Chapter 14 Multiple-choice questions

. Energy is measured in which of the following units?

Kelvin

Joule

Pascal

mol

. The formation of a chemical bond releases energy. True or false?

True

False

. Which one of the following statements regarding energy is false?

The total energy in a chemical universe (a system and its surroundings) is constant

Energy can be converted from one form to another

The energy stored in chemical bonds is referred to as kinetic energy

An object suspended in the air has more energy than an object lying on the ground

. In which direction does the transfer of energy as heat happen spontaneously?

From cold to hot

From hot to cold

. Which one of the following statements best describes the enthalpy change of a reaction?

The energy released when chemical bonds are formed during a chemical reaction

The energy consumed when chemical bonds are broken during a chemical reaction

The difference between the energy released by bond formation and the energy consumed by bond cleavage during a chemical reaction

The increase in disorder of the system as a reaction proceeds

. Enthalpy is represented by which of the following symbols?

H

K

<>S

U

. Which of the following terms describes a reaction in which there is a net transfer of energy from a system to its surroundings – that is, where more energy is released by bond formation than is consumed by bond cleavage?

Exothermic

Endothermic

. The enthalpy of combustion of glucose is -2808 kJ mol^-1. Which one of the following statements regarding this process is false?

The products of the combustion of glucose are less stable than glucose itself

This process is exothermic

Overall, energy is liberated when this process happens

. When a polypeptide chain folds to adopt its characteristic three-dimensional state, its entropy increases. True or false?

True

False

. Which of the following statements regarding the Gibbs free energy change for a reaction is false?

The Gibbs free energy change is the proportion of the enthalpy change of a reaction that is used to increase the entropy.

If the Gibbs free energy change for a reaction is negative, the reaction happens spontaneously.

The Gibbs free energy is represented by the symbol ∆G

A reaction with a negative Gibbs free energy change of reaction is called an exergonic reaction.

. Which of the following statements regarding entropy is correct?

For a process to be spontaneous, the overall entropy change must be positive

For a process to be spontaneous, the overall entropy change must be negative

. Hess's Law describes how the enthalpy change for a reaction is related to the standard enthalpies of formation of the reactants and products, and can be summarised by the cycle shown here. But which of the following options allocates the correct labels to the processes denoted 1, 2 and 3?

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