Question 1

The number of moles of atomic oxygen in 1 mole of Ca3(PO4)2 is

Accepted Answer

A) 1. 
B) 2. 
C) 4. 
D) 8. 
A) 1. 
B) 2. 
C) 4. 
D) 8. D

Question 2

The number of calcium atoms in 1 mole of calcium is

Accepted Answer

A) 40. 
B) 1.5 * 1022. 
C) 3 * 1022. 
D) 6 * 1023. 
A) 40. 
B) 1.5 * 1022. 
C) 3 * 1022. 
D) 6 * 1023. D

Question 3

When a substance gains 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. A

Question 4

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 5

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 6

The energy liberated in a chemical reaction comes from the

Accepted Answer

A) kinetic energy of atomic electrons. 
B) potential energy of atomic electrons. 
C) activation energy of atomic electrons. 
D) equilibrium energy of atomic electrons. 
A) kinetic energy of atomic electrons. 
B) potential energy of atomic electrons. 
C) activation energy of atomic electrons. 
D) equilibrium energy of atomic electrons.

Question 7

An example of an exothermic process is the

Accepted Answer

A) dissociation of a salt in water solution. 
B) neutralization of an acid by a base. 
C) electrolysis of water. 
D) melting of ice. 
A) dissociation of a salt in water solution. 
B) neutralization of an acid by a base. 
C) electrolysis of water. 
D) melting of ice.

Question 8

The mass of 1 mole of oxygen, O2, is 32 g.The atomic mass of oxygen is

Accepted Answer

A) 16 u. 
B) 16 g. 
C) 32 u. 
D) 32 g. 
A) 16 u. 
B) 16 g. 
C) 32 u. 
D) 32 g.

Question 9

Approximately 4/5 of dry air consists of

Accepted Answer

A) oxygen. 
B) nitrogen. 
C) carbon dioxide. 
D) argon. 
A) oxygen. 
B) nitrogen. 
C) carbon dioxide. 
D) argon.

Question 10

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.

Question 11

A chemical equilibrium occurs when the

Accepted Answer

A) mass of the products equals the mass of the reactants. 
B) number of molecules of the products equals the number of molecules of the reactants. 
C) concentration of the products equals the concentration of the reactants. 
D) speed of the forward reaction equals the speed of the reverse reaction. 
A) mass of the products equals the mass of the reactants. 
B) number of molecules of the products equals the number of molecules of the reactants. 
C) concentration of the products equals the concentration of the reactants. 
D) speed of the forward reaction equals the speed of the reverse reaction.

Question 12

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 13

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 14

The scientist whose experiments showed that tin, upon heating, combined with a gas from the air was

Accepted Answer

A) Priestley. 
B) Stahl. 
C) Lavoisier. 
D) Becher. 
A) Priestley. 
B) Stahl. 
C) Lavoisier. 
D) Becher.

Question 15

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 16

Chemical reactions that give off energy are called

Accepted Answer

A) endothermic. 
B) exothermic. 
C) activated. 
D) oxidation-reduction. 
A) endothermic. 
B) exothermic. 
C) activated. 
D) oxidation-reduction.

Question 17

The number of moles of O2 needed to react with 10 moles of C2H2 in the reaction 2C2 H2 + 5O2 $\rarr$ 4CO2 + 2 H2O is

Accepted Answer

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

Question 18

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 19

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.

Question 20

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.

The number of moles of atomic oxygen in 1 mole of Ca₃(PO₄)₂ is

The number of calcium atoms in 1 mole of calcium is

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

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

According to Aristotle, every flammable material consisted of

The energy liberated in a chemical reaction comes from the

An example of an exothermic process is the

The mass of 1 mole of oxygen, O₂, is 32 g.The atomic mass of oxygen is

Approximately 4/5 of dry air consists of

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

A chemical equilibrium occurs when the

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

An enzyme is a

The scientist whose experiments showed that tin, upon heating, combined with a gas from the air was

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

Chemical reactions that give off energy are called

The number of moles of O₂ needed to react with 10 moles of C₂H₂ in the reaction 2C₂ H₂ + 5O₂ $\rarr$ 4CO₂ + 2 H₂O is

The speed of a chemical reaction is not affected by

An oxide decomposed by heating will give

Which of the following statements about ozone is incorrect?

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

Universe

Filters

Exam 12: Chemical Reactions

The number of moles of atomic oxygen in 1 mole of Ca3(PO4)2 is

The number of calcium atoms in 1 mole of calcium is

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

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

According to Aristotle, every flammable material consisted of

The energy liberated in a chemical reaction comes from the

An example of an exothermic process is the

The mass of 1 mole of oxygen, O2, is 32 g.The atomic mass of oxygen is

Approximately 4/5 of dry air consists of

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

A chemical equilibrium occurs when the

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

An enzyme is a

The scientist whose experiments showed that tin, upon heating, combined with a gas from the air was

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

Chemical reactions that give off energy are called

The number of moles of O2 needed to react with 10 moles of C2H2 in the reaction 2C2 H2 + 5O2 →\rarr→ 4CO2 + 2 H2O is

The speed of a chemical reaction is not affected by

An oxide decomposed by heating will give

Which of the following statements about ozone is incorrect?

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

Universe

Filters

The number of moles of atomic oxygen in 1 mole of Ca₃(PO₄)₂ 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 mass of 1 mole of oxygen, O₂, is 32 g.The atomic mass of oxygen 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 number of moles of O₂ needed to react with 10 moles of C₂H₂ in the reaction 2C₂ H₂ + 5O₂ $\rarr$ 4CO₂ + 2 H₂O is