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Chapter 8, Chemical Equations and Reactions


Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

1. 
Knowledge about what products are produced in a chemical reaction is obtained by
a.
inspecting the chemical equation.
c.
laboratory analysis.
b.
balancing the chemical equation.
d.
writing a word equation.
 

2. 
A chemical reaction has NOT occurred if the products have
a.
the same mass as the reactants.
b.
less total bond energy than the reactants.
c.
more total bond energy than the reactants.
d.
the same chemical properties as the reactants.
 

3. 
Which observation does NOT indicate that a chemical reaction has occurred?
a.
formation of a precipitate
c.
evolution of heat and light
b.
production of a gas
d.
change in total mass of substances
 

4. 
A solid produced by a chemical reaction in solution that separates from the solution is called
a.
a precipitate.
c.
a molecule.
b.
a reactant.
d.
the mass of the product.
 

5. 
After the correct formula for a reactant in an equation has been written, the
a.
subscripts are adjusted to balance the equation.
b.
formula should not be changed.
c.
same formula must appear as the product.
d.
symbols in the formula must not appear on the product side of the equation.
 

6. 
In writing an equation that produces hydrogen gas, the correct representation of hydrogen gas is
a.
H.
c.
H2.
b.
2H.
d.
OH.
 

7. 
What is the small whole number that appears in front of a formula in a chemical equation?
a.
a subscript
c.
a ratio
b.
a superscript
d.
a coefficient
 

8. 
To balance a chemical equation, it may be necessary to adjust the
a.
coefficients.
c.
formulas of the products.
b.
subscripts.
d.
number of products.
 

9. 
According to the law of conservation of mass, the total mass of the reacting substances is
a.
always more than the total mass of the products.
b.
always less than the total mass of the products.
c.
sometimes more and sometimes less than the total mass of the products.
d.
always equal to the total mass of the products.
 

10. 
A chemical equation is balanced when the
a.
coefficients of the reactants equal the coefficients of the products.
b.
same number of each kind of atom appears in the reactants and in the products.
c.
products and reactants are the same chemicals.
d.
subscripts of the reactants equal the subscripts of the products.
 

11. 
Which word equation represents the reaction that produces water from hydrogen and oxygen?
a.
Water is produced from hydrogen and oxygen.
b.
Hydrogen plus oxygen yields water.
c.
H2 + O2 ® water.
d.
Water can be separated into hydrogen and oxygen.
 

12. 
How would oxygen be represented in the formula equation for the reaction of methane and oxygen to yield carbon dioxide and water?
a.
oxygen
c.
O2
b.
O
d.
O3
 

13. 
Which of the following is a formula equation for the formation of carbon dioxide from carbon and oxygen?
a.
Carbon plus oxygen yields carbon dioxide.
b.
C + O2 ® CO2
c.
CO2 ® C + O2
d.
2C + O ® CO2
 

14. 
For the formula equation 2Mg + O2 ® 2MgO, the word equation would begin
a.
Manganese plus oxygen . . .
c.
Magnesium plus oxygen . . .
b.
Molybdenum plus oxygen . . .
d.
Heat plus oxygen . . .
 

15. 
In an equation, the symbol for a substance in water solution is followed by
a.
(1).
c.
(aq).
b.
(g).
d.
(s).
 

16. 
A chemical formula written over the arrow in a chemical equation signifies
a.
a byproduct.
c.
a catalyst for the reaction.
b.
the formation of a gas.
d.
an impurity.
 

17. 
Which coefficients correctly balance the formula equation NH4NO2(s)® N2(g) + H2O(l)?
a.
1, 2, 2
c.
2, 1, 1
b.
1, 1, 2
d.
2, 2, 2
 

18. 
Which coefficients correctly balance the formula equation CaO + H2O ® Ca(OH)2?
a.
2, 1, 2
c.
1, 2, 1
b.
1, 2, 3
d.
1, 1, 1
 

19. 
After the first steps in writing an equation, the equation is balanced by
a.
adjusting subscripts to the formula(s).
b.
adjusting coefficients to the smallest whole-number ratio.
c.
changing the products formed.
d.
making the number of reactants equal to the number of products.
 

