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. Isobaric
- B. None of these
- C. Isentropic
- D. Polytropic
Explanation: The Rankine cycle has two isentropic processes in the ideal case and two constant-pressure processes, not two isothermal processes.
Correct answer: None of these582. Thermodynamic cycle involved in the working of a thermal power plant is the ______________ cycle ?
- A. Joule
- B. Carnot
- C. Rankine
- D. Brayton
Explanation: A steam power plant uses the Rankine cycle, in which water is pumped, heated and vaporised in a boiler, expanded through a turbine, and…
Correct answer: Rankine- A. Enthalpy-pressure
- B. Temperature - pressure
- C. Enthalpy - entropy
- D. Temperature - entropy
Explanation: A temperature-entropy (T-S) diagram is the thermodynamic counterpart of a pressure-volume diagram: for a reversible process, the area…
Correct answer: Temperature - entropy- A. Quasi-static
- B. Adiabatic
- C. Isothermal
- D. Isentropic
Explanation: For a quasi-static process, pressure is defined at every intermediate state, so boundary work can be calculated as W = ∫p dv.
Correct answer: Quasi-static- A. t = 15 + 0.0065 h
- B. t = 15 - 0.0065 h
- C. t = 0.0035 h - 15
- D. t = 15 - 0.0035 h
Explanation: The standard tropospheric lapse rate is about 6.5°C per kilometre, so temperature falls by 0.0065°C per metre from the sea-level value of…
Correct answer: t = 15 - 0.0065 h- A. Exponentially
- B. Linearly
- C. Slowly first and then rapidly
- D. Rapidly first and then slowly
Explanation: For saturated steam, specific volume falls steeply as pressure first increases, then the rate of decrease becomes smaller over much of the…
Correct answer: Rapidly first and then slowly- A. CCl2F2
- B. CCl3F
- C. CClF3
- D. CCl4F
Explanation: Freon-12 is dichlorodifluoromethane, whose molecular formula is CCl2F2. The related formula CCl3F represents Freon-11, a common distractor.
Correct answer: CCl2F2- A. Enthalpy
- B. Pressure
- C. Entropy
- D. Volume
Explanation: Steam is superheated by adding heat after it has become dry saturated steam, normally at essentially constant boiler pressure.
Correct answer: Pressure- A. Indeterminate
- B. Infinity
- C. Zero
- D. Same as that at any other temperature
Explanation: At the critical temperature, the liquid and vapour phases become indistinguishable and the liquid-vapour interface disappears.
Correct answer: Zero- A. 8
- B. 35
- C. 65
- D. 80
Explanation: Typical internal-combustion engines convert roughly one-quarter to one-third of the fuel energy into useful work, so about 35% is the…
Correct answer: 35- A. 3
- B. 5
- C. 0.5
- D. 1.5
Explanation: For a Carnot refrigerator, COP equals Tₗ/(Tₕ−Tₗ), using absolute temperatures. Here Tₗ=250 K and Tₕ=300 K, giving COP=250/50=5.
Correct answer: 5- A. 0.8
- B. 1
- C. 1.4
- D. 1.8
Explanation: For air and many common gases below about 500°C, the heat-capacity ratio gamma = cp/cv is commonly approximated as 1.4.
Correct answer: 1.4- A. 0°K to 273°K
- B. 0°C to - 123°C
- C. 0°C to - 273°C
- D. 0°K to 123°K
Explanation: Cryogenics commonly deals with temperatures below about 123 K, extending toward absolute zero.
Correct answer: 0°K to 123°K- A. Base and strong acid
- B. Base and weak acid
- C. Acid and weak base
- D. None of these
Explanation: Dilute strong acid and strong base are both completely ionised, so their net ionic reaction is always H+ + OH− forming water and has…
Correct answer: Base and strong acid- A. Degradation of energy
- B. Decrease in system pressure
- C. Increase in the availability of energy
- D. Increase in the temperature
Explanation: Entropy measures the degradation or loss of the ability of energy to produce useful work.
Correct answer: Degradation of energy- A. 10 atm-1
- B. 10 (dimensionless)
- C. 105 atm-1
- D. 105 (dimensionless)
Explanation: For A + B ⇌ AB, Kp = pAB/(pA pB) = 1/[10⁻² × 10⁻³] = 10⁵ atm⁻¹. The dimensional form is expected here because the pressures are inserted…
Correct answer: 105 atm-1- A. 1.0
- B. 1.3
- C. 2.3
- D. 3.3
Explanation: For FeO + CO ⇌ Fe + CO₂, the equilibrium constant is K = pCO₂/pCO = 0.435 because the solids have unit activity.
Correct answer: 3.3- A. Superheated steam
- B. Saturated steam
- C. Wet steam
- D. Saturated water
Explanation: Superheated steam is at a temperature above its saturation temperature and contains less liquid-like character, so its properties approach…
Correct answer: Superheated steam