Lecture 6 - Thermodynamics

Question 1

If ΔG is negative, energy is released. This is called an _____ reaction

Answer 1

exergonic

Question 2

If ΔG is positive, energy is required. This is called an _____ reaction

Answer 2

endergonic

Question 3

This symbol represents Gibbs free energy change under a set of specified conditions.

Answer 3

ΔG

Question 4

This symbol represents Gibbs free energy change under standard conditions (25⁰ C, 1 atm, reactants and products are at 1 M; [H+]= 1M, pH=0)

Answer 4

ΔG⁰

Question 5

This symbol represents Gibbs free energy change under at STP, pH=7

Answer 5

ΔG⁰’

Question 6

Determine ΔG⁰’ using ΔGf⁰ values.

aA+bB –> cC+dD

Answer 6

ΔG⁰’ = [c( ΔGf⁰)c + d( ΔGf⁰)D] - [a( ΔGf⁰)A + b( ΔGf⁰)B]

Question 7

Given temperature and reactant/product concentrations, be able to calculate ΔG⁰ values.

Answer 7

ΔG⁰ = ΔG⁰’ + RT ln([C]ᶜ [D]ᵈ/[A]ᵃ [B]ᵇ)

Question 8

R =

Answer 8

8.31 J/mol*K

universal gas constant

Question 9

T =

Answer 9

temperature in K

T(K) = T(C) + 273.15

Question 10

[A], [B], [C], [D] are _____ concentrations

Answer 10

molar (mol/L)

Question 11

Reactions with a _____ reactant concentration and _____ product concentration will require more free energy.

Answer 11

high, low

Question 12

Calculate ΔG⁰’ using differences in reduction potential values (ΔE₀’).

Answer 12

ΔG⁰’ = -nFΔE₀’

Question 13

n =

Answer 13

number of electrons transferred

Question 14

F = Faradays constant

Answer 14

96480 J/V*mol

Faradays constant

Question 15

ΔE₀’ =

Answer 15

E₀ of electron acceptor - E₀ of electron donor