Question 1

The number of moles of atomic oxygen in 2 moles of Ca3PO4)2 is

Accepted Answer

A)  2. 
B)  4. 
C)  8. 
D)  16. 
A)  2. 
B)  4. 
C)  8. 
D)  16.

Question 2

In the electrolysis of molten NaCl, the substance liberated at the positive electrode is

Accepted Answer

A)  Cl-. 
B)  Cl2. 
C)  Na+. 
D)  Na. 
A)  Cl-. 
B)  Cl2. 
C)  Na+. 
D)  Na.

Question 3

When sodium and chlorine react to form sodium chloride NaCl), 411 kJ per mole of NaCl is given off. To break up 1 mole of NaCl into sodium and chlorine requires

Accepted Answer

A)  less than 411 kJ. 
B)  411 kJ. 
C)  more than 411 kJ. 
D)  any of the above, depending on the circumstances. 
A)  less than 411 kJ. 
B)  411 kJ. 
C)  more than 411 kJ. 
D)  any of the above, depending on the circumstances.

Question 4

The time needed for a strong acid to neutralize a strong base in solution

Accepted Answer

A)  decreases with temperature. 
B)  increases with temperature. 
C)  is virtually independent of temperature. 
D)  Any of these choices could be correct, depending on the particular acid and base. 
A)  decreases with temperature. 
B)  increases with temperature. 
C)  is virtually independent of temperature. 
D)  Any of these choices could be correct, depending on the particular acid and base.

Question 5

At ordinary temperatures, the temperature increase needed to double the rate of many common chemical reactions is

Accepted Answer

A)  1°C. 
B)  10°C. 
C)  50°C. 
D)  100°C. 
A)  1°C. 
B)  10°C. 
C)  50°C. 
D)  100°C.

Question 6

Of the following battery types, the one with the highest energy density is

Accepted Answer

A)  lead-acid. 
B)  lithium-ion. 
C)  nickel-cadmium. 
D)  nickel-metal-hydride. 
A)  lead-acid. 
B)  lithium-ion. 
C)  nickel-cadmium. 
D)  nickel-metal-hydride.

Question 7

Plants cannot make use of atmospheric nitrogen to form proteins because the atoms in a nitrogen molecule are held together by

Accepted Answer

A)  single bonds 
B)  double bonds 
C)  triple bonds 
D)  quadruple bonds 
A)  single bonds 
B)  double bonds 
C)  triple bonds 
D)  quadruple bonds

Question 8

The proportion of oxygen in dry air is about

Accepted Answer

A)  1/5. 
B)  1/3. 
C)  1/2. 
D)  4/5. 
A)  1/5. 
B)  1/3. 
C)  1/2. 
D)  4/5.

Question 9

The number of moles of H2O formed when 1 mole of O2 reacts with C5H12 in the reaction C5H12 + 8O2 → 5CO2 + 6H2O is

Accepted Answer

A)  3/4. 
B)  4/3. 
C)  6. 
D)  8. 
A)  3/4. 
B)  4/3. 
C)  6. 
D)  8.

Question 10

The atomic mass of N is 14 u and that of Ca is 40 u. The proportion of N by mass in the compound Ca3N2 is

Accepted Answer

A)  19 percent. 
B)  35 percent. 
C)  40 percent. 
D)  81 percent. 
A)  19 percent. 
B)  35 percent. 
C)  40 percent. 
D)  81 percent.

Question 11

Sulfur has an atomic mass of 32 u and Avogadro's number is 6 × 1023 formula units/mole. The number of sulfur atoms in 1 g of sulfur is

Accepted Answer

A)  32. 
B)  1.9 × 1022. 
C)  6 × 1023. 
D)  1.9 × 1025. 
A)  32. 
B)  1.9 × 1022. 
C)  6 × 1023. 
D)  1.9 × 1025.

Question 12

The number of formula units in a mole of a substance

Accepted Answer

A)  depends on the formula mass of the substance. 
B)  depends on whether the substance is an element or a compound. 
C)  depends on whether the substance is a gas, a liquid, or a solid. 
D)  is the same for all substances. 
A)  depends on the formula mass of the substance. 
B)  depends on whether the substance is an element or a compound. 
C)  depends on whether the substance is a gas, a liquid, or a solid. 
D)  is the same for all substances.

Question 13

When a gas reaction involves an increase in the number of molecules present, the yield can be increased by

Accepted Answer

A)  increasing the pressure. 
B)  decreasing the pressure. 
C)  increasing the temperature. 
D)  decreasing the temperature. 
A)  increasing the pressure. 
B)  decreasing the pressure. 
C)  increasing the temperature. 
D)  decreasing the temperature.

Question 14

When a substance loses electrons in a chemical reaction, the substance is said to be

Accepted Answer

A)  reduced. 
B)  oxidized. 
C)  dissociated. 
D)  activated. 
A)  reduced. 
B)  oxidized. 
C)  dissociated. 
D)  activated.

Question 15

When a hydrogen fuel cell produces an electric current,

Accepted Answer

A)  it must be recharged periodically. 
B)  it must be heated. 
C)  it must have hydrogen added to it continuously. 
D)  it gives off carbon dioxide. 
A)  it must be recharged periodically. 
B)  it must be heated. 
C)  it must have hydrogen added to it continuously. 
D)  it gives off carbon dioxide.

