Question 1

Which of the following statements best describes the relationship between the signs of $$\Delta G$$, $$\Delta H$$, and $$\Delta S$$ for a reaction that is spontaneous at all temperatures?

Accepted Answer

$$\Delta H  0$$, $$\Delta G \u003c 0$$

Question 2

Given the equation $$\Delta G = \Delta H - T\Delta S$$, which change will always make a reaction more favorable as temperature increases?

Accepted Answer

A positive $$\Delta S$$

Question 3

A reaction has $$\Delta H = +50\ \mathrm{kJ/mol}$$ and $$\Delta S = +0.2\ \mathrm{kJ/(mol\cdot K)}. At $$what temperature does the reaction become spontaneous?

Accepted Answer

$$T \u003e 250\ \mathrm{K}$$

Question 4

Which of the following best describes the conceptual meaning of the Arrhenius equation?

Accepted Answer

It explains how temperature and activation energy affect the rate constant.

Question 5

Which of the following is the correct formula for calculating the equilibrium constant $$K_{eq}$$ from $$\Delta G at $$temperature $$T$$?

Accepted Answer

$$K_{eq} = e$$^{-\Delta G/RT}$$

Question 6

Which of the following is true about bond dissociation energies in the context of endothermic and exothermic reactions?

Accepted Answer

Bond breaking consumes energy, while bond formation releases energy.

Question 7

Using the Hammond Postulate, which halogenation (bromination or chlorination) of alkanes has a more product-like transition state?

Accepted Answer

Bromination

Question 8

Which of the following molecules is a meso compound?

Accepted Answer

2,3-dibromobutane

Question 9

A sample contains 70% of one enantiomer and 30% of the other. What is the enantiomeric excess (ee)?

Accepted Answer

40%

Question 10

Which of the following best describes a chiral molecule?

Accepted Answer

A molecule that is not superimposable on its mirror image

Question 11

Which of the following is the weakest bond based on bond dissociation energies?

Accepted Answer

C-Br

Question 12

Which of the following is NOT a requirement for a molecule to be optically active?

Accepted Answer

It must be a meso compound.

Question 13

Which of the following best describes atom economy in a chemical reaction?

Accepted Answer

The percentage of reactant atoms incorporated into the desired product.

Question 14

Which of the following is true about entropy ($$S) in $$chemical reactions?

Accepted Answer

Entropy is a measure of disorder or randomness.

Question 15

Which of the following is the correct expression for $$\Delta G in $$terms of $$T$$ and $$K_{eq}$$?

Accepted Answer

$$\Delta G = -RT \ln K_{eq}$$

Question 16

Which of the following best describes a rate-limiting step in a reaction coordinate diagram?

Accepted Answer

The step with the highest activation energy

Question 17

Which of the following molecules contains an asymmetric (chiral) carbon?

Accepted Answer

2-butanol

Question 18

Which of the following is true about chirality in molecules without asymmetric (chiral) carbons?

Accepted Answer

Chirality can arise from overall molecular symmetry, such as in allenes.

Question 19

Which of the following is the correct formula for calculating optical rotation ($$\alpha) of a $$mixture, given the observed rotation ($$\alpha_{obs}$$), path length ($$l in dm$$), and concentration ($$c in g/mL$$)?

Accepted Answer

$$[\alpha] = \alpha_{obs} / (l \cdot c)$$

Question 20

Which of the following is true about the equilibrium constant $$K_{eq}$$ for an exergonic reaction?

Accepted Answer

$$K_{eq} \u003e 1$$

Organic Chemistry: Thermodynamics, Kinetics, Stereochemistry, and Atom Economy Study Guide

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