Enthalpy, Entropy, and Gibb's Free Energy Quiz

6.  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-PS3-1

At what temperature would a given reaction become spontaneous if ΔH =+119kJ and ΔS=+263J/K.mol

• 452 K

• 2210 K

• 382 K

• 363 K

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-PS3-1

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

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

Entropy is a measure of

• accuracy

• precision

• the disorder of a system

• the attraction of a nucleus for an electron

Tags

NGSS.HS-PS3-4

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)