AP Style Questions Unit 9 Part 3

Gibbs Free Energy and Thermodynamic Favorability

1. Under what condition is a reaction considered thermodynamically favorable?

a) ΔG > 0
b) ΔG = 0
c) ΔG < 0
d) ΔG ≠ 0

2. What is the value of ΔG at equilibrium?

a) Positive
b) Negative
c) Zero
d) Variable

3. Which condition ensures a reaction is non-favored at all temperatures?

a) ΔH > 0 and ΔS > 0
b) ΔH < 0 and ΔS < 0
c) ΔH > 0 and ΔS < 0
d) ΔH < 0 and ΔS > 0

4. When does a reaction become favorable at high temperatures?

a) ΔH > 0 and ΔS > 0
b) ΔH < 0 and ΔS < 0
c) ΔH > 0 and ΔS < 0
d) ΔH < 0 and ΔS > 0

5. What equation relates Gibbs Free Energy (ΔG) to enthalpy (ΔH) and entropy (ΔS)?

a) ΔG = ΔH + TΔS
b) ΔG = ΔH - TΔS
c) ΔG = TΔH - ΔS
d) ΔG = ΔS - TΔH

6. What type of reaction releases free energy (ΔG < 0)?

a) Endergonic
b) Exergonic
c) Isothermal
d) Adiabatic

7. Which type of reaction requires an input of free energy (ΔG > 0)?

a) Exergonic
b) Endergonic
c) Spontaneous
d) Isothermal

8. What does a negative ΔG indicate about the stability of products compared to reactants?

a) Products are less stable
b) Products are equally stable
c) Products are more stable
d) Stability cannot be determined

9. How do coupled reactions make non-favored processes thermodynamically favorable?

a) By increasing entropy
b) By decreasing enthalpy
c) By combining an exergonic reaction with an endergonic one
d) By raising the temperature

10. What determines the sign of ΔG in a chemical reaction?

a) Temperature only
b) Enthalpy only
c) Entropy only
d) The balance between enthalpy and entropy