Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
|
|
1.
|
The
substances that undergo change in a chemical reaction are called a. | reactants. | c. | coefficients. | b. | products. | d. | elements. | | | | |
|
|
2.
|
Hydrochloric acid, HCl, is added to solid NaOH. After the reaction is complete, NaCl
dissolved in water remains. What are the products of this chemical reaction? a. | NaOH and
HCl | c. | HCl and
NaCl | b. | NaOH and
H2O | d. | NaCl and
H2O | | | | |
|
|
3.
|
Which
of the following does NOT state what the arrow means in a chemical equation? a. | forms | c. | conserves | b. | produces | d. | yields | | | | |
|
|
4.
|
Which
of the following does NOT show the law of conservation of mass? a. | 24 g of Mg burn
in 32 g O2 to produce 56 g of MgO. | b. | 24 mL of Mg burn
in 32 mL O2 to produce 56 mL of MgO. | c. | 2 atoms of Mg
react with 1 molecule of O2 to produce 2 units of MgO. | d. | 1 atom of Mg
reacts with 1 atom of O to produce a unit of MgO that contains 2 atoms. | | |
|
|
5.
|
Which
of the following is a chemical equation that accurately represents what happens when sulfur and
oxygen react to form sulfur trioxide? a. | Sulfur and oxygen react to form sulfur
trioxide. | b. | S and O2 produce
SO3. | c. | S + O2 ® SO3 | d. | 2S +
3O2 ®
2SO3 | | |
|
|
6.
|
Which
of the following is a balanced chemical equation for the synthesis of NaBr from Na and
Br2? a. | Na +
Br2 ® NaBr | b. | 2Na + Br2 ® NaBr | c. | Na +
Br2 ® 2NaBr | d. | 2Na + Br2 ® 2NaBr | | |
|
|
7.
|
Methane, CH4, burns in oxygen gas to form water and carbon dioxide. What is
the correct balanced chemical equation for this reaction? a. | CH4 +
O ® H2O
+ CO2 | b. | CH4 + 4O ® 2H2O + CO2 | c. | CH4 +
O2 ® H2O + CO2 | d. | CH4 +
2O2 ® 2H2O + CO2 | | |
|
|
8.
|
How
many atoms are present in 3 moles of chromium? a. | 6.02 ´ 1023 atoms | c. | 1.80 ´ 1024 atoms | b. | 1.80
´ 1023
atoms | d. | 52.0
atoms | | | | |
|
|
9.
|
How
many grams of CO2 are in 2.1 mol of the compound? a. | 21.0
g | c. | 66.0
g | b. | 44.0
g | d. | 92.4
g | | | | |
|
|
10.
|
How
many moles of He are in 16 g of the element? a. | 1.0 mol | c. | 8.0 mol | b. | 4.0
mol | d. | 16
mol | | | | |
|
|
11.
|
An
industrial process makes calcium oxide by decomposing calcium carbonate. Which of the following is
NOT needed to calculate the mass of calcium oxide that can be produced from 4.7 kg of calcium
carbonate? a. | the balanced
chemical equation | b. | molar masses of the reactants | c. | molar masses of
the product | d. | the volume of the unknown mass | | |
|
|
12.
|
The
coefficients in a balanced chemical equation always can express the ratio of a. | moles of
reactants and products. | b. | volume of reactants and products. | c. | atoms of
reactants and products. | d. | mass of reactants and products. | | |
|
|
13.
|
When
magnesium carbonate, MgCO2, reacts with nitric acid, HNO3, magnesium nitrate
and carbonic acid form. Carbonic acid then breaks down into water and carbon dioxide. Which two types
of reactions take place in this process? a. | synthesis and decomposition | b. | single-replacement and combustion | c. | double-replacement and decomposition | d. | double-replacement and combustion | | |
|
|
14.
|
Which
of the following is NOT always true about a synthesis reaction? a. | One product is
formed. | b. | There is only one reactant. | c. | The general
formula is A + B ® C. | d. | A reactant might be a compound, or it might be an
element. | | |
|
|
15.
|
Which
of the following takes place during a redox reaction? a. | Electrons are
gained only. | b. | Electrons are lost only. | c. | Electrons are
both gained and lost. | d. | Electrons are neither gained nor
lost. | | |
|
|
16.
