Question 1

Which of the following best describes the difference between kinetic energy and potential energy?

Accepted Answer

Kinetic energy is the energy of motion, while potential energy is due to position or composition.

Question 2

A propane barbecue is used to grill vegetables. Which of the following best describes the chemical system and its surroundings in this scenario?

Accepted Answer

The chemical system is the propane gas and oxygen; the surroundings are the barbecue and the food.

Question 3

Which of the following equations correctly represents an exothermic chemical reaction?

Accepted Answer

$$\mathrm{CH_4$(g) + 2O_2(g) \rightarrow CO_2$(g) + 2H_2O(g) + energy}$$

Question 4

Which of the following statements about the law of conservation of energy is correct?

Accepted Answer

Energy cannot be created or destroyed, only converted from one form to another.

Question 5

A glow stick is an example of which type of system?

Accepted Answer

Closed system

Question 6

Which process is endothermic?

Accepted Answer

Melting of ice

Question 7

Why does an iceberg at 0°C contain more thermal energy than a cup of boiling water at 100°C?

Accepted Answer

Because the iceberg contains more water molecules, so the total thermal energy is greater.

Question 8

Which of the following best describes what happens during a nuclear fission reaction?

Accepted Answer

A heavy nucleus splits into two lighter nuclei, releasing energy.

Question 9

Which of the following is true about all nuclear reactions compared to chemical reactions?

Accepted Answer

Nuclear reactions release much more energy per unit mass than chemical reactions.

Question 10

Which equation represents the fusion reaction that occurs in the Sun?

Accepted Answer

$$\mathrm{2_1H + 3_1H \rightarrow 4_2He + 1_0n}$$

Question 11

Which of the following best describes heat?

Accepted Answer

The transfer of thermal energy from a warmer object to a cooler object.

Question 12

During the combustion of methane, which of the following statements is true?

Accepted Answer

Energy is released to the surroundings, and the products have lower potential energy.

Question 13

Which of the following is an example of an open system?

Accepted Answer

A boiling solution in an unsealed beaker

Question 14

Which of the following best explains why bond breaking requires energy?

Accepted Answer

Because the potential energy of the separated atoms is higher than when bonded.

Question 15

Which of the following is true for an endothermic reaction?

Accepted Answer

The products have higher potential energy than the reactants.

Question 16

A uranium-235 nucleus undergoes fission after absorbing a neutron. Which of the following is a correct representation of this reaction?

Accepted Answer

$$\mathrm{1_0n + 235_{92}U \rightarrow 92_{36}Kr + 141_{56}Ba + 3\ 1_0n}$$

Question 17

Which of the following best describes temperature?

Accepted Answer

A measure of the average kinetic energy of the entities in a substance.

Question 18

Which of the following is NOT a correct statement about energy changes in chemical and nuclear reactions?

Accepted Answer

Energy can be created during a chemical reaction.

Question 19

Which of the following best explains why the temperature of the surroundings increases during an exothermic reaction?

Accepted Answer

Because energy is released from the system to the surroundings.

Question 20

Which of the following is an example of a process where energy is absorbed from the surroundings?

Accepted Answer

Synthesis of nitric oxide from nitrogen and oxygen

Lesson 5.1: Energy Changes in Chemical and Nuclear Reactions: Thermochemistry Study Guide

Study Guide - Practice Questions