Chemical Reactions: Types, Balancing, Stoichiometry, and Rates

Question 1

An equilibrium constant of 0.5 indicates that a chemical reaction will:

Accepted Answer

Favor the formation of reactants

Answer

Reach completion

Answer

Favor the formation of products

Answer

Have a very slow reaction rate

Question 2

Which factor does **not** affect the rate of a chemical reaction?

Accepted Answer

Volume of the reaction vessel

Answer

Concentration of reactants

Answer

Temperature

Answer

Presence of a catalyst

Question 3

What is the enthalpy change (ΔH) for an exothermic reaction?

Accepted Answer

Negative

Answer

Positive

Answer

Zero

Answer

Variable

Question 4

Which type of reaction is typically accompanied by the release of heat?

Accepted Answer

Exothermic

Answer

Endothermic

Answer

Redox

Answer

Neutralization

Question 5

Which of the following is a redox reaction?

Accepted Answer

CH₄ + 2O₂ -> CO₂ + 2H₂O

Answer

2Na + Cl₂ -> 2NaCl

Answer

CaCO₃ -> CaO + CO₂

Answer

HCl + NaOH -> NaCl + H₂O

Question 6

What is the pH of a solution with a [H⁺] concentration of 10⁻⁷ M?

Accepted Answer

7

Answer

0

Answer

14

Answer

Not determinable from the given information

Question 7

Which of the following is a weak acid?

Accepted Answer

Acetic acid

Answer

Hydrochloric acid

Answer

Sulfuric acid

Answer

Nitric acid

Question 8

How do catalysts influence the speed of chemical reactions?

Accepted Answer

Catalysts accelerate reactions by reducing the activation energy.

Answer

Catalysts slow down reactions by increasing the activation energy.

Answer

Catalysts do not affect the speed of reactions.

Answer

Catalysts can only be used to speed up reactions that release heat.

Question 9

Which real-world application depends mainly on the burning of fossil fuels?

Accepted Answer

Driving cars

Answer

Digesting food

Answer

Growing plants

Answer

Mixing acids and bases

Question 10

Which statement accurately describes the limiting reactant in a chemical reaction?

Accepted Answer

The reactant that is completely consumed, determining the maximum amount of product formed.

Answer

The reactant present in excess, allowing for the complete consumption of other reactants.

Answer

The reactant that appears on the left side of a balanced chemical equation.

Answer

The reactant with the highest molar mass among all reactants.

Question 11

In a balanced chemical equation, the coefficients represent:

Accepted Answer

The relative proportions of reactants and products

Answer

The number of atoms of each element involved in the reaction

Answer

The mass of each reactant and product

Answer

The reaction rate

Question 12

Which of the following is a strong acid that completely dissociates in water?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Answer

Water

Question 13

What is the pH of a solution with a hydrogen ion concentration of 1 x 10⁻⁷ M?

Accepted Answer

7

Answer

0

Answer

10

Answer

14

Question 14

Which of the following reactions is an oxidation-reduction reaction, involving a change in oxidation states of the reactants?

Accepted Answer

Combustion

Answer

Neutralization

Answer

Precipitation

Answer

Double displacement

Question 15

In the reaction: Fe + 2HCl → FeCl₂ + H₂, which species acts as the oxidizing agent, causing the oxidation of another species?

Accepted Answer

HCl

Answer

Fe

Answer

FeCl₂

Answer

H₂

Question 16

Which of the following substances can act as a catalyst, increasing the reaction rate of a chemical reaction without being consumed?

Accepted Answer

Manganese dioxide

Answer

Sodium chloride

Answer

Hydrochloric acid

Answer

Water

Question 17

Activation energy, denoted by Ea, is the minimum amount of _____ required for a chemical reaction to occur.

Accepted Answer

Energy

Answer

Heat

Answer

Mass

Answer

Volume

Question 18

Which of the following factors does NOT affect the rate of a homogeneous chemical reaction?

Accepted Answer

Surface area of reactants

Answer

Concentration of reactants

Answer

Temperature

Answer

Nature of the reactants

Question 19

In the compound NaCl, what is the ratio of sodium atoms to chlorine atoms?

Accepted Answer

1:1

Answer

2:3

Answer

2:1

Answer

1:2

Question 20

Which type of chemical reaction involves a transfer of electrons?

Accepted Answer

Redox reaction

Answer

Acid-base reaction

Answer

Precipitation reaction

Answer

Combustion reaction

Question 21

Which of the following is an example of a chemical reaction that produces a gas?

Accepted Answer

Reaction between sodium hydrogen carbonate and acetic acid

Answer

Redox reaction

Answer

Neutralization reaction

Answer

Precipitation reaction

Question 22

What is the primary purpose of using a Bunsen burner in chemical reactions?

Accepted Answer

To provide and control heat

Answer

To measure temperature

Answer

To initiate reactions

Answer

To mix reactants

Question 23

Which feature characterizes a chemical reaction that has reached equilibrium?

