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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- A. Low temperature
- B. Both A. and B
- C. High pressure
- D. Neither A. nor B
Explanation: The forward reaction is exothermic, so lowering temperature favours SO3 formation.
Correct answer: Both A. and B- A. Extensive property
- B. Intensive property
- C. Force which drives the chemical system to equilibrium
- D. Both B. and C
Explanation: Chemical potential is an intensive property because it does not depend on the amount of substance.
Correct answer: Both B. and C- A. None of these
- B. Point
- C. State
- D. Path
Explanation: Heat and work depend on the path followed between two states, not only on the initial and final states, so they are path functions.
Correct answer: Path- A. co-efficient of thermal expansion
- B. Specific heat at constant pressure (Cp)
- C. Joule-Thomson co-efficient
- D. Specific heat at constant volume (CV)
Explanation: The volumetric coefficient of thermal expansion is defined as α = (1/V)(∂V/∂T)P.
Correct answer: co-efficient of thermal expansion- A. Same COP
- B. Increased COP
- C. Decreased COP
- D. Increased or decreased COP; depending upon the type of refrigerant
Explanation: For fixed evaporator temperature, lowering condenser temperature reduces the compressor pressure ratio and compressor work while…
Correct answer: Increased COP- A. 0.25
- B. 0.5
- C. 0.75
- D. 1
Explanation: For an ideal gas undergoing an isothermal process, PV is constant, so V2/V1 = P1/P2 = 1/1.005 ≈ 0.995.
Correct answer: 0.587. COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about____________________?
- A. 0.5
- B. 3.5
- C. 4.5
- D. 8.5
Explanation: One ton of refrigeration provides about 3.517 kW of cooling. With 1 kW of power input, COP = 3.517/1 ≈ 3.5.
Correct answer: 3.5- A. J/s
- B. J.S
- C. J/kmol
- D. kmol/J
Explanation: From E = hν, h has units of energy divided by frequency. Since frequency has units s⁻¹, the unit of Planck’s constant is J·s.
Correct answer: J.S- A. 1.987 cal/gm mole °K
- B. 1.987 BTU/lb. mole °R
- C. Both A. and B
- D. Neither A. nor B
Explanation: The universal gas constant is 1.987 cal/(g mol·K) and approximately 1.987 BTU/(lb mol·°R), so both listed values represent the same…
Correct answer: Both A. and B- A. More in liquid phase
- B. Zero in both the phases
- C. More in vapour phase
- D. Same in both the phases
Explanation: Phase equilibrium requires equality of the chemical potential of every component in the coexisting phases; otherwise, matter would…
Correct answer: Same in both the phases- A. SO2
- B. C2H4Cl2
- C. CCl2F2
- D. NH3
Explanation: Sulfur dioxide, ammonia, and dichlorodifluoromethane are established refrigerants, whereas C2H4Cl2, commonly dichloroethane, is not…
Correct answer: C2H4Cl2- A. Two liquids are completely separated into two layers
- B. Mutual solubility of the two liquids shows a decreasing trend
- C. A homogeneous solution (say of phenol water) is formed
- D. None of these
Explanation: At the upper critical solution temperature, the two partially miscible liquids become completely miscible and form one homogeneous phase.
Correct answer: A homogeneous solution (say of phenol water) is formed93. Maxwell's relation corresponding to the identity, dH = dS = Vdp + Σμi dni is_____________________?
- A. (∂T/∂V)S, ni = -(∂P/∂S)V, ni
- B. (∂S/∂P)T, ni = (∂V/∂T)P, ni
- C. (∂S/∂V)T, ni = (∂P/∂T)V, ni
- D. (∂T/∂P)S, ni = (∂V/∂S)P, ni
Explanation: For enthalpy expressed as H(S,P,n), its differential contains T dS + V dP, so equality of mixed partial derivatives gives (∂T/∂P)S,n =…
Correct answer: (∂T/∂P)S, ni = (∂V/∂S)P, ni- A. Temperature
- B. Pressure
- C. Volume
- D. None of these
Explanation: Isopiestic means constant pressure, just as isothermal means constant temperature and isochoric means constant volume.
Correct answer: Pressure- A. 2
- B. 0
- C. 3
- D. 1
Explanation: There are two components, water and nitrogen, and two phases, liquid and vapour; the phase rule gives F = C − P + 2 = 2 − 2 + 2 = 2.
Correct answer: 2- A. Bertholet equation
- B. None of these
- C. Beattie-Bridgeman equation
- D. Clausius-Clapeyron equation
Explanation: The Bertholet and Beattie-Bridgeman equations relate pressure, volume, and temperature and are equations of state.
Correct answer: Clausius-Clapeyron equation- A. Increases
- B. Decreases
- C. Remains unchanged
- D. Decreases linearly
Explanation: For melting, dT/dP = ΔV/ΔS; because paraffin contracts on solidification, melting involves an increase in volume, while ΔS of melting is…
Correct answer: Increases- A. Cp < Cv
- B. Cp = Cv
- C. Cp > Cv
- D. C ≥ Cv
Explanation: An ideal-gas adiabat follows PV^γ = constant, whereas an isotherm follows PV = constant.
Correct answer: Cp = Cv- A. Adiabatic
- B. Isothermal
- C. Isobaric
- D. Isometric
Explanation: For an ideal gas, internal energy depends only on temperature. A reversible isothermal process keeps temperature constant, so the internal…
Correct answer: Isothermal- A. Boiling point of liquids
- B. Melting point of wax
- C. Melting point of ice
- D. None of these
Explanation: Ice is unusual because its melting curve has a negative slope, so increasing pressure lowers its melting point.
Correct answer: Melting point of ice