20. 
The complete balanced equation for the reaction between zinc hydroxide and acetic acid is
a.
ZnOH + CH3COOH ® ZnCH3COO + H2O.
b.
Zn(OH)2 + CH3COOH ® Zn + 2CO2 +3H2O.
c.
Zn(OH)2 + 2CH3COOH ® Zn(CH3COO)2 + 2H2O.
d.
Zn(OH)2 + 2CH3COOH ® Zn(CH3COO)2 + H2 + O2.
 

21. 
What is the balanced equation for the combustion of sulfur?
a.
S(s) + O2(g) ® SO(g)
c.
2S(s) + 3O2(g) ® SO3(s)
b.
S(s) + O2(g) ® SO2(g)
d.
S(s) + 2O2(g) ® SO42–(aq)
 

22. 
In what kind of reaction do two or more substances combine to form a new compound?
a.
decomposition reaction
c.
double-replacement reaction
b.
ionic reaction
d.
synthesis reaction
 

23. 
The equation AX ® A + X is the general equation for a
a.
synthesis reaction.
c.
combustion reaction.
b.
decomposition reaction.
d.
single-replacement reaction.
 

24. 
In what kind of reaction does one element replace a similar element in a compound?
a.
single-replacement reaction
c.
decomposition reaction
b.
double-replacement reaction
d.
ionic reaction
 

25. 
The equation AX + BY ® AY + BX is the general equation for a
a.
synthesis reaction.
c.
single-replacement reaction.
b.
decomposition reaction.
d.
double-replacement reaction.
 

26. 
The equation A + X ® AX is the general equation for a(n)
a.
combustion reaction.
c.
synthesis reaction.
b.
ionic reaction.
d.
double-replacement reaction.
 

27. 
In what kind of reaction does a single compound produce two or more simpler substances?
a.
decomposition reaction
c.
single-replacement reaction
b.
synthesis reaction
d.
ionic reaction
 

28. 
The equation A + BX ® AX + B is the general equation for a
a.
double-replacement reaction.
c.
single-replacement reaction.
b.
decomposition reaction.
d.
combustion reaction.
 

29. 
In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two new compounds?
a.
synthesis reaction
c.
decomposition reaction
b.
double-replacement reaction
d.
combustion reaction
 

30. 
The reaction 2Mg(s) + O2(g) ® 2MgO(s) is a
a.
synthesis reaction.
c.
single-replacement reaction.
b.
decomposition reaction.
d.
double-replacement reaction.
 

31. 
The reaction Mg(s) + 2HCl(aq) ® H2(g) + MgCl2(aq) is a
a.
composition reaction.
c.
single-replacement reaction.
b.
decomposition reaction.
d.
double-replacement reaction.
 

32. 
The reaction 2HgO(s) ® 2Hg(l) + O2(g) is a(n)
a.
single-replacement reaction.
c.
ionic reaction.
b.
synthesis reaction.
d.
decomposition reaction.
 

33. 
The reaction Pb(NO3)2(aq) + 2KI(aq) ® PbI2(s) + 2KNO3(aq) is a
a.
double-replacement reaction.
c.
decomposition reaction.
b.
synthesis reaction.
d.
combustion reaction.
 

34. 
The reaction 2KClO3(s) ® 2KCl(s) + 3O2(g) is a(n)
a.
synthesis reaction.
c.
combustion reaction.
b.
decomposition reaction.
d.
ionic reaction.
 

35. 
In one type of synthesis reaction, an element combines with oxygen to yield a(n)
a.
acid.
c.
oxide.
b.
hydroxide.
d.
metal.
 

