Question 1

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.E) A) and B)
F) B) and D)

Question 2

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 mole of sulfur is

Accepted Answer

A)  32.
B)  1.9 * 1022.
C)  6 * 1023.
D)  1.9 * 1025.E) None of the above
F) A) and B)

Question 3

The proportion of oxygen in dry air is about

Accepted Answer

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

Question 4

An enzyme is a

Accepted Answer

A)  gasoline additive that reduces pollution.
B)  constituent of natural gas.
C)  solvent used in electrolysis.
D)  biological catalyst.E) All of the above
F) B) and C)

Question 5

A storage battery stores

Accepted Answer

A)  electrons.
B)  electric current.
C)  energy.
D)  voltage.E) B) and D)
F) C) and D)

Question 6

Silicon has an atomic mass of 28 u and Avogadro's number is 6 * 1023 formula units/mole.The mass of Avogadro's number of silicon atoms is

Accepted Answer

A)  1 g.
B)  28 g.
C)  6 * 1023 g.
D)  1.68 * 1025 g.E) C) and D)
F) All of the above

Question 7

Which of the following compounds is not classed as an oxide?

Accepted Answer

A)  CO2.
B)  SiO2.
C)  BaSO4.
D)  H2O.E) B) and D)
F) A) and B)

Question 8

An oxide decomposed by heating will give

Accepted Answer

A)  oxygen and another element.
B)  CO2 and water.
C)  oxygen ions and metal ions.
D)  a metal and water.E) A) and D)
F) B) and C) A

Question 9

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.E) None of the above
F) B) and C)

Question 10

The number of moles of O2 needed to react with 10 moles of C2H2 in the reaction 2C2H2 + 5O2  →\rarr→  4CO2 + 2H2O is

Accepted Answer

A)  5.
B)  10.
C)  25.
D)  50. E) A) and B)
F) A) and C)

Question 11

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.E) A) and B)
F) A) and C)

Question 12

Which of the following statements about ozone is incorrect?

Accepted Answer

A)  The formula of ozone is O3.
B)  Ozone molecules are more stable than those of ordinary oxygen.
C)  At low altitudes ozone contributes to smog.
D)  At high altitudes ozone absorbs solar ultraviolet radiation.E) B) and D)
F) None of the above

Question 13

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

Accepted Answer

A)  3/4.
B)  4/3.
C)  6.
D)  8. E) A) and D)
F) B) and C)

Question 14

The speed of a chemical reaction is not affected by

Accepted Answer

A)  the surface area of the reactants.
B)  catalysts.
C)  the concentration of reactants.
D)  the type of bond in reaction products.E) A) and B)
F) A) and C)

Question 15

Silicon has an atomic mass of 28 u and Avogadro's number is 6 * 1023 formula units/mole.The mass of 1 mole of silicon is

Accepted Answer

A)  1 g.
B)  28 g.
C)  6 * 1023 g.
D)  1.68 * 1025 g.E) A) and C)
F) C) and D)

Question 16

Oxidation-reduction reactions involve the transfer between the reacting substances of

Accepted Answer

A)  electrons.
B)  H+ ions.
C)  O2- ions.
D)  O2 molecules.E) C) and D)
F) None of the above

Question 17

An example of slow oxidation is

Accepted Answer

A)  a lighted candle.
B)  the rusting of iron.
C)  the lighting of a match.
D)  a log burning in a fireplace.E) A) and C)
F) All of the above B

Question 18

According to Aristotle, every flammable material consisted of

Accepted Answer

A)  earth and fire.
B)  phlogiston.
C)  oxygen and earth.
D)  air and heat.E) A) and B)
F) All of the above

Question 19

The number of moles of atomic oxygen in 2 moles of Ca3(PO4) 2 is

Accepted Answer

A)  2.
B)  4.
C)  8.
D)  16.E) A) and B)
F) All of the above

Question 20

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.E) A) and B)
F) B) and D)

Exam 12: Chemical Reactions

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

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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 mole of sulfur is

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The proportion of oxygen in dry air is about

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An enzyme is a

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A storage battery stores

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Silicon has an atomic mass of 28 u and Avogadro's number is 6 * 1023 formula units/mole.The mass of Avogadro's number of silicon atoms is

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Which of the following compounds is not classed as an oxide?

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An oxide decomposed by heating will give

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The decomposition of an unstable compound usually

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The number of moles of O2 needed to react with 10 moles of C2H2 in the reaction 2C2H2 + 5O2 →\rarr→ 4CO2 + 2H2O is

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

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Which of the following statements about ozone is incorrect?

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

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The speed of a chemical reaction is not affected by

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Silicon has an atomic mass of 28 u and Avogadro's number is 6 * 1023 formula units/mole.The mass of 1 mole of silicon is

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Oxidation-reduction reactions involve the transfer between the reacting substances of

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An example of slow oxidation is

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According to Aristotle, every flammable material consisted of

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The number of moles of atomic oxygen in 2 moles of Ca3(PO4) 2 is

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The number of formula units in a mole of a substance

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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

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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 mole of sulfur is

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A

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Silicon has an atomic mass of 28 u and Avogadro's number is 6 * 10²³ formula units/mole.The mass of Avogadro's number of silicon atoms is

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A

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The number of moles of O₂ needed to react with 10 moles of C₂H₂ in the reaction 2C₂H₂ + 5O₂ $\rarr$ 4CO₂ + 2H₂O is

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

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Silicon has an atomic mass of 28 u and Avogadro's number is 6 * 10²³ formula units/mole.The mass of 1 mole of silicon is

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B

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The number of moles of atomic oxygen in 2 moles of Ca₃(PO₄) ₂ is

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