Question 1

Which of the following best describes an exergonic reaction, as illustrated in the provided diagrams?

Accepted Answer

A reaction where the free energy of the products is lower than the reactants, releasing energy.

Question 2

Given the equation $$\Delta G = \Delta H - T\Delta S$$, which combination of $$\Delta H$$ and $$\Delta S$$ will always result in a spontaneous reaction at any temperature?

Accepted Answer

$$\Delta H  0$$

Question 3

A canoe travels downstream without rowing, as shown in the first image. Which thermodynamic concept does this best illustrate?

Accepted Answer

Exergonic reaction ($$\Delta G \u003c 0)$$

Question 4

Which statement about catalysts is correct based on the reaction coordinate diagram?

Accepted Answer

Catalysts lower the activation energy, making reactions proceed faster.

Question 5

If a reaction has $$\Delta H \u003e 0$$ and $$\Delta S \u003e 0$$, under what conditions will it be spontaneous?

Accepted Answer

Only at temperatures above $$T = \Delta H / \Delta S$$

Question 6

Which macronutrient provides the most energy per gram according to the nutrition label calculation?

Accepted Answer

Fats

Question 7

What is the role of ATP in cellular reactions, as shown in the chemical example diagram?

Accepted Answer

ATP couples with endergonic reactions to make them overall exergonic.

Question 8

Which factor does NOT increase the rate of a chemical reaction, based on the collision diagrams?

Accepted Answer

Decreasing the amount of reactants

Question 9

Enzymes are highly specific biological catalysts. What is the consequence of a defective enzyme, such as lactase?

Accepted Answer

The substrate is not properly broken down, leading to disease symptoms.

Question 10

A reaction is enthalpically favored ($$\Delta H \u003c 0) $$but entropically opposed ($$\Delta S \u003c 0). $$When will this reaction be spontaneous?

Accepted Answer

Only at temperatures below $$T = \Delta H / \Delta S$$

Question 11

Which of the following best describes the effect of increasing temperature on reaction rate?

Accepted Answer

It increases the kinetic energy, causing more frequent and energetic collisions.

Question 12

Which scenario best represents an endergonic reaction?

Accepted Answer

A canoe traveling upstream, requiring energy input

Question 13

What is the main function of the active site of an enzyme?

Accepted Answer

It immobilizes and orients reactants to facilitate the reaction.

Question 14

Which of the following is true about the spontaneity of a reaction at equilibrium ($$\Delta G = 0$$)?

Accepted Answer

There is no net reaction; the system is stable.

Question 15

Which disease is caused by a deficiency in the enzyme lactase?

Accepted Answer

Lactose intolerance

Question 16

If a reaction is both enthalpically and entropically opposed ($$\Delta H \u003e 0$$, $$\Delta S \u003c 0$$), what is the value of $$\Delta G$$ and its spontaneity?

Accepted Answer

$$\Delta G \u003e 0$$, nonspontaneous at all temperatures

Question 17

Which of the following is NOT a function of a catalyst?

Accepted Answer

Being consumed in the reaction

Question 18

Which of the following statements about entropy ($$\Delta S) is $$correct?

Accepted Answer

A positive $$\Delta S$$ means increased disorder, which is thermodynamically favorable.

Question 19

Which of the following best explains why artificial sweeteners provide fewer Calories than sugar?

Accepted Answer

They contain less potential energy in their chemical bonds.

Chapter 5: Chemical Reactions – Thermodynamics and Kinetics

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