gibbs energy and the second law

Question 1

Where do you find the values for Sm?

Answer 1

Data card

Question 2

How do you convert ΔrxnH to ΔSsurr?

Answer 2

ΔrxnH is in kJ mol-1 so you need to divide by temperature

Question 3

What is the equation for Gibbs energy?

Answer 3

Gsys = Hsys - TSsys

Question 4

What is the equation for change in gibbs energy when there is a constant temperature?

Answer 4

ΔG = ΔH - TΔS

Question 5

What is ΔStotal?

Answer 5

ΔSsurr + ΔSsystem

Question 6

What values can ΔSsurr + ΔSsystem have?

Answer 6

Positive or zero

Question 7

How do you work out the maximum useful work?

Answer 7

-(ΔG)p,T = w’rev

Question 8

What is w’?

Answer 8

Useful work

Question 9

What is expansion work?

Answer 9

pΔV

Question 10

What is the standard Gibbs energy of formation? (ΔfG)

Answer 10

The Gibbs energy of reaction to form the compound from the elements in their reference states
These values are tabulated

Question 11

What equation is used to work out the Gibbs energy of reaction?

Answer 11

ΔrxnG = ΣvΔfGm (products) - ΣvΔfGm (reactants)

Question 12

What equation is used to work out the energy of electrochemical cells?

Answer 12

E = Er - El

Question 13

What equation can be used to work out useful work involving electrochemical cells?

Answer 13

w’ = QE = - (ΔG)p,t

Question 14

What is the equation for Faraday’s law?

Answer 14

Q = nF

Question 15

What is Faraday’s constant?

Answer 15

96485.3 s A/mol

Question 16

What relationship connects Gibbs energy and potential?

Answer 16

(ΔG)p,T = -nFE