36. 
The decomposition of a substance by an electric current is called
a.
electrolysis.
c.
ionization.
b.
conduction.
d.
transformation.
 

37. 
When heated, a metal carbonate decomposes into a metal oxide and
a.
carbon.
c.
oxygen.
b.
carbon dioxide.
d.
hydrogen.
 

38. 
Oxides of active metals, such as CaO, react with water to produce
a.
metal carbonates.
c.
acids.
b.
metal hydrides.
d.
metal hydroxides.
 

39. 
An active metal and a halogen react to form a(n)
a.
salt.
c.
acid.
b.
hydroxide.
d.
oxide.
 

40. 
When a binary compound decomposes, what is produced?
a.
an oxide
c.
a tertiary compound
b.
an acid
d.
two elements
 

41. 
Many metal hydroxides decompose when heated to yield metal oxides and
a.
metal hydrides.
c.
carbon dioxide.
b.
water.
d.
an acid.
 

42. 
When a metal chlorate is heated, it decomposes to yield a metal chloride and
a.
a metal oxide.
c.
hydrogen.
b.
a metal hydroxide.
d.
oxygen.
 

43. 
Some acids, such as carbonic acid, decompose to nonmetal oxides and
a.
water.
c.
oxygen.
b.
a salt.
d.
peroxide.
 

44. 
When heated, metallic chlorates decompose into
a.
metallic oxides and chlorine.
b.
metallic chlorides and oxygen.
c.
a metal and a compound of chlorine and oxygen.
d.
a metal, chlorine, and oxygen.
 

45. 
In the equation 2Al(s) + 3Fe(NO3)2(aq) ® 3Fe(s) + 2Al(NO3)3(aq), iron has been replaced by
a.
nitrate.
c.
aluminum.
b.
water.
d.
nitrogen.
 

46. 
Group 1 metals react with water to produce metal hydroxides and
a.
metal hydroxides.
c.
oxygen.
b.
hydrochloric acid.
d.
hydrogen.
 

47. 
The replacement of bromine by chlorine in a salt is an example of a single-replacement reaction by
a.
halogens.
c.
water.
b.
sodium.
d.
electrolysis.
 

48. 
When a slightly soluble solid compound is produced in a double-replacement reaction, a
a.
gas bubbles off.
c.
combustion reaction takes place.
b.
precipitate is formed.
d.
halogen is produced.
 

49. 
An insoluble gas that forms in a double-replacement reaction in aqueous solution
a.
bubbles out of solution.
c.
disassociates into ions.
b.
forms a precipitate.
d.
reacts with the water.
 

50. 
In a double-replacement reaction, hydrogen chloride and sodium hydroxide react to produce sodium chloride. Another product is
a.
sodium hydride.
c.
water.
b.
potassium chloride.
d.
hydrogen gas.
 

51. 
Active metals react with certain acids, such as hydrochloric acid, to yield a metal compound and
a.
oxygen.
c.
chlorine.
b.
hydrogen.
d.
sodium.
 

52. 
Some metals, such as iron, react with steam to produce hydrogen gas and a
a.
metal hydroxide.
c.
metallic acid.
b.
metal hydride.
d.
metal oxide.
 

53. 
When potassium reacts with water, one product formed is
a.
hydrogen gas.
c.
potassium oxide.
b.
oxygen gas.
d.
salt.
 

54. 
A precipitate forms in a double-replacement reaction when
a.
hydrogen gas reacts with a metal.
c.
water boils out of the solution.
b.
positive ions combine with negative ions.
d.
a gas escapes.
 

55. 
The reaction of calcium oxide (CaO) with water yields
a.
calcium and oxygen gas.
c.
calcium and a salt.
b.
calcium hydroxide.
d.
carbon dioxide and water.
 

