Free Chemical Engineering Thermodynamics MCQs with Answers
598 Chemical Engineering Thermodynamics MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Last updated
598 questions · page 26 of 30
- A. J/kg°K
- B. W/m2°C
- C. W/m°K
- D. J/m3°K
Explanation: Specific heat is energy required per unit mass per unit temperature rise.
Correct answer: J/kg°K- A. Inversely
- B. Linearly
- C. Exponentially
- D. Negligibly
Explanation: Raoult's law gives the total pressure as the sum of each component's partial pressure, with each partial pressure proportional to its mole…
Correct answer: Linearly- A. Kistyakowsky equation
- B. Kopp's rule
- C. Antoine equation
- D. Trouton's rule
Explanation: The Antoine equation correlates vapour pressure with temperature, commonly written as log₁₀P = A − B/(T + C).
Correct answer: Antoine equation- A. 1
- B. 2.42
- C. 1.987
- D. 4.97
Explanation: Including the Fahrenheit-to-Celsius interval conversion, 1 Btu/(lb·°F) equals approximately 4.187 kJ/(kg·K).
Correct answer: 1- A. Heat of vaporisation
- B. Both B. and C.
- C. Heat of fusion
- D. Melting point
Explanation: The melting point and heat of fusion are comparatively insensitive to pressure, whereas the heat of vaporisation changes appreciably with…
Correct answer: Both B. and C.- A. Vapor follows ideal gas law
- B. Volume in the liquid state is negligible
- C. Both A. & B.
- D. Neither A. nor B.
Explanation: The commonly used integrated Clausius-Clapeyron form assumes an ideal-gas vapour and neglects the liquid molar volume relative to the…
Correct answer: Both A. & B.- A. Superheated
- B. Supersaturated
- C. Saturated
- D. None of these
Explanation: When a vapour's partial pressure is below its equilibrium vapour pressure at the same temperature, it is unsaturated and is termed…
Correct answer: Superheated- A. 40.5
- B. 34.4
- C. 26.8
- D. 25
Explanation: The stirring work is 40 × 9.8 × 4 × 500 = 784 kJ, which raises 20 kg of water by about 784/(20 × 4.18) = 9.4°C.
Correct answer: 34.4- A. (COP)R = (COP)HP = 0.6
- B. (COP)R = 2.5; (COP)HP = 1.5
- C. (COP)R = 1.5; (COP)HP = 2.5
- D. (COP)R = (COP)HP = 2.5
Explanation: For a reversible engine, η = 1 − T_L/T_H = 0.4, so T_L/T_H = 0.6. Therefore, (COP)R = 0.6/0.4 = 1.5 and (COP)HP = (COP)R + 1 = 2.5.
Correct answer: (COP)R = 1.5; (COP)HP = 2.5- A. More
- B. Less
- C. Same
- D. More or less; depends on the nature of solution
Explanation: A super-cooled solution is metastable, so its Gibbs free energy is higher than that of the solid phase.
Correct answer: More- A. Positive
- B. Negative
- C. No
- D. None of these
Explanation: Negative deviation from Raoult’s law lowers the total vapour pressure, so the mixture boils at a temperature higher than either pure…
Correct answer: Negative- A. No
- B. Negative
- C. Positive
- D. None of these
Explanation: Positive deviation raises the total vapour pressure above Raoult's-law prediction, so the mixture boils at a lower temperature than either…
Correct answer: Positive- A. Total pressure of the system
- B. Volume of the reactor
- C. Initial concentration of N2 and H2
- D. Temperature
Explanation: For a specified reaction and standard state, the equilibrium constant is a function of temperature, as expressed through the van’t Hoff…
Correct answer: Temperature- A. K3 = K1.K2
- B. K3 = (K1.K2)0.5
- C. K3(K1+K2)/2
- D. K3 = (K1.K2)2
Explanation: Adding reactions adds their standard Gibbs-energy changes, while equilibrium constants multiply.
Correct answer: K3 = K1.K2- A. k cal
- B. °K
- C. k cal/°K
- D. k cal. °K
Explanation: In the Arrhenius relation, the slope is −E/R. Since E has energy per mole and R has energy per mole-kelvin, their ratio has units of kelvin.
Correct answer: °K- A. 2HI ⇌ H2 + I2
- B. N2 + O2 ⇌ 2NO
- C. N2O2 ⇌ 2NO2
- D. None of these
Explanation: Lower pressure favours the side with more gas molecules. In N₂O₂ ⇌ 2NO₂, the number of gas moles increases from one to two, whereas…
Correct answer: N2O2 ⇌ 2NO2- A. (i) increases (ii) decreases
- B. (i) decreases (ii) decreases
- C. (i) increases (ii) increases
- D. (i) decreases (ii) increases
Explanation: Oxidation of SO2 to SO3 is exothermic, so increasing temperature lowers the equilibrium conversion.
Correct answer: (i) decreases (ii) increases- A. Increases
- B. Decreases
- C. Remains unchanged
- D. Unpredictable from the data
Explanation: Ammonia synthesis reduces the total gas moles from four to two, so increasing pressure shifts equilibrium toward ammonia.
Correct answer: Increases- A. ln (k2/k1) = (E/R) (1/T2 - 1/T1)
- B. ln (k2/k1) = (E/R) (1/T1 - 1/T2)
- C. exp (k2/k1) = (E/R) (1/T2 - 1/T1)
- D. exp (k2/k1) = (E/R) (1/T1 - 1/T2)
Explanation: Integrating the Arrhenius equation between two temperatures gives ln(k2/k1) = (E/R)(1/T1 − 1/T2).
Correct answer: ln (k2/k1) = (E/R) (1/T1 - 1/T2)- A. Not feasible
- B. Just feasible
- C. Very much feasible
- D. Unpredictable as ΔG is no measure of feasibility of a reaction
Explanation: A large negative ΔG indicates a strongly thermodynamically spontaneous or feasible forward reaction under the specified conditions.
Correct answer: Very much feasible