|
In a
chemical reaction, an iron atom became the ion Fe2+. What happened to the iron
atom? a. | It lost
electrons and was oxidized. | b. | It lost electrons and was reduced. | c. | It gained
electrons and was oxidized. | d. | It gained electrons and was reduced. | | |
|
|
17.
|
In a
compound, chemical energy is contained in the a. | nuclei of the atoms. | c. | bonds. | b. | unbonded
electrons. | d. | movement of the
electrons. | | | | |
|
|
18.
|
Which
of the following statements is true about what happens during a chemical reaction? a. | Bonds of the
reactants are broken, and bonds of the products are formed. | b. | Bonds of the
reactants are formed, and bonds of the products are broken. | c. | The bonds of
both the reactants and the products are broken. | d. | The bonds of
both the reactants and the products are formed. | | |
|
|
19.
|
In
terms of energy, how would you classify the following chemical reaction?
2Cu + O2 ® 2CuO + 315 kJ a. | endothermic | b. | exothermic | c. | both endothermic and exothermic | d. | neither
endothermic nor exothermic | | |
|
|
20.
|
For
the chemical reaction C2H6 + 137 kJ ® C2H4 + H2, the chemical
energy of the a. | reactant is greater than the chemical energy of the
products. | b. | products is greater than the chemical energy of the
reactant. | c. | reactant and the chemical energy of the products are
equal. | d. | reaction is conserved. | | |
|
|
21.
|
The
total amount of energy before and after a chemical reaction is the same. Thus, energy
is a. | created. | c. | conserved. | b. | destroyed. | d. | the same as mass. | | | | |
|
|
22.
|
For
the chemical reaction H2 + CO2 ® H2O + CO, the energy contained in the reactants is
352 kJ, and the energy contained in the products is 394 kJ, assuming 1 mol of each substance is
present. Which of the following statements is true? a. | 42 kJ is
released, and the reaction is exothermic. | b. | 42 kJ is released, and the reaction is
endothermic. | c. | 42 kJ is absorbed, and the reaction is
exothermic. | d. | 42 kJ is absorbed, and the reaction is
endothermic. | | |
|
|
23.
|
Reaction rates do NOT tell you how fast a. | reactants are
being consumed. | b. | products are being formed. | c. | substances are
changing state. | d. | energy is being absorbed or released. | | |
|
|
24.
|
In
general, if the temperature of a chemical reaction is increased, the reaction rate a. | increases. | c. | remains the
same. | b. | decreases. | d. | cannot be predicted. | | | | |
|
|
25.
|
A log
is burning in a fireplace. If the amount of oxygen reaching the log is decreased, which of the
following statements is true? a. | The reaction rate increases. | b. | The reaction
rate decreases. | c. | The reaction rate remains the same. | d. | The reaction
rate depends only on the temperature. | | |
|
|
26.
|
When
the forward and reverse paths of a change occur at the same rate, a. | the system is
conserved. | b. | the system is in equilibrium. | c. | the change must
be physical. | d. | the change must be chemical. | | |
|
|
27.
|
The
equation 2NO2 « N2O4 shows a system a. | in chemical
equilibrium. | b. | in physical equilibrium. | c. | that does not
reach equilibrium. | d. | that does not change. | | |
|
|
28.
|
What
happens to the reaction 2NO2 «N2O4+ 57.2 kJ when the temperature of the
reaction is increased? a. | More reactant is formed. | b. | More product is
formed. | c. | No change occurs in the amounts of reactant and product
present. | d. | The effect depends on whether or not a catalyst is
present. | | |
|
|
29.
|
The
reaction H2CO3 + H2O « H3O+ + HCO3
takes place in water. What happens to the equilibrium when the pressure is
increased? a. | It favors
formation of reactants. | b. | It favors formation of products. | c. | It does not
change. | d. | It is conserved. | | |
|
|
|
Figure
7-1
|
|
30.
|
The
reaction in Figure 7-1 shows the formation of ammonia from nitrogen and hydrogen in the Haber
process. What will be the effect on the equilibrium if the temperature is increased and some of the
ammonia is removed from the system? a. | More ammonia will definitely form. | b. | More reactants
will definitely form. | c. | The changes definitely will have no overall effect on the
reaction. | d. | Any effect will depend on the amount of change of temperature
and concentration. | | |
|