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.
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598 questions · page 24 of 30
- A. Is unity at all temperature
- B. Decreases with pressure rise
- C. Is unity at Boyle's temperature
- D. Zero
Explanation: An ideal gas obeys PV = nRT exactly, so its compressibility factor Z = PV/(nRT) is unity at every temperature and pressure.
Correct answer: Is unity at all temperature- A. Is saturated
- B. Shows positive deviation from Raoult's law
- C. Shows negative deviation from Raoult's law
- D. Is unsaturated
Explanation: Positive deviation from Raoult's law raises the total vapour pressure above the ideal value, so the liquid boils at a lower temperature…
Correct answer: Shows positive deviation from Raoult's law463. Specific gravity on API scale is given by the relation (where, G = specific gravity at 15.5°C) ?
- A. °API = 200(G - 1)
- B. °API = (140/G) - 130
- C. °API = (141.5/G) - 131.5
- D. °API = 145 - (145/G)
Explanation: The API gravity relation at 15.5°C (60°F) is °API = 141.5/G - 131.5, where G is the specific gravity.
Correct answer: °API = (141.5/G) - 131.5- A. All A., B. & C.
- B. Rotational
- C. Translational
- D. Vibrational
Explanation: Internal energy is the microscopic energy stored within a substance, including molecular translational, rotational, and vibrational…
Correct answer: All A., B. & C.- A. Exhibits negative deviation from Raoult's law
- B. Exhibits positive deviation from Raoult's law
- C. Obeys Raoult's law
- D. May exhibit either positive or negative deviation from Raoult's law
Explanation: In a binary solution, positive deviation means unlike A-B interactions are weaker than the average like interactions, increasing the…
Correct answer: Exhibits positive deviation from Raoult's law- A. 756.2
- B. 780.5
- C. 801.5
- D. 880.5
Explanation: Using Raoult’s law, P = ΣxiPi, with total amount 1.12 kg mol gives mole fractions 0.4018, 0.3929 and 0.2054.
Correct answer: 801.5- A. Humidity
- B. Molecular weight
- C. Compressibility
- D. None of these
Explanation: The corresponding-states principle states that fluids at equal reduced temperature and pressure have approximately equal compressibility…
Correct answer: Compressibility- A. Activation energy
- B. Heat capacities of gases
- C. Molal heat capacities of gases
- D. Heat capacities of solids
Explanation: Kopp’s rule estimates the molar heat capacity of a solid compound by adding the heat-capacity contributions of its constituent atoms.
Correct answer: Heat capacities of solids- A. loge (p/p0) = (λ/R) (1/T0 - 1/T)
- B. (P + a/V2)(V-b) = RT
- C. PV = RT + B/V + y/V2 + ....
- D. p = [RT/(V - b)] - (a/TV2)
Explanation: The virial equation and van der Waals-type equations relate pressure, volume and temperature, so they are equations of state.
Correct answer: loge (p/p0) = (λ/R) (1/T0 - 1/T)- A. 40732
- B. 2676
- C. 2263
- D. 540
Explanation: At about 98°C, the latent heat of vaporisation of water is approximately 2.26 × 10³ kJ/kg.
Correct answer: 2263- A. Clapeyron's equation
- B. Gibb's equation
- C. Trouton's rule
- D. Kopp's rule
Explanation: Kopp's rule estimates the molar heat capacity of a solid compound by adding the atomic heat capacities of its constituent elements.
Correct answer: Kopp's rule- A. Both B. and C.
- B. ΔH = 0
- C. ΔV = 0
- D. ΔH = 1 (+ ve) and Δ V = -ve
Explanation: An ideal solution has zero enthalpy and zero volume change on mixing because intermolecular interactions are effectively unchanged.
Correct answer: Both B. and C.- A. Solution
- B. Formation
- C. Combustion
- D. Fusion
Explanation: The reaction forms one mole of liquid carbon disulfide directly from its constituent elements in their elemental forms, so its heat change…
Correct answer: Formation- A. Saturated
- B. Molar
- C. None of these
- D. Normal
Explanation: Raoult's law is characteristic of an ideal solution, but ideal solution is not among the listed choices.
Correct answer: None of these- A. 15
- B. 30
- C. 85
- D. 170
Explanation: The first reaction gives ΔG°f(NO₂) = 100/2 = 50 kJ/mol. From NO + ½O₂ → NO₂, −35 = 50 − ΔG°f(NO), so ΔG°f(NO) = 85 kJ/mol.
Correct answer: 85- A. Heat capacity
- B. Thermal conductivity
- C. Viscosity
- D. Surface tension
Explanation: Kopp's rule estimates the molar heat capacity of a compound by adding the atomic heat-capacity contributions of its constituent elements.
Correct answer: Heat capacity- A. High pressure & high temperature
- B. High pressure & low temperature
- C. Low pressure & high temperature
- D. Low pressure & low temperature
Explanation: At low pressure, molecules are far apart and intermolecular forces contribute little to the behaviour; high temperature also reduces the…
Correct answer: Low pressure & high temperature- A. 3R
- B. R/2
- C. 2R
- D. R
Explanation: For an ideal gas, the enthalpy relation gives Cp − Cv = R, where R is the gas constant on a consistent mass or molar basis.
Correct answer: R- A. 0.2
- B. 0.1
- C. 0.4
- D. 0.6
Explanation: Raoult’s law gives the pressure lowering as Δp = xsolute P°; therefore, doubling the lowering from 10 to 20 mm Hg doubles the solute mole…
Correct answer: 0.6- A. Decreases
- B. Increases
- C. Remains unchanged
- D. Increases linearly
Explanation: For most gases, vibrational and other molecular energy modes become increasingly active as temperature rises, so their molal heat…
Correct answer: Increases