AP Chem Enthalpy Entropy and Gibbs Free Energy

Which reaction has the greatest increase in entropy?

• 2H₂0 (l) --> 2H_{2 (g)} + O_{2 (g)}

• 2H₂O(g)--> 2H₂(g) + O₂(g)

• H₂O(g) --> H₂O(l)

• H₂O(l) H₂O(s)

Which process is accompanied by a decrease in entropy?

• boiling of water

• condensing of water vapor

• subliming of iodine (solid directly to gas)

• melting of ice

Systems in nature tend to undergo changes toward

• lower energy and less disorder

• lower energy and more disorder

• higher energy and less disorder

• higher energy and more disorder

Tags

NGSS.HS-PS3-4

Given the change of phase:

CO₂(g) —> CO₂(s)

As CO₂(g) changes to CO₂(s), the entropy of the system

• decreases

• increases

• remains the same

Which phase change represents a decrease in entropy?

• solid to liquid

• gas to liquid

• liquid to gas

• solid to gas

Identify whether the following result in an increase or decrease in entropy:

Gas --> Liquid --> solid

• increase

• decrease

Entropy increases from solid, liquid to gas. Why?

• Molecular disorder increases
• Molecular randomness decreases
• Molecules are more energetic
• Molecules are more reactive

Tags

NGSS.HS-PS1-3

NGSS.HS-PS3-2

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

• It will be spontaneous at all temperatures.
• It will be nonspontaneous at all temperatures.
• It will be spontaneous at low temperatures.
• It will be spontaneous at high temperatures.

Two factors that determine the spontaneity of a reaction are:

• entropy and free energy
• enthalpy and free energy
• entropy and enthalpy
• endothermic and exothermic

Reactions tend to be spontaneous if they are exothermic.

• True
• False

Tags

NGSS.HS-PS1-4