56. 
Predict the product of the following reaction: MgO + CO2 ®
a.
MgCO3
c.
MgC + O3
b.
Mg + CO3
d.
MgCO2 + O
 

57. 
Magnesium hydroxide decomposes to yield magnesium oxide and
a.
hydrogen.
c.
water.
b.
oxygen.
d.
salt.
 

58. 
When sodium chlorate (NaClO3) decomposes, the products are
a.
sodium hydroxide and water.
c.
sodium and chlorine oxide.
b.
sodium oxide and chlorine.
d.
sodium chloride and oxygen.
 

59. 
If chlorine gas is produced by halogen replacement, the other halogen in the reaction must be
a.
bromine.
c.
astatine.
b.
iodine.
d.
fluorine.
 

60. 
The formulas for the products of the reaction between sodium hydroxide and sulfuric acid are
a.
Na2SO4 and H2O.
c.
SI4 and Na2O.
b.
NaSO4 and H2O.
d.
S + O2 and Na.
 

61. 
The ability of an element to react is the element's
a.
valence.
c.
stability.
b.
activity.
d.
electronegativity.
 

62. 
What is the name of a list of elements arranged according to the ease with which they undergo certain chemical reactions?
a.
reactivity list
c.
activity series
b.
reaction sequence
d.
periodic list
 

63. 
An element in the activity series can replace any element
a.
in the periodic table.
c.
above it on the list.
b.
below it on the list.
d.
in its group.
 

64. 
What can be predicted by using an activity series?
a.
whether a certain chemical reaction will occur
b.
the amount of energy released by a chemical reaction
c.
the electronegativity values of elements
d.
the melting points of elements
 

65. 
The activity series of metals indicates the ease with which metal
a.
atoms gain neutrons.
c.
atoms form covalent bonds.
b.
nuclei fuse.
d.
atoms lose electrons.
 

66. 
If metal X is lower than metal Y in the activity series, then metal X
a.
replaces ions of metal Y in a solution.
b.
loses electrons more readily than does metal Y.
c.
loses electrons less readily than does metal Y.
d.
forms positive ions more readily than does metal Y.
 

67. 
If a certain metal is placed in an ionic solution containing another metal and no reaction occurs, then the metal originally in the solution is
a.
a halogen.
c.
not on the activity series.
b.
higher on the activity series.
d.
unreactive.
 

68. 
Predict what happens when calcium metal is added to a solution of magnesium chloride.
a.
No reaction occurs.
c.
Magnesium calcite forms.
b.
Calcium chloride forms.
d.
Gaseous calcium is produced.
 

69. 
Predict what happens when zinc is added to water.
a.
No reaction occurs.
c.
Zinc oxide forms.
b.
Steam is produced.
d.
Hydrogen is released.
 

70. 
Predict what happens when lead is added to nitric acid.
a.
No reaction occurs.
c.
Lead oxide forms.
b.
Oxygen is released.
d.
Hydrogen is released.
 

71. 
Predict what happens when nickel is added to a solution of potassium chloride.
a.
No reaction occurs.
c.
Potassium nickel chloride forms.
b.
Nickel chloride forms.
d.
Hydrochloric acid forms.
 

72. 
Magnesium bromide + chlorine yield
a.
Mg and BrCl.
c.
MgBrCl.
b.
MgCl and Br2.
d.
Mg(Cl)2 and Br2.
 

73. 
Which reaction does NOT occur?
a.
2HF + Cl2 ® F2 + 2HCl
c.
Fe + CuCl2 ® FeCl2 + Cu
b.
2Na + ZnF2 ® 2NaF + Zn
d.
2HCl + Mg ® MgCl2 + H2
 

74. 
Which reaction can be predicted from the activity series?
a.
2Cl ® Cl2
c.
2HCl + 2Na ® 2NaCl + H2
b.
HCl + NaOH ® NaCl + H2O
d.
Cl2 ® 2Cl
 

Short Answer
 

75. 
When a glass blower shapes molten glass into an ornament, does a chemical reaction occur? Explain.
 



 
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