Entropy and Thermodynamics Quiz

Which of the following processes results in an increase in entropy?

• Freezing of water

• Condensation of steam

• Dissolution of salt in water

• Compression of a gas

Consider the following reaction: N₂(g) + 3H₂(g) → 2NH₃(g) Where S°N₂ = 192 J/molK; S°H₂ = 131 J/molK; S°NH₃ = 193 J/molK What is the standard entropy change (S°) for this reaction?

• -199 J/molK

• -200 J/molK

• -192 J/molK

• 198 J/molK

Tags

NGSS.HS-PS3-1

For the reaction: 2NO(g) + O₂(g) → 2NO₂(g) Where H° = -114 kJ/mol and S° = -146 J/molK What is the Gibbs free energy (G°) at 298K?

• -70.5 kJ/mol

• -115.6 kJ/mol

• -89.5 kJ/mol

• -100.4 kJ/mol

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

The decomposition reaction of calcium carbonate is as follows: CaCO₃(s) → CaO(s) + CO₂(g) At 298 K, H° = 178 kJ/mol and S° = 160 J/molK At what temperature does the reaction become spontaneous?

• 1113K

• 1500K

• 298K

• 1000K

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

For which of the following reactions will S° be most positive?

• H₂ (g) + Cl₂ (g) → 2HCl (g)

• CaCO₃ (s) → CaO (s) + CO₂ (g)

• C₂H₆ (g) → C₂H₄ (g) + H₂ (g)

• 2SO₂ (g) + O₂ (g) → 2SO₃ (g)

Tags

NGSS.HS-PS3-4

Which of the following reactions would have the most negative H°?

• H₂ (g) + 1/2 O₂ (g) → H₂O (l)

• C₂H₆ (g) + 7/2 O₂ (g) → 2CO₂ (g) + 3H₂O (l)

• N₂ (g) + 3H₂ (g) → 2NH₃ (g)

• CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l)

Tags

NGSS.HS-PS1-4

Which reaction results in a decrease in entropy?

• 2NO₂ (g) → N₂O₄ (g)

• CaCO₃ (s) → CaO (s) + CO₂ (g)

• NH₄NO₃ (s) → NH₄ (aq) + NO₃ (aq)

• CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (g)

Which process is expected to increase the entropy of the system?

• Dissolution of NaCl (s) in water

• Crystallization of sugar from a solution

• Condensation of steam into liquid water

• Compression of an ideal gas

What is the oxidation number of chromium in the ionic compound ammonium dichromate, (NH₄)₂Cr₂O₇?

• +3

• +4

• +5

• +6

• +7

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Balance the following reaction. How many electrons are transferred?

• 3

• 4

• 6

• 8

• 2

Tags

NGSS.HS-PS1-7