Gibbs Free Energy

1. Calculate the standard entropy change for the following reaction: Cu(s)+1/2 O₂(g) → CuO(s). Given that

S⁰ (Cu(s)) = 33.15 J/K*mol

S⁰ (O₂(g)) = 205.14 J/K*mol

S⁰ (CuO(s)) = 42.5 J/K*mol

• 195.66 J/K.mol

• 93.09 J/K.mol

• -93.09 J/K.mol

• +195.66 J/K.mol

1. Given the following information, calculate ΔG⁰ for the reaction below at 25⁰C:

SnCl₄(l) + 2 H₂0(l) → SnO₂(S) + 4HCl(g),

ΔH⁰=133.0 kJ and ΔS⁰ =401.5 J/K

• -252.6 kJ

• -13.4 kJ

• 13.4 kJ

• 252.6 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Given the following information, calculate ΔG⁰ for the following reaction below at 25⁰ C: 2H₂O₂(l) →2H₂O(l) + O₂(l)

H⁰ (H₂O₂(l)) = -187.5 kJ/mol, S⁰ (H₂O₂(l)) = 109.6 J/K*mol

H⁰ (H₂O(l)) = -285.8 kJ/mol, S⁰ (H₂O(l)) = 69.9 J/K*mol

H⁰ (O₂(l)) = -, S⁰ (O₂(l)) = 205.1 J/K*mol

• -37700 kJ

• -342.6 kJ

• +233.5 kJ

• -233.5 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

For the process at 25⁰C : I₂(g) →I₂(s). What are the signs for ΔG, ΔH and ΔS?

• ΔG ΔH ΔS

  + - -

• ΔG ΔH ΔS

  - - -

• ΔG ΔH ΔS

  - + +

• ΔG ΔH ΔS

  - + +

If a process is exothermic and not spontaneous, then what must be true?

• ΔS > 0

• ΔH > 0

• ΔG = 0

• ΔS < 0

In which of the following reactions do you expect to have a decrease in entropy?

• Fe(s) →Fe(l)

• H₂O₂(l) →2H₂O(l) +O₂(g)

• 2Fe(s) +3/2O₂(g)→Fe₂O₃(s)

• HF(l) →HF(g)

The enthalpy of vaporization of methanol (CH₃0H) is 35.3 kJ/mol at the boiling point of 64.2 ⁰C. Calculate the entropy change for methanol going from a liquid to vapor.

• 600 J/K.mol

• 551 J/K.mol

• 105 J/K.mol

• -105 J/K.mol

Tags

NGSS.HS-PS3-2

NGSS.HS-PS3-4

If ΔH and ΔS are both negative or positive, then ΔG has a -------------------sign.

• Positive

• Negative

• Large

• Variable

At what temperature would a given reaction become spontaneous if ΔH =+119kJ and ΔS=+263J/K.mol

• 452 K

• 2210 K

• 382 K

• 363 K

For any reaction at equilibrium, which of the following is true?

• ΔH<0

• ΔS< 0

• ΔG=0

• ΔS=0