Lecture 3

Question 1

What is the pH in standard conditions?

Answer 1

pH 0

Question 2

what is the most stable oxidation state on a frost diagram?

Answer 2

lowest point on the plot

Question 3

which species is susceptible to disproportionation on a frost diagram?

Answer 3

point sitting above the straight line joining neighbours

Question 4

How do you calculate the E value of 2 opposite species on a frost diagram?

Answer 4

gradient of the line joining the species

Question 5

What is the Nernst equation?

Answer 5

E = E* - RT/nF lnQ

E= potential under nonstandard conditions
E*= standard potential
R= molar gas constant
T= temp
Q= reaction quotient

Question 6

What is Q? (Nernst equation)

Answer 6

Q= [products]/[reactants]

ignore solid species
gaseous species use partial pressure

Question 7

Whats the gradient of a reversible reaction with m protons and n electrons?

Answer 7

For a reversible redox reaction that involves m protons and n electrons, the electrode potential has a gradient of -m/n x 59mV ph-1 at 298K

Question 8

When is Ecathode more favourable?

Answer 8

When the Ecathode value is more positive its more favourable