Q1. Which thermodynamic quantity is a measure of disorder in a system?
A. Entropy
B. Enthalpy
C. Internal energy
D. Gibbs free energy
Q2. Which of the following processes has a negative \(\Delta S\)?
A. \(H_2O(s) \rightarrow H_2O(l)\)
B. \(H_2O(g) \rightarrow H_2O(l)\)
C. \(2H_2(g) + O_2(g) \rightarrow 2H_2O(g)\)
D. \(NH_4Cl(s) \rightarrow NH_3(g) + HCl(g)\)
Q3. For an ideal gas (\(\gamma = 1.4\)) expanding adiabatically from 15 L to 30 L at 450 K, what is the final temperature?
A. 225 K
B. 341 K
C. 595 K
D. 450 K
Q4. For the reaction \( 2A(g) + B(g) \rightarrow 2D(g) \), \( \Delta U = -10.5 \, \text{kJ} \), \( \Delta S = -44.1 \, \text{J/K} \) at 298 K. What is \( \Delta G \)?
A. -10.5 kJ
B. 10.5 kJ
C. 0.15 kJ
D. -0.15 kJ
Q5. For a process with \(\Delta H = 50 \, \text{kJ}\) and \(\Delta G = 20 \, \text{kJ}\) at 300 K, what is \(\Delta S\)?
A. 150 J/K
B. 50 J/K
C. -100 J/K
D. 100 J/K
Q6. What is the relationship between \(\Delta H\) and \(\Delta U\) for the reaction \(2SO_2(g) + O_2(g) \rightarrow 2SO_3(g)\) at 298 K? (\(R = 8.314 \, \text{J/mol·K}\))
A. \(\Delta H = \Delta U + 2.48 \, \text{kJ}\)
B. \(\Delta H = \Delta U - 2.48 \, \text{kJ}\)
C. \(\Delta H = \Delta U\)
D. \(\Delta H = \Delta U + 4.96 \, \text{kJ}\)
Q7. Using Hess’s law, calculate \(\Delta H\) for \(2S(s) + 3O_2(g) \rightarrow 2SO_3(g)\) given: \(S(s) + O_2(g) \rightarrow SO_2(g)\), \(\Delta H = -296.8 \, \text{kJ/mol}\); \(2SO_2(g) + O_2(g) \rightarrow 2SO_3(g)\), \(\Delta H = -197.8 \, \text{kJ/mol}\).
A. -494.6 kJ
B. 791.4 kJ
C. -791.4 kJ
D. -98.9 kJ
Q8. For a reaction with \(\Delta H = 120 \, \text{kJ/mol}\) and \(\Delta S = 300 \, \text{J/K}\), what is \(\Delta G\) at 400 K?
A. 120 kJ/mol
B. -120 kJ/mol
C. 300 kJ/mol
D. 0 kJ/mol
Q9. For an exothermic reaction at constant pressure, the heat evolved is equal to:
A. \(\Delta U\)
B. \(\Delta H\)
C. \(\Delta G\)
D. \(-\Delta U\)
Q10. The bond enthalpy of C-Cl in \( \ce{CCl4(g)} \) is to be calculated given: \( \Delta H_f^\circ(\ce{CCl4,g}) = -95.7 \, \text{kJ/mol} \), \( \Delta H_a(\ce{C,g}) = 715 \, \text{kJ/mol} \), \( \Delta H_a(\ce{Cl2,g}) = 242 \, \text{kJ/mol} \). What is the bond enthalpy?
A. 242.0 kJ/mol
B. 715.0 kJ/mol
C. 323.7 kJ/mol
D. 95.7 kJ/mol
Chemistry — Thermodynamics
Set 2 of 20
15:00
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