Physical Chemistry - Thermodynamics
Q. In which of the following processes is the enthalpy change (ΔH) equal to the heat absorbed at constant pressure? (2019)
-
A.
Isothermal process
-
B.
Isochoric process
-
C.
Isobaric process
-
D.
Adiabatic process
Solution
In an isobaric process, the enthalpy change (ΔH) is equal to the heat absorbed or released at constant pressure.
Correct Answer: C — Isobaric process
Learn More →
Q. The heat capacity at constant volume (Cv) is defined as: (2022)
-
A.
The amount of heat required to raise the temperature of a substance by 1°C at constant pressure.
-
B.
The amount of heat required to raise the temperature of a substance by 1°C at constant volume.
-
C.
The total heat content of a substance.
-
D.
The heat required to change the phase of a substance.
Solution
The heat capacity at constant volume (Cv) is defined as the amount of heat required to raise the temperature of a substance by 1°C at constant volume.
Correct Answer: B — The amount of heat required to raise the temperature of a substance by 1°C at constant volume.
Learn More →
Q. What is the change in internal energy (ΔU) for an ideal gas during an isothermal process? (2021)
-
A.
ΔU = 0
-
B.
ΔU = nRT
-
C.
ΔU = -nRT
-
D.
ΔU = PV
Solution
In an isothermal process for an ideal gas, the temperature remains constant, which means the internal energy does not change. Therefore, ΔU = 0.
Correct Answer: A — ΔU = 0
Learn More →
Q. What is the standard enthalpy change (ΔH°) for the formation of water from its elements? (2022)
-
A.
-285.83 kJ/mol
-
B.
0 kJ/mol
-
C.
285.83 kJ/mol
-
D.
-241.82 kJ/mol
Solution
The standard enthalpy change for the formation of water from its elements (H2 and O2) is -285.83 kJ/mol.
Correct Answer: A — -285.83 kJ/mol
Learn More →
Showing 1 to 4 of 4 (1 Pages)
