21. The work done by an ideal gas during an isothermal expansion is:
a) Zero
b) Positive
c) Negative
d) Infinite
Answer: a) Zero
22. The Maxwell-Boltzmann distribution describes the distribution of:
a) Energies of particles in a gas
b) Velocities of particles in a gas
c) Pressures of particles in a gas
d) Densities of particles in a gas
Answer: b) Velocities of particles in a gas
23. The efficiency of a Carnot engine operating between two temperatures, Th and Tc, is given by:
a) η = 1 – (Tc / Th)
b) η = 1 – (Th / Tc)
c) η = (Th – Tc) / Th
d) η = (Th – Tc) / Tc
Answer: a) η = 1 – (Tc / Th)
24. The specific heat capacity of water is approximately:
a) 1 J/g°C
b) 4 J/g°C
c) 10 J/g°C
d) 100 J/g°C
Answer: b) 4 J/g°C
25. The enthalpy change of a reaction can be calculated using:
a) ΔH = Q / T
b) ΔH = Q + T
c) ΔH = T / Q
d) ΔH = T – Q
Answer: a) ΔH = Q / T
