AP Chemistry Gibbs Free Energy and Equilibrium Constants

What does Gibbs Free Energy tell us?

• How much energy is given off by a reaction.

• The tendency of a reaction to become "random"

• The feasibility of a reaction.

• The degree of disorder

What information do we need to perform a calculation of Gibbs Free Energy?

• Enthalpy of the reaction.

• Entropy of the reaction.

• The temperature of the reaction in Kelvin.

• All of the above are needed.

Spontaneous reactions may be extremely slow.

• True
• False

Tags

NGSS.HS-PS1-5

Which of the following would most likely lead to a spontaneous reaction.

• A large negative enthalpy.

• A small negative enthalpy.

• A large positive enthalpy.

• A small positive enthalpy.

Tags

NGSS.HS-PS1-4

A reaction has a positive ΔH and a positive ΔS. Which of the following is likely?

• It will be spontaneous at all temperatures.

• The reaction is never feasible.

• It will be spontaneous at low temperatures.

• It will be spontaneous at high temperatures.

Your enthalpy is high and negative but your entropy is also negative. What type of temperature would you want to get a spontaneous reaction?

• low

• high

• Feasible at all temperatures

• Never feasible

Your enthalpy is positive and your entropy is positive. What type of temperature would you want to ensure a spontaneous reaction.

• very high

• very low

Which combination of ΔH and ΔS NEVER has a spontaneous reaction?

• +ΔH and +ΔS

• +ΔH and -ΔS

• -ΔH and -ΔS

• -ΔH and +ΔS

The formation ½ A₂ + 2 B₂ + C --> CAB₄ has an enthalpy of formation of -104 kJ and a change in entropy of -60.8 J/K at 30 °C. What is the free energy and spontaneity of the reaction?

• -85.6 kJ, spontaneous

• -18.3 kJ, not spontaneous

• +18.3 kJ, spontaneous

• +85.6 kJ, not spontaneous

Tags

NGSS.HS-PS1-4

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 +