Question 16

The decomposition of an unstable compound usually

Accepted Answer

A)  occurs only at low temperatures. 
B)  requires a catalyst to occur. 
C)  is endothermic. 
D)  is exothermic. 
A)  occurs only at low temperatures. 
B)  requires a catalyst to occur. 
C)  is endothermic. 
D)  is exothermic.

Question 17

Chemical reactions in solution do not depend to any great extent upon

Accepted Answer

A)  pressure. 
B)  temperature. 
C)  concentration. 
D)  catalysts. 
A)  pressure. 
B)  temperature. 
C)  concentration. 
D)  catalysts.

Question 18

Oxidation-reduction reactions are not involved in

Accepted Answer

A)  electrolysis. 
B)  acid-base neutralization. 
C)  the operation of a storage battery. 
D)  the operation of a fuel cell. 
A)  electrolysis. 
B)  acid-base neutralization. 
C)  the operation of a storage battery. 
D)  the operation of a fuel cell.

Question 19

Reaction rates increase with temperature mainly because a rise in temperature increases

Accepted Answer

A)  the number of ions. 
B)  the number of polar molecules. 
C)  the number of activated molecules. 
D)  the average length of time between molecular collision. 
A)  the number of ions. 
B)  the number of polar molecules. 
C)  the number of activated molecules. 
D)  the average length of time between molecular collision.

Question 20

Most chemical reactions

Accepted Answer

A)  absorb energy. 
B)  occur at rates that are independent of temperature. 
C)  are reversible. 
D)  produce precipitates. 
A)  absorb energy. 
B)  occur at rates that are independent of temperature. 
C)  are reversible. 
D)  produce precipitates.

The number of moles of atomic oxygen in 2 moles of Ca₃PO₄)₂ is

In the electrolysis of molten NaCl, the substance liberated at the positive electrode is

When sodium and chlorine react to form sodium chloride NaCl), 411 kJ per mole of NaCl is given off. To break up 1 mole of NaCl into sodium and chlorine requires

The time needed for a strong acid to neutralize a strong base in solution

At ordinary temperatures, the temperature increase needed to double the rate of many common chemical reactions is

Of the following battery types, the one with the highest energy density is

Plants cannot make use of atmospheric nitrogen to form proteins because the atoms in a nitrogen molecule are held together by

The proportion of oxygen in dry air is about

The number of moles of H₂O formed when 1 mole of O₂ reacts with C₅H₁₂ in the reaction C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O is

The atomic mass of N is 14 u and that of Ca is 40 u. The proportion of N by mass in the compound Ca₃N₂ is

Sulfur has an atomic mass of 32 u and Avogadro's number is 6 × 10²³ formula units/mole. The number of sulfur atoms in 1 g of sulfur is

The number of formula units in a mole of a substance

When a gas reaction involves an increase in the number of molecules present, the yield can be increased by

When a substance loses electrons in a chemical reaction, the substance is said to be

When a hydrogen fuel cell produces an electric current,

The decomposition of an unstable compound usually

Chemical reactions in solution do not depend to any great extent upon

Oxidation-reduction reactions are not involved in

Reaction rates increase with temperature mainly because a rise in temperature increases

Most chemical reactions

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Exam 12: Chemical Reactions

The number of moles of atomic oxygen in 2 moles of Ca3PO4)2 is

In the electrolysis of molten NaCl, the substance liberated at the positive electrode is

When sodium and chlorine react to form sodium chloride NaCl), 411 kJ per mole of NaCl is given off. To break up 1 mole of NaCl into sodium and chlorine requires

The time needed for a strong acid to neutralize a strong base in solution

At ordinary temperatures, the temperature increase needed to double the rate of many common chemical reactions is

Of the following battery types, the one with the highest energy density is

Plants cannot make use of atmospheric nitrogen to form proteins because the atoms in a nitrogen molecule are held together by

The proportion of oxygen in dry air is about

The number of moles of H2O formed when 1 mole of O2 reacts with C5H12 in the reaction C5H12 + 8O2 → 5CO2 + 6H2O is

The atomic mass of N is 14 u and that of Ca is 40 u. The proportion of N by mass in the compound Ca3N2 is

Sulfur has an atomic mass of 32 u and Avogadro's number is 6 × 1023 formula units/mole. The number of sulfur atoms in 1 g of sulfur is

The number of formula units in a mole of a substance

When a gas reaction involves an increase in the number of molecules present, the yield can be increased by

When a substance loses electrons in a chemical reaction, the substance is said to be

When a hydrogen fuel cell produces an electric current,

The decomposition of an unstable compound usually

Chemical reactions in solution do not depend to any great extent upon

Oxidation-reduction reactions are not involved in

Reaction rates increase with temperature mainly because a rise in temperature increases

Most chemical reactions

The Scientific Method

Motion

Energy

Energy and the Future

Matter and Heat

Electricity and Magnetism

Waves

The Nucleus

The Atom

The Periodic Law

Crystals, Ions, and Solutions

Organic Chemistry

Atmosphere and Hydrosphere

The Rock Cycle

The Evolving Earth

The Solar System

The Stars

The Universe Galaxies

Filters

The number of moles of atomic oxygen in 2 moles of Ca₃PO₄)₂ is

The number of moles of H₂O formed when 1 mole of O₂ reacts with C₅H₁₂ in the reaction C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O is

The atomic mass of N is 14 u and that of Ca is 40 u. The proportion of N by mass in the compound Ca₃N₂ is

Sulfur has an atomic mass of 32 u and Avogadro's number is 6 × 10²³ formula units/mole. The number of sulfur atoms in 1 g of sulfur is