Thermodynamics Flashcards

1
Q

Draw the reduction energy level diagram

A

Reduction occurs when the energy of the electrode increases above the lowest vacant molecular orbital of the compound

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2
Q

Draw the oxidation energy level diagram

A

Oxidation occurs when the energy of the electrode dips below the highest occupied molecular orbital of the compound

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3
Q

Write the Change in Gibbs Energy equation and denote the symbols

A
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4
Q

Write the Change in Gibbs Energy equation from the differential form

A
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5
Q

What is the equilibrium potential directly related to?

A

Free energy change

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6
Q

What are the conditions of standard lectrode potentials?

A
  1. At equilibrium.
  2. Potential associated with a reduction reaction when at 1M, 1 atm, and at 25 °C
  3. Measured with respect to standard hydrogen electrode (SHE)

It is the quantitative measure for the thermodynamic tendency of a redox couple to undergo reduction or oxidation

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7
Q

What is a oxidizing agent (oxidant)?

A

Molecule that gains electrons

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8
Q

What is a reducing agent (reductant)?

A

Molecule that loses electrons

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9
Q

What is the equation for equilibrium potential of a cell?

A
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10
Q

What would the values of ΔG and Ecell be so that the reaction is feasible (proceeds spontaneously)?

A

Ecell must be positive
So ΔG must be negative

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11
Q

Comparing two Ecell values - which one would get oxidised (loses electrons)?

A

Ecell value with lower standard reduction potential
Higher value gets reduced

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12
Q

What is the Nernst equation and what does it account for?

A

Nerst equation shows the potential of the electrochemical cell depends on the composition

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13
Q

What is the thermodynamic reaction quotient equation?

A
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14
Q

What do thermodynamics / Nerst equation not consider?

A
  1. Transition states, mass transfer, energy barriers (kinetic effects)
  2. Internal resistance: solutions are not perfect conductors
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15
Q

When will thermodynamics / Nerst model work?

A

Before the current flows (open cicuit)
Nerst model is based of thermodynamics (NOT kinetics!) - static modelrather than dynamic rate model
Problem occurs when we use current

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