Thermodynamics

Question 1

1st Law of Thermodynamics

Answer 1

The internal energy of a system remains constant

Question 2

Types of systems

Answer 2

Open: Allows energy and matter exchange
Closed: Allows energy transfer but not matter transfer
Isolated: Allows neither energy or matter transfer

Question 3

State function

Answer 3

Depends only on the final and initial states, not the path followed

Question 4

Non-state function

Answer 4

The path followed matters, not only the final and initial states

Question 5

Universal Gas Constant (R)

Answer 5

8.314 J⋅K−1⋅mol−1

Question 6

Work (w)

Answer 6

Energy dispersed as non-random motion, not a state function

Question 7

Heat (q)

Answer 7

Energy dispersed as random motion, not a state function

Question 8

Heat Capacity (C)

Answer 8

The heat capacity of a substance is the heat required to change its temperature by 1 Kelvin. C=q/(ΔT*n)

Question 9

Internal Energy (u)

Answer 9

u=w+q, u is an extensive property (change observed without a reaction, depends on the amount of matter that is present) and is a state function

Question 10

Kirchhoff’s Law

Answer 10

Allows calculation of reaction enthalpies at different temperatures. ΔH(T2) = ΔH(T1) + (T2-T1) [ΣCp(products)-ΣCp(reactants)] Note: Cp = Heat capacity

Question 11

2nd Law of Thermodynamics

Answer 11

The entropy of an isolated system increases during any spontaneous process

Question 12

Clausius inequality

Answer 12

ΔS=q/t

Question 13

Entropy

Answer 13

Gradual decline into disorder, entropy is a state function

Question 14

Entropy of fusion

Answer 14

ΔSfus=ΔHfus(Tfus)/Tfus

Question 15

Gibbs free energy

Answer 15

ΔG=ΔH-TΔS

Question 16

3rd Law of Thermodynamics

Answer 16

The entropy of a system approaches a constant value as its temperature approaches absolute zero.