MATS_15201: Equilibrium Thermodynamics pt. 2

Question 1

On what side are the electrons

for a reduction reaction?

Answer 1

Left

Question 2

On what side are the electrons

for an oxidation reaction?

Answer 2

Right

Question 3

What effect does reduction have on the oxidation state of an element (or specie)?

Answer 3

It decreases it

Question 4

What effect does oxidation have on the oxidation state of an element (or specie)?

Answer 4

It increases it

Question 5

Where does oxidation take place:

Anode or Cathode?

Answer 5

Anode

Remember Red Cat ate An Ox.

Question 6

Where does reduction take place:

Anode or Cathode?

Answer 6

Cathode

Remember Red Cat ate An Ox.

Question 7

What is the sign on reductive current, positive or negative?

Answer 7

Negative

Question 8

What is another name for reductive current?

Answer 8

Cathodic current

Question 9

What is a real solution?

Answer 9

One where the enthalpy change on mixing is not equal to zero

Question 10

True or False:

A regular soluton is the same thing as a real solution?

Answer 10

False

A regular solution is a type of real solution

Question 11

What is Upper Critical Solution Temperature (UCST)?

Answer 11

The temperature below which a regular solution no longer exists in a single phase but as a mixture of two different phases with different compositions

Question 12

What is the equation for UCST?

Answer 12

T_c = ϐ/2R

where ϐ is the interaction parameter

Question 13

What is the equation for the relationship between Gibbs Free Energy and Equilibrium Constant?

Answer 13

Δ_rG^o = -RT ln(K)

Question 14

What is the equation for the relationship between Gibbs Free Energy and Reaction Quotient (Q)?

Answer 14

Δ_rG^o - Δ_rG= -RT ln(Q)

Note the difference

Question 15

What is the equation for the relationship between Standard Gibbs Free Energy and Electrochemical Potential (E)?

Answer 15

Δ_rG^o = -zFE^o

Where z is the no of electrons and F is Faraday’s constant (96 500)

Question 16

What

Question 17

What is the slope for a graph of Δ_rG^o against T?

Answer 17

-Δ_rS^o

Question 18

What is the value of 1 bar in Pascals?

Answer 18

10⁵ Pa

Pa and Nm^-2 are the same

Question 19

True or False:

1 bar is approximately equal to 1 atm

Answer 19

True

Question 20

In what reference is ‘fusion’ defined:

Melting or Freezing?

Answer 20

Melting

Question 21

What is the sign on reductive current?

positive or negative?

Answer 21

Negative

Question 22

Why isn’t using the standard hydrogen electrode as a reference realistically reliable?

Answer 22

Hydrogen is a very combustible gas

Question 23

What does K value > 1 say about the equilibrium position of a system?

Answer 23

It tends towards the right (product side) of the equation

Question 24

What does K value < 1 say about the equilibrium position of a system?

Answer 24

It tends towards the left (reactant side) of the equation

Question 25

What does K value = 1 say about the equilibrium position of a system?

Answer 25

The system is at equilibrium

Question 26

What is the relationship between log₁₀(A) and ln(A)?

Answer 26

**ln(A) = log₁₀(A) x 2.303**

Question 27

What was the Nernst Equation developed for?

Answer 27

To calculate the electrochemical potential of a system not under standard conditions

Question 28

State the Nernst Equation | one form of it at least

Answer 28

E = E₀ -(RT/zF) x ln(Q) ## Footnote Q: Reaction quotient F: Faraday's constant z: Electron no. Temp is in **Kelvin**

Question 29

What is another name for electrochemical potential?

Answer 29

Cell potential

Question 30

What does a **positive** E^o_cell value say about an electrochemical reaction in a galvanic cell?

Answer 30

The reaction will proceed *spontaneously*

Question 31

What does a **negative** E^o_cell value say about an electrochemical reaction in a galvanic cell?

Answer 31

The reaction **is not spontaneous** and will require an input of energy to occur

Question 32

# Which reaction is more likely to occur when: The value of E^o for an atom/ion system is **more negative**? **Oxidation** or **Reduction**

Answer 32

Oxidation ## Footnote E^o values are standard reduction potentials, the more negative that is, the less likely that this is to be reduced