Entropy

Which of these processes represents a decrease in entropy?

• sublimation of CO₂

• boiling water

• condensation of steam on cold glass

• NaCl dissolving in water

Which of these reactions shows a DECREASE in entropy?

• CaCO₃(s) → CaO(s) + CO₂(g)

• 3O₂(g) → 2O₃(g)

• 2NH₃(g) → 3H₂(g) + N₂(g)

• C₆H₆(l) → C₆H₆(g)

Tags

NGSS.HS-PS3-4

Which reaction has a +ΔS ?

• AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)

• H₂O(g) + CO₂(g) → H₂CO₃(aq)

• H₂(g) + I₂(g) → 2Hl(g)

• C₂H₂O₂(g) → 2CO(g) + H₂(g)

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

What is a spontaneous process ?

• slow process

• fast process

• process that needs an external intervention to occur

• process that does not need external intervention to occur / keep happening

Tags

NGSS.HS-PS3-4

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.

Tags

NGSS.HS-PS3-1

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

• A high negative enthalpy.

• A low negative enthalpy.

• A high positive enthalpy.

• A low positive enthalpy.

Tags

NGSS.HS-PS1-4

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.

Your enthalpy is +20 and your entropy is +5. Which temperature will give a spontaneous reaction?

• 0

• 4

• 8

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-5

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

Tags

NGSS.HS-PS1-5