Accepted Answer

The forward and reverse reactions are occurring at equal rates

Answer

The concentration of products is greater than the concentration of reactants

Answer

The reaction is complete

Question 24

Which physical or chemical change does NOT release energy in the form of heat?

Accepted Answer

Melting

Answer

Neutralization

Answer

Explosion

Answer

Combustion

Question 25

Which of the following factors has the greatest effect on the rate of a chemical reaction?

Accepted Answer

Temperature

Answer

Presence of a catalyst

Answer

Surface area of reactants

Answer

Concentration of reactants

Question 26

Identify the type of chemical reaction in which a metal replaces a less reactive metal in a compound:

Accepted Answer

Displacement reaction

Answer

Neutralization reaction

Answer

Combustion reaction

Answer

Precipitation reaction

Question 27

Which of the following is a characteristic of an endothermic reaction?

Accepted Answer

Absorbs heat

Answer

Increases temperature

Answer

Releases heat

Answer

Decreases temperature

Question 28

Identify the limiting reactant in the following reaction: 4NH₃ + 5O₂ → 4NO + 6H₂O

Accepted Answer

NH₃

Answer

NO

Answer

Cannot be determined

Answer

O₂

Question 29

Which of the following is a heterogeneous catalyst in the catalytic converter of a car?

Accepted Answer

Platinum

Answer

Ammonia

Answer

Nitrogen

Answer

Hydrogen

Question 30

Identify the product of the following neutralization reaction: HCl + NaOH →

Accepted Answer

NaCl + H₂O

Answer

Na + H₂O

Answer

Cl₂ + H₂O

Question 31

Which of the following types of chemical reactions involves the combination of two or more substances to form a single, more complex substance?

Accepted Answer

Synthesis reaction

Answer

Double-displacement reaction

Answer

Decomposition reaction

Answer

Single-displacement reaction

Question 32

Balance the following chemical equation: Fe + HCl → FeCl₂ + H₂

Accepted Answer

Fe + 2HCl → FeCl₂ + H₂

Answer

2Fe + 2HCl → Fe₂Cl₄ + 2H₂

Answer

2Fe + HCl → 2FeCl + H₂

Answer

Fe + HCl → FeCl₃ + H₂

Question 33

Which factor has a significant influence on the rate of a chemical reaction?

Accepted Answer

Temperature

Answer

Volume of the reactants

Answer

Shape of the reaction vessel

Answer

Color of the reactants

Question 34

Which statement accurately describes the role of a catalyst in a chemical reaction?

Accepted Answer

A substance that increases the reaction rate without being consumed

Answer

A substance that decreases the reaction rate

Answer

A substance that is formed as a product of the reaction

Question 35

Which substance among the following is classified as a strong electrolyte?

Accepted Answer

Sodium chloride (NaCl)

Answer

Carbon dioxide (CO₂)

Answer

Acetic acid (CH₃COOH)

Answer

Sucrose (C₁₂H₂₂O₁₁)

Question 36

Which of the following is a correctly balanced chemical equation?

Accepted Answer

C3H8 + 5O2 -> 3CO2 + 4H2O

Answer

O2 + 2H2 -> H2O

Answer

H2O -> H2 + O

Answer

2H2 + O2 -> H4O2

Question 37

What type of chemical reaction occurs when two or more substances combine to form a single product?

Accepted Answer

Combination

Answer

Decomposition

Answer

Single Displacement

Question 38

Which of the following does NOT affect the rate of a chemical reaction?

Accepted Answer

Inert gases

Answer

Concentration

Answer

Temperature

Answer

Surface area

Question 39

What is the product of the following reaction: CH4 + 2O2 -> ?

Accepted Answer

CO2 + 2H2O

Answer

C + 2H2O

Answer

CH3OH + H2O

Question 40

Which of the following is a characteristic of exothermic reactions?

Accepted Answer

Release heat

Answer

Occur spontaneously

Answer

Produce no light or sound

Answer

Absorb heat

Question 41

What is the primary purpose of using a catalyst in a chemical reaction?

Accepted Answer

To increase the reaction rate

Answer

To change the products of the reaction

Answer

To decrease the reaction rate

Answer

To prevent the reaction from occurring

Question 42

Which of the following reactions is an acid-base reaction?

Accepted Answer

HCl + NaOH -> NaCl + H2O

Answer

CH4 + 2O2 -> CO2 + 2H2O

Answer

2Na + 2H2O -> 2NaOH + H2

Answer

Fe + CuSO4 -> FeSO4 + Cu

Question 43

What is the molar mass of glucose (C6H12O6)?

Accepted Answer

180.16 g/mol

Answer

108.11 g/mol

Answer

72.06 g/mol

Answer

120.12 g/mol

Question 44

Which of the following is a redox reaction?

Accepted Answer

2Fe + 3Cl2 -> 2FeCl3

Answer

CH4 + 2O2 -> CO2 + 2H2O

Answer

NaOH + HCl -> NaCl + H2O

Answer

CaCO3 -> CaO + CO2