Entropy
What happens to the entropy (SSS) when a solid dissolves in water?
A) Entropy decreases
B) Entropy remains the same
C) Entropy increases
D) Entropy depends on the type of solid
C) Entropy increases
What is the unit of entropy (SSS) in the SI system?
A) Joules (J)
B) Joules per mole (J/mol)
C) Joules per kelvin (J/K)
D) Joules per mole per kelvin (J/mol·K)
D) Joules per mole per kelvin (J/mol·K)
What does a negative Gibbs free energy change (ΔG\Delta GΔG) indicate about a chemical reaction?
A) The reaction is at equilibrium
B) The reaction is non-spontaneous
C) The reaction is spontaneous
D) The reaction is endothermic
C) The reaction is spontaneous
At equilibrium, what is the value of ΔG?
A) Positive
B) Negative
C) Zero
D) Undefined
C) Zero
What does entropy (SSS) measure in a system?
A) Energy content
B) Disorder or randomness
C) Temperature
D) Reactivity
B) Disorder or randomness
Which of the following processes leads to an increase in entropy?
A) Freezing water into ice
B) Condensation of steam into water
C) Melting ice into water
D) Compressing a gas into a smaller volume
C) Melting ice into water
Which equation correctly represents the Gibbs free energy change?
A) ΔG=ΔH−TΔS
B) ΔG=ΔH+TΔS
C) ΔG=ΔS−TΔH
D) ΔG=TΔS−ΔH
A) ΔG=ΔH−TΔS
How does a catalyst affect the Gibbs free energy change of a reaction?
A) Increases ΔG
B) Decreases ΔG
C) Does not change ΔG
D) Depends on the reaction
C) Does not change ΔG
Which of the following has the highest entropy?
A) Ice at 0°C
B) Water at 25°C
C) Water vapor at 100°C
D) Liquid nitrogen at -196°C
C) Water vapor at 100°C
Which of the following has the lowest entropy?
A) A solid crystal at 0 K
B) A liquid at room temperature
C) A gas at high temperature
D) A dissolved salt in water
A) A solid crystal at 0 K
For a reaction with ΔH>0> 0ΔH>0 and ΔS>0> 0ΔS>0, under what condition will it be spontaneous?
A) At low temperatures
B) At high temperatures
C) At all temperatures
D) At no temperature
B) At high temperatures
A certain reaction is spontaneous at low temperatures but becomes non-spontaneous at high temperatures. What must be true about the entropy change (ΔS\Delta SΔS) of the reaction?
A) ΔS is positive
B) ΔS is negative
C) ΔS is zero
D) There is no relationship between ΔS and temperature in this case
B) ΔS is negative
Which state of matter has the highest entropy?
A) Solid
B) Liquid
C) Gas
D) Plasma
C) Gas
What is the entropy change (ΔS\Delta SΔS) when a gas expands into a larger volume?
A) Positive
B) Negative
C) Zero
D) Depends on the temperature
A) Positive
Which of the following statements is true regarding Gibbs free energy?
A) It predicts the rate of a reaction
B) It indicates the spontaneity of a reaction
C) It measures the heat content of a system
D) It quantifies the disorder of a system
B) It indicates the spontaneity of a reaction
Which of the following scenarios would most likely result in a Gibbs free energy change (ΔG\Delta GΔG) that is temperature-dependent?
A) A reaction that releases heat (ΔH<0< 0ΔH<0) and increases disorder (ΔS>0> 0ΔS>0)
B) A reaction that absorbs heat (ΔH>0>0ΔH>0) and increases disorder (ΔS>0> 0ΔS>0)
C) A reaction that releases heat (ΔH<0< 0ΔH<0) and decreases disorder (ΔS<0< 0ΔS<0)
D) A reaction that absorbs heat (ΔH>0> 0ΔH>0) and decreases disorder (ΔS<0< 0ΔS<0)
B) A reaction that absorbs heat (ΔH>0>0ΔH>0) and increases disorder (ΔS>0> 0ΔS>0)