Question 1

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. A

Question 2

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. 
A) a lighted candle. 
B) the rusting of iron. 
C) the lighting of a match. 
D) a log burning in a fireplace. B

Question 3

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

Question 4

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

Question 5

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

Question 6

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 7

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 8

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

Accepted Answer

A) CO2. 
B) SiO2. 
C) BaSO4. 
D) H2O. 
A) CO2. 
B) SiO2. 
C) BaSO4. 
D) H2O.

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

Question 10

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. 
A) gasoline additive that reduces pollution. 
B) constituent of natural gas. 
C) solvent used in electrolysis. 
D) biological catalyst.

Question 11

A storage battery stores

Accepted Answer

A) electrons. 
B) electric current. 
C) energy. 
D) voltage. 
A) electrons. 
B) electric current. 
C) energy. 
D) voltage.

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

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

Question 14

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. 
A) 5. 
B) 10. 
C) 25. 
D) 50.

Question 15

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. 
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.

Question 16

According to Aristotle, every flammable material consisted of

Accepted Answer

A) earth and fire. 
B) phlogiston. 
C) oxygen and earth. 
D) air and heat. 
A) earth and fire. 
B) phlogiston. 
C) oxygen and earth. 
D) air and heat.

Question 17

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

Accepted Answer

A) electrons. 
B) H+ ions. 
C) O2- ions. 
D) O2 molecules. 
A) electrons. 
B) H+ ions. 
C) O2- ions. 
D) O2 molecules.

Question 18

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

Question 19

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

Question 20

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

The proportion of oxygen in dry air is about

An example of slow oxidation is

An oxide decomposed by heating will give

The speed of a chemical reaction is not affected by

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

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

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

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

The decomposition of an unstable compound usually

An enzyme is a

A storage battery stores

The number of formula units in a mole of a substance

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

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

Which of the following statements about ozone is incorrect?

According to Aristotle, every flammable material consisted of

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

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

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

The Scientific Method

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Exam 12: Chemical Reactions

The proportion of oxygen in dry air is about

An example of slow oxidation is

An oxide decomposed by heating will give

The speed of a chemical reaction is not affected by

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

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

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

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

The decomposition of an unstable compound usually

An enzyme is a

A storage battery stores

The number of formula units in a mole of a substance

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

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

Which of the following statements about ozone is incorrect?

According to Aristotle, every flammable material consisted of

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

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

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

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

Filters

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

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

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

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

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

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