MCQs — Energetics

Practice questions for Chemistry.

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Question 1

The study of energy changes in chemical reactions is called:

A. Thermodynamics only

B. Chemical energetics

C. Stoichiometry

D. Electrochemistry

Question 2

Energy in the form of heat is developed or absorbed during a chemical reaction mainly because:

A. Atoms change their mass during the reaction

B. Old bonds are broken and new bonds are formed

C. Reactions always occur at constant temperature

D. Electrons never move during a reaction

Question 3

Breaking a chemical bond always:

A. Releases energy

B. Consumes (requires) energy

C. Has no effect on energy

D. Converts mass into energy

Question 4

Forming a chemical bond always:

A. Consumes (requires) energy

B. Releases energy

C. Has no effect on energy

D. Destroys mass

Question 5

If the energy released in forming new bonds is greater than the energy expended in breaking old bonds, the overall result is:

A. A net absorption of energy (an endothermic process)

B. A net release of chemical energy (an exothermic process)

C. No net energy change at all

D. A change in the number of atoms present

Question 6

If the energy expended in breaking old bonds is greater than the energy released in forming new bonds, the overall result is:

A. A net release of chemical energy (an exothermic process)

B. A net absorption of energy (an endothermic process)

C. No net energy change at all

D. A change in the identity of the elements involved

Question 7

In chemistry, the part of the universe that we focus our attention on is called the:

A. Surroundings

B. Environment

C. System

D. Universe

Question 8

The rest of the universe, outside of what we are focusing on, is called the:

A. System

B. Surroundings (environment)

C. Reactant

D. Product

Question 9

In chemistry, a system is usually best described as:

A. A fixed, unchanging container

B. A substance that changes physically or chemically

C. Any object with no chemical properties

D. A synonym for the entire universe

Question 10

When studying the reaction between limestone and hydrochloric acid solution in a test tube, which of the following forms the system?

A. The test tube itself, and nothing else

B. The limestone and the hydrochloric acid solution

C. The room the test tube is sitting in

D. The laboratory bench

Question 11

In the limestone/hydrochloric acid example, the test tube itself and everything around it would be considered:

A. Part of the system

B. The surroundings (environment)

C. Irrelevant and not classified at all

D. A separate, second system

Question 12

When studying the thermal decomposition of a compound, the sample of the compound itself represents the:

A. Surroundings

B. System

C. Catalyst

D. Product only

Question 13

In the thermal-decomposition example, the beaker, the heat source, and everything else nearby would be considered:

A. Part of the system

B. The surroundings (environment)

C. The reactants only

D. Irrelevant and not classified at all

Question 14

During a chemical reaction, energy is generally described as being:

A. Created from nothing within the system

B. Exchanged between the system and its surroundings

C. Permanently trapped within the system, with no exchange

D. Unrelated to the system/surroundings distinction

Question 15

A chemical reaction that proceeds with the evolution or absorption of heat is called a:

A. Redox reaction

B. Thermochemical reaction

C. Neutralization reaction

D. Precipitation reaction

Question 16

A balanced chemical equation that also shows the heat change of a reaction is called a:

A. Word equation

B. Thermochemical equation

C. Ionic equation

D. Skeleton equation

Question 17

The branch of chemistry that deals with heat or thermal energy changes in chemical reactions is called:

A. Stoichiometry

B. Thermochemistry

C. Electrochemistry

D. Organic chemistry

Question 18

A chemical reaction that proceeds with the evolution of heat is called a(n):

A. Endothermic reaction

B. Exothermic reaction

C. Reversible reaction

D. Catalytic reaction

Question 19

In an exothermic reaction, the chemical system:

A. Absorbs energy from the surroundings as reactants convert to products

B. Transfers energy to the surroundings as reactants convert to products

C. Undergoes no energy exchange at all

D. Only exchanges energy after the reaction is complete

Question 20

Burning of fuels is described as a highly:

A. Endothermic reaction

B. Exothermic reaction

C. Neutral reaction with no energy change

D. Non-chemical process

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