0.060 mole of nitric acid, how many moles of AgNO3 can be formed?
6. How many grams of silver(I) nitrate can be prepared from a reaction of 29.0 g of silver with 54.0 grams of
nitric acid?
7. What is the percent yield if the actual yield from the reaction in problem 6 above is 32.5 grams of silver(I)
nitrate?
A
Use the reaction below to answer questions 8 through 11:
____MnO2(s)
+
____Al(g) 
____Mn(s)
+ ____Al2O3(s)
A chemist reacts 60.0 grams of MnO2 with 45.0 grams of aluminum.
8.
Which reactant is limiting?
9.
How many grams of Al2O3 are produced?
Molar masses:
MnO2 = 86.94 g
Al2O3 = 101.96 g
Al = 26.98 g
Mn = 54.94 g
10. How many grams of Mn are produced?
11. If the percent yield of aluminum oxide is 87.5%, what was the actual yield?
Use the reaction below to answer questions 12 through 16:
____H2S(g) + ____O2(g)  ____SO2(g) + ____H2O(l)
12. Write the balanced equation (e.g., 1, 2 ,3 ,4)
13. How many grams of oxygen are required to react with 30.0 grams of H2S?
Molar masses:
H2S = 34.09 g
O2 = 32.00 g
SO2 = 64.07 g
H2O = 18.02 g
14. How many moles of water are produced?
15. How many grams of water are produced?
16. How many molecules of water are produced?
Show all work for the following problem:
Solid copper reacts with silver(I) nitrate to produce copper(II) nitrate and solid silver.
17. If 3.30 kg of copper react with 5.65 kg of silver(I) nitrate, how many kilograms of each product are
produced?