Quiz | Chemical Thermodynamics


Which of the following statements best describes the Second Law of Thermodynamics?

The energy of the universe is constant

Energy can neither be created nor destroyed

The total entropy of an isolated system can never decrease over time

At absolute zero, the entropy of a perfect crystal is considered to be zero


What is the expression of the Gibbs energy change?

ΔGrxn = ΔHrxn + TΔSrxn

ΔGrxn = ΔHrxn - TΔSrxn

ΔGrxn = ΔHrxn - RTΔSrxn

ΔGrxn = ΔHrxn/T + ΔSrxn


Which of the following criteria for reaction spontaneity is incorrect?

ΔGrxn = 0: reaction is at equilibrium

ΔGrxn < 0: reaction is spontaneous and additional products can form

Q < K: reaction proceeds spontaneously from right to left

None of the above


Which of the following statements is always true when a reversible chemical reaction has attained equilibrium?

The Gibbs free energy of the system reaches a minimum

All reactants have been converted to products

The forward reaction dominates over the reverse reaction

The reaction quotient equal to 0


What is the relationship between the equilibrium constant K and the temperature T?

ln K and T are proportional

ln K and -T are proportional

K and ln T are proportional

ln K and 1/T are proportional


When does the entropy usually increase?

A molecule is broken into 2 or more molecules

A solid changes to a liquid

A liquid changes to a gas

All of the above situations