Question 1

Which of the following statements best describes the difference between thermodynamics and kinetics in chemical reactions?

Accepted Answer

Thermodynamics describes the energy changes in a reaction, while kinetics describes how fast the reaction occurs.

Question 2

A reaction has $$\Delta H = -150\ \mathrm{kJ}$$ and $$\Delta S = -200\ \mathrm{J/K} at$$ $$T = 298\ \mathrm{K}. $$What is the value of $$\Delta G$$ for this reaction, and is it spontaneous at this temperature?

Accepted Answer

$$\Delta G = -90.4\ \mathrm{kJ}$$; the reaction is spontaneous.

Question 3

Which of the following changes will increase the rate of a chemical reaction?

Accepted Answer

Adding a catalyst.

Question 4

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction with $$\Delta G \u003c 0$$ that is spontaneous.

Question 5

Which of the following statements about ATP hydrolysis is correct?

Accepted Answer

ATP hydrolysis is exergonic and releases energy that can drive other reactions.

Question 6

A patient with lactose intolerance is unable to digest lactose because they lack which enzyme?

Accepted Answer

Lactase

Question 7

Which of the following best describes the role of NAD$$^+ in $$cellular redox reactions?

Accepted Answer

NAD$$^+$$ acts as an oxidizing agent, accepting electrons from other molecules.

Question 8

Which of the following statements about the combustion of alkanes is correct?

Accepted Answer

Combustion of alkanes requires O$$_2$$ and produces CO$$_2$$, H$$_2O$$, and heat.

Question 9

Which of the following best describes a hydrolysis reaction?

Accepted Answer

A reaction in which water breaks another molecule into two smaller molecules.

Question 10

Which of the following is true about the spontaneity of a reaction with $$\Delta H \u003e 0$$ and $$\Delta S \u003e 0$$?

Accepted Answer

The reaction is spontaneous only at high temperatures.

Question 11

Which of the following best explains why fats provide more than twice as many Calories per gram as carbohydrates?

Accepted Answer

Fats have more C-H bonds and are more reduced, allowing for more energy release upon oxidation.

Question 12

Which of the following is a correct statement about the activation energy of a reaction?

Accepted Answer

A catalyst lowers the activation energy, increasing the reaction rate.

Question 13

Which of the following is an example of a condensation reaction?

Accepted Answer

Formation of an ester from a carboxylic acid and an alcohol, releasing water

Question 14

In the hydrogenation of an alkene to form an alkane, which of the following is required?

Accepted Answer

A catalyst, such as platinum or palladium

Question 15

Which of the following best describes the change in oxidation state when an organic compound is oxidized?

Accepted Answer

It loses C-H bonds and/or gains C-O bonds.

Question 16

Which of the following reactions is most likely to be irreversible?

Accepted Answer

A reaction with a large negative $$\Delta G$$

Question 17

Which of the following best describes the function of a phosphatase enzyme?

Accepted Answer

It removes a phosphate group from a molecule via hydrolysis.

Question 18

According to Markovnikov’s rule, when water is added to a 1-alkene in the presence of an acid catalyst, where does the -OH group attach?

Accepted Answer

To the second carbon (not the end carbon) of the double bond.

Question 19

Which of the following is true about the coupling of endergonic and exergonic reactions in biological systems?

Accepted Answer

An endergonic reaction can proceed if it is coupled to an exergonic reaction with a larger negative $$\Delta G.$$

Question 20

Which of the following best describes a redox reaction in organic chemistry?

Accepted Answer

A reaction in which electrons are transferred, often involving changes in C-H and C-O bonds.

Chapter 5: Chemical Reactions – Thermodynamics, Kinetics, and Reaction Types

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