Chemical Engineering Thermodynamics MCQ Questions & Answers

Chemical Engineering Thermodynamics MCQ Questions & Answers | Chemical Engineering

Learn Chemical Engineering Thermodynamics MCQ questions & answers are available for a Chemical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. Chemical Engineering Thermodynamics MCQ question is the important chapter for a Chemical Engineering and GATE students. Page-3 section-6

At constant temperature and pressure, for one mole of a pure substance, the ratio of the free energy to the chemical potential is

A) Zero B) One C) Infinity D) Negative

Discuss

Answer & Solution

Answer: Option B

Solution:

For one mole of a pure substance free energy is identical with chemical potential constant temperature and pressure.

Clayperon equation deals with the

A) Rate of change of vapour pressure with temperature B) Effect of an inert gas on vapour pressure C) Calculation of ΔF for spontaneous phase change D) Temperature dependence of heat of phase transition

Discuss

Answer & Solution

Answer: Option A

Solution:

$$\frac{{{\bf{dp}}}}{{{\bf{dT}}}}{\bf{ = }}\frac{{\bf{L}}}{{\left( {{\bf{T}}\left( {{{\bf{V}}_{\bf{v}}}{\bf{ - }}{{\bf{V}}_{\bf{l}}}} \right)} \right)}}$$ This is the Clausius-Clapeyron equation.
From the equation we can say that equation deals with change of pressure on change of temperature.

Pick out the wrong statement:

A) The expansion of a gas in vacuum is an irreversible process B) An isometric process is a constant pressure process C) Entropy change for a reversible adiabatic process is zero D) Free energy change for a spontaneous process is negative

Discuss

Answer & Solution

Answer: Option B

Solution:

Isometric process means constant-volume or isochoric process.

Degree of freedom of the system ice-water-vapour will be

A) 0 B) 1 C) 2 D) 3

Discuss

Answer & Solution

Answer: Option A

Solution:

The given number of component $$ = 1$$
Given number of phases $$= 3$$ (ice-water-vapour)
We know,
degree of freedom (number of independent variable) $$ = C - \theta + 2.$$
$$ \Rightarrow f = 1 - 3 + 2 = 0.$$

Absolute zero temperature signifies the

A) Minimum temperature attainable B) Temperature of the heat reservoir to which a Carnot engine rejects all the heat that is taken in C) Temperature of the heat reservoir to which a Carnot engine rejects no heat D) None of these

Discuss

Answer & Solution

Answer: Option C

Solution:

The correct answer is Option C: Temperature of the heat reservoir to which a Carnot engine rejects no heat.
Here's why:
Absolute zero is the lowest possible temperature, theoretically 0 Kelvin or -273.15 degrees Celsius.
It's important to understand how Carnot engines relate to temperature and heat rejection.
A Carnot engine is a theoretical engine that operates with the highest possible efficiency between two heat reservoirs (a hot one and a cold one).
Option A is partially correct. Absolute zero is the minimum temperature, but the options relates to engines making option C more relevant.
Option B states the carnot engine rejects *all* the heat. It could only do that at 0 kelvin.
The key is that a Carnot engine's efficiency depends on the temperature difference between the hot and cold reservoirs.
At absolute zero (0 Kelvin), the cold reservoir has no more energy to give, so the Carnot engine cannot reject any heat to it. This means the engine could theoretically convert all the heat from the hot reservoir into work.
Therefore, absolute zero signifies the temperature at which a Carnot engine rejects no heat.