Entropy Knowledge-Based Download PDF

Questions

1. 1.

   According to the second law of thermodynamics, which of the following statements must be true for any spontaneous process?

   • A) The entropy of the system must increase ($\Delta S_{\text{sys}} > 0$).
   • B) The entropy of the surroundings must increase ($\Delta S_{\text{surr}} > 0$).
   • C) The enthalpy of the system must decrease ($\Delta H_{\text{sys}} < 0$).
   • D) The total entropy of the universe must increase ($\Delta S_{\text{univ}} > 0$).
2. 2.

   According to the Boltzmann formula for entropy, $S = k_{\text{B}} \ln W$, what does the term $W$ represent?

   • A) The number of accessible microscopic configurations corresponding to a macroscopic state
   • B) The total mechanical work performed by or on the system during a reversible process
   • C) The rate of thermal energy transfer per unit area across the system boundary
   • D) The average molecular weight and vibrational frequency of the constituent particles
3. 3.

   Which of the following statements correctly explains why heating an ideal gas at constant volume leads to an increase in its entropy?

   • A) Heating increases the total number of gas molecules, which expands the spatial boundaries occupied by the system.
   • B) Heating increases the average kinetic energy and broadens the distribution of accessible molecular energy states, thereby increasing the number of microstates.
   • C) Heating reduces intermolecular forces, forcing the gas molecules to adopt a rigid, uniform spatial arrangement.
   • D) Heating decreases the rate of molecular collisions, allowing the system to achieve a lower state of energy dispersal.
4. 4.

   Which of the following substances has the highest standard molar entropy ($S^\circ$) at 298 K and 1 bar?

   • A) $C_3H_8(g)$
   • B) $CH_4(g)$
   • C) $H_2O(l)$
   • D) $C(s)$
5. 5.

   Which of the following processes is accompanied by a decrease in entropy ($\Delta S < 0$)?

   • A) $2\text{SO}_2(g) + \text{O}_2(g) \rightarrow 2\text{SO}_3(g)$
   • B) $\text{CaCO}_3(s) \rightarrow \text{CaO}(s) + \text{CO}_2(g)$
   • C) $\text{H}_2\text{O}(s) \rightarrow \text{H}_2\text{O}(l)$
   • D) $\text{NH}_4\text{NO}_3(s) \rightarrow \text{NH}_4^+(aq) + \text{NO}_3^-(aq)$