MATS_15201: Equilibrium Thermodynamics pt. 2 Flashcards
On what side are the electrons
for a reduction reaction?
Left
On what side are the electrons
for an oxidation reaction?
Right
What effect does reduction have on the oxidation state of an element (or specie)?
It decreases it
What effect does oxidation have on the oxidation state of an element (or specie)?
It increases it
Where does oxidation take place:
Anode or Cathode?
Anode
Remember Red Cat ate An Ox.
Where does reduction take place:
Anode or Cathode?
Cathode
Remember Red Cat ate An Ox.
What is the sign on reductive current, positive or negative?
Negative
What is another name for reductive current?
Cathodic current
What is a real solution?
One where the enthalpy change on mixing is not equal to zero
True or False:
A regular soluton is the same thing as a real solution?
False
A regular solution is a type of real solution
What is Upper Critical Solution Temperature (UCST)?
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
What is the equation for UCST?
Tc = ϐ/2R
where ϐ is the interaction parameter
What is the equation for the relationship between Gibbs Free Energy and Equilibrium Constant?
ΔrGo = -RT ln(K)
What is the equation for the relationship between Gibbs Free Energy and Reaction Quotient (Q)?
ΔrGo - ΔrG= -RT ln(Q)
Note the difference
What is the equation for the relationship between Standard Gibbs Free Energy and Electrochemical Potential (E)?
ΔrGo = -zFEo
Where z is the no of electrons and F is Faraday’s constant (96 500)
What
What is the slope for a graph of ΔrGo against T?
-ΔrSo
What is the value of 1 bar in Pascals?
105 Pa
Pa and Nm-2 are the same
True or False:
1 bar is approximately equal to 1 atm
True
In what reference is ‘fusion’ defined:
Melting or Freezing?
Melting
What is the sign on reductive current?
positive or negative?
Negative
Why isn’t using the standard hydrogen electrode as a reference realistically reliable?
Hydrogen is a very combustible gas
What does K value > 1 say about the equilibrium position of a system?
It tends towards the right (product side) of the equation
What does K value < 1 say about the equilibrium position of a system?
It tends towards the left (reactant side) of the equation
What does K value = 1 say about the equilibrium position of a system?
The system is at equilibrium
What is the relationship between log10(A) and ln(A)?
ln(A) = log10(A) x 2.303
What was the Nernst Equation developed for?
To calculate the electrochemical potential of a system not under standard conditions
State the Nernst Equation
one form of it at least
E = E0 -(RT/zF) x ln(Q)
Q: Reaction quotient
F: Faraday’s constant
z: Electron no.
Temp is in Kelvin
What is another name for electrochemical potential?
Cell potential
What does a positive Eocell value say about an electrochemical reaction in a galvanic cell?
The reaction will proceed spontaneously
What does a negative Eocell value say about an electrochemical reaction in a galvanic cell?
The reaction is not spontaneous and will require an input of energy to occur
Which reaction is more likely to occur when:
The value of Eo for an atom/ion system is more negative?
Oxidation or Reduction
Oxidation
Eo values are standard reduction potentials, the more negative that is, the less likely that this is to be reduced
