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. R
- B. > R
- C. < R
- D. 0.5 R
Explanation: For a van der Waals gas, the attractive-force term makes the denominator in the real-gas expression for Cp − Cv less than one, so Cp − Cv…
Correct answer: > R- A. Varies linearly
- B. Decreases
- C. Increases
- D. Does not vary
Explanation: For most gases, molecular rotational and vibrational contributions become more significant as temperature rises, so the molal heat…
Correct answer: Increases- A. 0.5
- B. 1
- C. 1.5
- D. 2
Explanation: Using π = CRT, the concentration is 1/22.4 mol/L and RT at 0°C is approximately 22.4 L·atm/mol.
Correct answer: 1- A. Liquid
- B. Solid
- C. Gaseous
- D. None of these
Explanation: For most substances, the liquid phase has a larger heat capacity than the solid phase because molecules in the liquid can access more…
Correct answer: Liquid- A. 0.4
- B. 0.6
- C. 0.8
- D. 0.2
Explanation: For an ideal liquid mixture, the vapor contribution is proportional to x_iP_i^sat.
Correct answer: 0.626. Molar heat capacity of water in equilibrium with ice at constant pressure is_____________________?
- A. 0
- B. 1
- C. ∞
- D. None of these
Explanation: During melting or freezing at constant pressure, heat can be added or removed as latent heat while the temperature remains constant.
Correct answer: ∞- A. Increase
- B. None of these
- C. Remain unchanged
- D. Decrease
Explanation: Adding solute usually replaces some water, whose specific heat is relatively high, with solute having a different and generally lower heat…
Correct answer: Decrease- A. 0.1013
- B. 1.013
- C. 10.13
- D. 101.3
Explanation: At 100°C, water boils at approximately 1 atm, and 1 atm equals 1.013 bar. The larger values are incorrect unit or decimal-place conversions.
Correct answer: 1.013- A. Decreases with increased temperature
- B. All A., B. & C.
- C. Becomes zero at the critical point
- D. Decreases as pressure increases
Explanation: Latent heat of vaporisation decreases as temperature and pressure rise, because the liquid and vapour become more alike.
Correct answer: All A., B. & C.- A. Measures the elevation in boiling point
- B. Is not dependent on the temperature
- C. Measures the depression in freezing point
- D. Is a function of the liquid phase composition
Explanation: The activity coefficient measures how a liquid component departs from ideal-solution behaviour and generally varies with liquid…
Correct answer: Is a function of the liquid phase composition- A. pOH and pH both decreases
- B. pOH decreases and pH increases
- C. pH and pOH both increases
- D. pH decreases and pOH increases
Explanation: For pure water, increasing temperature increases the ionisation constant, so the concentrations of H+ and OH− both increase equally.
Correct answer: pOH and pH both decreases32. Boiling point of a solution as compared to that of the corresponding solvent is _________________?
- A. Less
- B. More
- C. Same
- D. Either more or less; depends upon the solvent
Explanation: A dissolved non-volatile solute lowers the solvent vapour pressure, so a higher temperature is needed for the solution to boil.
Correct answer: More- A. Normality
- B. Molarity
- C. Molality
- D. Formality
Explanation: Molality is defined as gram-moles of solute per kilogram of solvent. Unlike molarity, it uses the mass of solvent rather than the volume…
Correct answer: Molality- A. 1
- B. 2
- C. 3
- D. 4
Explanation: Using the ideal-gas relation for density, ρ = PM/RT, with P = 2 atm, M = 44 kg/kmol, and T = 536 K gives approximately 2 kg/m3.
Correct answer: 2- A. Heat of mixing
- B. Heat of hydration
- C. Standard integral heat of solution
- D. Heat of solvation
Explanation: When both components are liquids, the enthalpy change on combining them is called the heat of mixing.
Correct answer: Heat of mixing- A. Increases
- B. Decreases
- C. Remains unchanged
- D. Either A. or B.; depends on the liquid
Explanation: For chemically similar liquids, increasing molecular weight generally strengthens intermolecular attraction and lowers volatility, so…
Correct answer: Decreases- A. Deviate from ideal gas behaviour to the same degree
- B. Have nearly the same compressibility factor
- C. Both A. and B.
- D. Neither A. nor B.
Explanation: The principle of corresponding states says that gases with equal reduced temperature and pressure have approximately the same…
Correct answer: Both A. and B.- A. No component is concentrated at the surface of the solution
- B. In the formation of solution, chemical combination/molecular association between unlike
- C. The component molecules are non polar and are of almost equal size
- D. molecules takes place
- E. The attractive forces between like and unlike molecules are almost equal
Explanation: Raoult's law works best when unlike molecules interact nearly as strongly as like molecules and no association or chemical reaction…
Correct answer: In the formation of solution, chemical combination/molecular association between unlike- A. Experimental data
- B. Phase rule
- C. Empirical equations
- D. Theoretical equations
Explanation: The phase rule determines the degrees of freedom and does not provide numerical equilibrium relations or phase compositions.
Correct answer: Phase rule- A. 46
- B. 92
- C. -23
- D. -92
Explanation: Using formation enthalpies, ΔH for decomposition is [0] − 2(−46) = +92 kJ per stoichiometric reaction as written.
Correct answer: 92