Ch3
Practice Test
MULTIPLE CHOICE
Section 3.1 Balancing Chemical Equations
1. What is the sum of the coefficients when the following equation
is balanced using the lowest, whole numbered coefficients?
_____ B2O3(s) +
_____ HF(l) ---> ____ BF3(g) + _____
H2O(l)
a) 8
b) 11
c) 15
d) none of these
2. Aluminum metal reacts with iron(II) sulfide to form aluminum
sulfide and iron metal. What is the coefficient for aluminum when the
equation is balanced using the lowest, whole-numbered
coefficients?
a) 1
b) 2
c) 3
d) 4
Section 3.3 Avogadro's Number and the Mole
3. How many grams does a single chlorine molecule, Cl2,
weigh?
a) 5.887 x 10-23 g
b) 1.177 x 10-22g
c) 35.45 g
d) 70.90 g
4. How many molecules are there in 5.00 g of FeSO4?
a) 5.46 x 10-26 molecules
b) 1.98 x 1022molecules
c) 1.83 x 1025 molecules
d) 4.58 x 1026 molecules
5. What is the identity of substance X if 0.380 mol of X weighs
17.5 g?
a) NO2
b) NO3
c) N2O
d) N2O4
Section 3.4 Stoichiometry: Chemical Arithmetic
6. Dinitrogen monoxide gas decomposes to form nitrogen gas and
oxygen gas. How many grams of oxygen are formed when 5.00 g of
dinitrogen monoxide decomposes?
a) 0.909 g
b) 1.82 g
c) 3.64 g
d) 7.27 g
Section 3.5 Yields of Chemical Reactions
7. If the percent yield is 75% and 45 g of NO2 are used
in the following reaction, how many grams of nitric acid are
produced?
3 NO2(g) + H2O(l) --->
2 HNO3(aq) + NO(g)
a) 30.8 g
b) 41.1 g
c) 54.8 g
d) 69.3 g
Section 3.6 Reactions with Limiting Amounts of Reactants
8. Which substance is the limiting reagent when 2.0 g of sulfur
reacts with 3.0 g of oxygen and 4.0 g of sodium hydroxide according
to the following reaction:
2 S(s) + 3 O2(g) + 4 NaOH(aq) ---> 2
Na2SO4(aq) + 2 H2O(l)
a) S
b) O2
c) NaOH
d) all react equally
Section 3.7 Concentrations of Reactants in Solution: Molarity
9. A solution is 0.540 M NaOH. What volume contains 15.5 g of
NaOH?
a) 0.202 L
b) 0.718 L
c) 1.15 L
d) 1.40 L
10. What is the concentration of an AlCl3 solution if
150. mL of solution contains 250. mg of Cl- ion?
a) 1.57 x 10-2M
b) 3.75 x 10-4 M
c) 4.70 x 10-4 M
d) 1.41 x 10-3 M
Section 3.8 Diluting Concentrated Solutions
11. A student prepared a stock solution by dissolving 20.0 g of
KOH in enough water to make 150. mL of solution. He took 15.0 mL of
the diluted solution and added another 50.0 mL of deionized water.
What is the concentration of the final solution?
a) 0.548 M
b) 0.713 M
c) 1.03 M
d) 1.66 M
Section 3.11 Percent Composition and Empirical Formulas
12. What is the empirical formula for perfluoropropane if the
compound contains 81% fluorine and 19% carbon by mass?
a) CF3
b) C2F8
c) C3F8
d) C19F81
Section 3.12 Determining Empirical Formulas: Elemental Analysis
13. Combustion analysis of 1.500 g unknown compound containing
only carbon and hydrogen produced 4.554 g of CO2 and 2.322
g of H2O. What is the empirical formula of the
compound?
a) CH2
b) C2H5
c) C4H10
d) C5H2