Question 1

Which law states that energy is neither created nor destroyed in a chemical reaction, but is converted between kinetic and potential forms?

Accepted Answer

Law of conservation of energy

Question 2

A reaction in which $$\Delta H \u003c 0$$ and heat is released to the surroundings is classified as:

Accepted Answer

Exothermic

Question 3

Which of the following best describes the change in entropy ($$\Delta S) $$when a solid melts to form a liquid?

Accepted Answer

$$\Delta S \u003e 0$$; entropy increases

Question 4

Given the reaction: $$\mathrm{NH_4NO_3(s) \rightarrow NH_4NO_3(aq)}$$, which statement is correct?

Accepted Answer

Heat is absorbed from the surroundings; $$\Delta H \u003e 0$$

Question 5

Which equation correctly relates Gibbs free energy ($$\Delta G$$), enthalpy ($$\Delta H$$), and entropy ($$\Delta S) at $$temperature $$T$$?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 6

A reaction is spontaneous if:

Accepted Answer

$$\Delta G \u003c 0$$

Question 7

Which of the following is true for an endergonic reaction?

Accepted Answer

$$\Delta G \u003e 0$$; reaction is nonspontaneous

Question 8

Consider the combustion of sucrose: $$\mathrm{C$$_{12}$$H_{22}O$$_{11} + 12O_2 \rightarrow 12CO_2 + 11H_2O}$, which statement is correct?

Accepted Answer

The reaction releases heat and is exothermic

Question 9

Which of the following changes will result in the greatest increase in entropy ($$\Delta S$$)?

Accepted Answer

Liquid $$\rightarrow$$ gas

Question 10

If a reaction has $$\Delta H  0$$, what can be said about $$\Delta G at $$all temperatures?

Accepted Answer

$$\Delta G$$ will always be negative

Question 11

Which of the following best describes the role of ATP in cellular processes?

Accepted Answer

ATP is hydrolyzed to ADP and energy, which is used to move ions across membranes

Question 12

Which of the following energy diagrams represents an exergonic reaction?

Accepted Answer

The reactants have higher energy than the products

Question 13

A food contains 2 g of carbohydrates, 10 g of fat, and 12 g of protein. What is the total energy content in Calories?

Accepted Answer

150 Cal

Question 14

Which of the following statements about exothermic reactions is correct?

Accepted Answer

They release heat to the surroundings

Question 15

For a reaction to be spontaneous at all temperatures, which combination of $$\Delta H$$ and $$\Delta S is $$required?

Accepted Answer

$$\Delta H  0$$

Question 16

Which of the following is true for an endothermic reaction?

Accepted Answer

Heat is absorbed from the surroundings

Question 17

If $$\Delta G \u003e 0$$ for a reaction, which statement is correct?

Accepted Answer

The reaction is nonspontaneous

Question 18

Which of the following is a correct statement about the energy content of food?

Accepted Answer

1 g of fat provides more energy than 1 g of protein

Question 19

Which of the following processes is associated with an increase in entropy?

Accepted Answer

Melting of a solid to a liquid

Question 20

Which of the following is true for an exergonic reaction?

Accepted Answer

It is spontaneous and releases free energy

Thermodynamics and Energy in Chemical Reactions

Study Guide - Practice Questions