CHE 221 Entropy online quiz

According to the Second Law of Thermodynamics, for any spontaneous process in an isolated system, the entropy:

• A) Decreases

• B) Remains constant

• C) Increases

• D) Becomes zero

Which of the following represents a system with higher entropy?

• A) Ice cube

• B) Water at 25°C

• C) Steam at 100°C

• D) Diamond

When a gas expands isothermally and reversibly, what happens to the entropy of the system?

• A) Decreases

• B) Remains the same

• C) Increases

• D) Becomes negative

In which of the following phase transitions is entropy expected to decrease?

• A) Vapor to liquid

• B) Solid to liquid

• C) Solid to gas

• D) Ice melting

A spontaneous process in an open system at constant temperature and pressure is characterized by:

• A) ΔS universe < 0

• B) ΔG < 0

• C) ΔH > 0

• D) ΔS system > 0

A sample of 1.00 mol of an ideal gas expands isothermally and reversibly from an initial volume of 5.00 L to 15.00 Lat a constant temperature of 300 K.

Calculate the entropy change of the gas during this process.

• A) 5.76 J/mol·K

• B) 8.31 J/mol·K

• C) 9.13 J/mol·K

• D) 10.22 J/mol·K

For a certain ideal gas Cp=5/2R cal/mol-ºC. Calculate the change in entropy suffered by 3 moles of the gas on being heated from 300 to 600ºK at (a) Constant pressure (b) Constant volume

• A) (a) 8.20 cal/K (b) 5.00 cal/K

• B) (a) 10.33 cal/K (b) 6.20 cal/K

• C) (a) 12.00 cal/K (b) 7.50 cal/K

• D) (a) 9.10 cal/K (b) 5.80 cal/K

Calculate the entropy change ΔSΔS in J/mol·K for 1.00 mol of butane gas when it is heated from 300 K to 600 K at constant pressure, using the polynomial heat capacity equation in your handbook:
Cp∘​=C1​+(C2*T)+(C3​*T^2)+(C4​*T^3)+(C5​*T^4)

• A) 28.75 J/mol·K

• B) 31.20 J/mol·K

• C) 34.50 J/mol·K

• D) 39.80 J/mol·K