Thermodynamics

Question 1

Spontaneous Change

Answer 1

Process that takes place without a continuous input of energy from an external source

Question 2

Nonspontaneous Process

Answer 2

Process that requires continual input of energy from an external source

Question 3

Reversible Process

Answer 3

Process that takes place so slowly as to be capable of reversing direction in response to an infinitesimally small change in conditions; hypothetical construct that can only be approximated by real processes

Question 4

Entropy (S)

Answer 4

State function that is a measure of the matter and/or energy dispersal within a system, determined by the number of system microstates; often described as a measure of the disorder of the system

Question 5

Microstate

Answer 5

Possible configuration or arrangement of matter and energy within a system

Question 6

Second Law of Thermodynamics

Answer 6

All spontaneous processes involve an increase in the entropy of the universe

Question 7

Third Law of Thermodynamics

Answer 7

Entropy of a perfect crystal at absolute zero (0 K) is zero

Question 8

Standard Entropies (S^*)

Answer 8

Entropy for one mole of a substance at 1 bar pressure; tabulated values are usually determined at 298.15K

Question 9

Standard Entropy Change

Answer 9

Change in entropy for a reaction calculated using the standard entropies

Question 10

Gibbs Free Energy Change (G)

Answer 10

Thermodynamic property defined in terms of system enthalpy and entropy; all spontaneous processes involve a decrease in G

Question 11

Standard Free Energy Changes (deltaG^*)

Answer 11

Change in free energy for a process occurring under standard conditions (1 bar pressure for gases, 1 M concentration for solutions)

Question 12

Standard Free Energy of Formation (deltaGf^*)