Gibbs Energy and Reaction Spontaneity

The video explores the spontaneity of chemical reactions based on the signs of enthalpy and entropy. It explains how Gibbs energy determines whether a process is spontaneous, with a focus on endergonic and exergonic reactions. The video also covers the impact of temperature on reaction spontaneity, discussing endothermic and exothermic reactions, and how entropy changes affect Gibbs energy. Different combinations of enthalpy and entropy signs are analyzed to determine reaction favorability at various temperatures.

What determines the spontaneity of a process in a closed system at constant temperature and pressure?

• Gibbs energy

• Enthalpy

• Entropy

• Temperature

What is the characteristic of an endergonic reaction?

• It releases energy to the surroundings.

• It has a Gibbs energy change greater than zero.

• It is always exothermic.

• It is spontaneous in the forward direction.

How does an exergonic reaction behave in terms of Gibbs energy?

• Gibbs energy is irrelevant.

• Gibbs energy increases.

• Gibbs energy remains constant.

• Gibbs energy decreases.

What happens to Gibbs energy when a reaction is entropically favored?

• Gibbs energy decreases.

• Gibbs energy increases.

• Gibbs energy remains unchanged.

• Gibbs energy becomes zero.

What is the effect of a positive enthalpy change on a reaction?

• The reaction absorbs heat.

• The reaction is always spontaneous.

• The reaction is exothermic.

• The reaction releases heat.

In a reaction with negative enthalpy and positive entropy, what is the Gibbs energy sign at all temperatures?

• Positive

• Negative

• Zero

• Undefined

What is the Gibbs energy sign for an endothermic and entropically disfavored reaction at all temperatures?

• Zero

• Positive

• Variable

• Negative

How does temperature affect an endothermic reaction that is entropically favored?

• It remains non-spontaneous at all temperatures.

• It becomes more spontaneous at high temperatures.

• It becomes spontaneous at low temperatures.

• It becomes less spontaneous at high temperatures.

What happens to an exothermic reaction that is entropically disfavored as temperature increases?

• It remains spontaneous.

• It becomes less spontaneous.

• It becomes non-spontaneous at low temperatures.

• It becomes more spontaneous.

When enthalpy and entropy have the same sign, what determines the reaction's spontaneity at high temperatures?

• Enthalpy

• Entropy

• Pressure

• Volume