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 4 of 30
- A. H = E - PV
- B. H = F - TS
- C. H - E = PV
- D. None of these
Explanation: Enthalpy is defined as H = E + PV, where E is internal energy. Rearranging gives H - E = PV, which matches option C.
Correct answer: H - E = PV- A. ∞
- B. 1
- C. -ve
- D. 0
Explanation: At the inversion point, the Joule-Thomson coefficient changes sign, so its value is zero.
Correct answer: 0- A. Two
- B. One
- C. Zero
- D. Three
Explanation: For a one-component, two-phase system, Gibbs phase rule gives F = 1 - 2 + 2 = 1.
Correct answer: One- A. Calorific value
- B. Heat of reaction
- C. Heat of combustion
- D. Heat of formation
Explanation: Burning one mole of a compound completely in oxygen defines its heat of combustion, usually expressed as the enthalpy of combustion at…
Correct answer: Heat of combustion- A. Negative
- B. Unity
- C. Infinity
- D. Zero
Explanation: For an ideal gas, the activity coefficient is unity, so ln y = ln 1 = 0. A nonzero value indicates deviation from ideal behaviour.
Correct answer: Zero- A. 0
- B. 2
- C. 1
- D. 3
Explanation: A binary vapour-liquid system ordinarily has two degrees of freedom under the phase rule, but the azeotropic condition imposes one…
Correct answer: 1- A. Positive
- B. Zero
- C. Negative
- D. None of these
Explanation: A perfect gas has enthalpy independent of pressure, so its Joule-Thomson coefficient, μJT = (∂T/∂P)H, is zero.
Correct answer: Zero- A. Remain unchanged
- B. Decrease
- C. Increase
- D. First fall and then rise
Explanation: A thermos flask greatly limits heat transfer, so the shaking work is dissipated internally as thermal energy and the tea temperature…
Correct answer: Increase- A. Boiling
- B. Triple
- C. Freezing
- D. Critical
Explanation: At the critical point, the liquid and vapour become indistinguishable and their properties merge.
Correct answer: Critical- A. Both A. & B.
- B. Volume
- C. Enthalpy
- D. Neither A nor B
Explanation: For an ideal solution, unlike-molecule interactions are effectively balanced by like-molecule interactions, giving zero enthalpy and zero…
Correct answer: Both A. & B.- A. Enthalpy
- B. Entropy
- C. Pressure
- D. None of these
Explanation: An isentropic process has constant entropy, so the entropy change is zero. Constant enthalpy describes throttling, not isentropic flow.
Correct answer: Entropy- A. Accomplishes only space heating in winter
- B. Accomplishes only space cooling in summer
- C. Works on Carnot cycle
- D. Accomplishes both A. and B
Explanation: A heat pump can operate reversibly in either direction, providing heating in winter and cooling in summer.
Correct answer: Accomplishes both A. and B- A. Both B. and C
- B. Single phase fluid of constant composition
- C. Open as well as closed systems
- D. Single phase fluid of varying composition
Explanation: The relation dE = Tds - PdV is the fundamental property relation for a single-phase, constant-composition simple compressible system.
Correct answer: Both B. and C- A. Entropy
- B. Enthalpy
- C. Pressure
- D. None of these
Explanation: A throttling valve has no shaft work and normally negligible heat transfer and changes in kinetic or potential energy, so the steady-flow…
Correct answer: Enthalpy- A. TR/(T2 - TR) × (T1 - T2)/T1
- B. TR/(T2 - TR) × T1/(T1 - T2)
- C. TR/(T1 - TR) × (T1 - T2)/T1
- D. None of these
Explanation: The ideal absorption refrigerator combines the refrigerator factor TR/(T2 - TR) with the heat-engine factor (T1 - T2)/T1.
Correct answer: TR/(T2 - TR) × (T1 - T2)/T1- A. 2
- B. 0
- C. 1
- D. 3
Explanation: Gibbs phase rule gives F = C - P + 2 = 3 - 3 + 2 = 2. Therefore, two intensive variables can be independently specified while maintaining…
Correct answer: 2- A. temperature and pressure
- B. States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant
- C. Applies only to binary systems
- D. Finds no application in gas-liquid equilibria involved in distillation
- E. None of these
Explanation: At constant temperature and pressure, the Gibbs-Duhem relation reduces to Σni dμi = 0.
Correct answer: States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant- A. Molar concentration
- B. Quantity (i.e. number of moles)
- C. Both A. and B
- D. Neither A. nor B
Explanation: For ideal mixing, ΔSmix = -RΣni ln xi, so the entropy change depends on both the component amounts and their mole fractions or…
Correct answer: Both A. and B- A. Indeterminate
- B. Positive
- C. Negative
- D. Zero
Explanation: At equilibrium, the system is at a minimum of Gibbs free energy under constant temperature and pressure, so the driving force for change…
Correct answer: Zero- A. Mass
- B. Temperature
- C. Specific volume
- D. Pressure
Explanation: Extensive properties scale with the amount of matter present, so doubling the mass doubles properties such as volume and total energy.
Correct answer: Mass