Chemical Engineering Thermodynamics MCQ Questions & Answers | Chemical Engineering

Insulated cylinder $$ \Rightarrow $$   adiabatic system
$$\eqalign{ & \Rightarrow P{V^\gamma } = {\text{CONSTANT}} \cr & \Rightarrow T{V^{\gamma - 1}} = {\text{CONSTANT}} \cr & \Rightarrow \frac{{{T_1}}}{{{T_2}}} = \frac{{{V_2}^{\gamma - 1}}}{{{V_1}}} \cr & \Rightarrow \frac{{500}}{{{T_2}}} = {\left( 5 \right)^{\gamma - 1}} \cr & {C_P} - {C_V} = R\left( {{\text{For ideal gas}}} \right) \cr & \Rightarrow \gamma = 1.65 \cr & {\text{So, }}{T_2} = 176.05\,K \cr} $$

According to Le Chatelier's principle the system will react in such a way that it minimizes the effect of deviation from equilibrium. Since, ice has the more volume than water equilibrium shifts towards water (less volume) side thereby, minimizing the effect of pressure and regaining a new equilibrium.

Hess law : if different process are used to bring the same chemical reaction than the enthalpy change is same for all of them.
(Note : enthalpy is a point function doesn’t depends on the path between.)

It is the point where the air becomes saturated and gives its first liquid bubble of more volatile substance in an solution this point corresponding temperature and pressure is called dew temperature and dew pressure.

The First Law of Thermodynamics is a statement of the conservation of energy. It expresses that the total energy of an isolated system remains constant — energy can be transferred or transformed, but it cannot be created or destroyed.

Option A: Direction of energy transfer
This option is incorrect.
While the first law deals with the amount of energy transferred, it does not determine the direction of energy flow.
The Second Law of Thermodynamics addresses the direction of energy transfer — for example, heat naturally flows from a hotter body to a cooler one.

Option B: Reversible processes only
This option is incorrect.
The First Law applies to all types of processes — both reversible and irreversible. It only accounts for the total energy balance and is not concerned with the nature of the process.

Option C: Irreversible processes only
This is also incorrect.
As with Option B, the law is universal and does not distinguish between reversible and irreversible processes. It applies equally to both.

Option D: None of these
This is the correct answer.
None of the listed options correctly describe what the First Law of Thermodynamics actually deals with.
The first law is about energy conservation, not about direction (Option A), nor is it limited to any specific process type (Options B and C).

Therefore, the correct answer is: None of these.

The $${C_P}$$ and $${C_V}$$ are the amount of heat required to raise the temperature of a gas by an $${1^ \circ }C$$  under constant pressure and constant volume respectively. Since in case of constant volume the entire heat is used for raising the temperature of the gas only no work is done but in case of constant pressure process some of the heat given is used for doing work also hence more amount of heat is required in case of constant pressure process to obtain the $${1^ \circ }C$$  change in temperature of the gas. But in case of solids and liquids since volume expansivity is small the $${C_P}$$ and $${C_V}$$  values remains same.

$$\frac{{1kw}}{{ton}} = \frac{{3.516}}{{c.o.p}}$$

For an azeotropic mixture since the composition of a constituent remains same in vapour and liquid one of the variable to define the system reduces.
So, $$f = C - \emptyset + 2$$
Given number of components $$= 2,$$  number of phases $$= 2$$
So, degree of freedom $$= 1$$

We know : $$G = {G^ \circ } + RTln\frac{f}{{{P^ \circ }}}$$
$$ \Rightarrow $$ where $${G^ \circ }$$ and $${P^ \circ }$$ are at standard states
So, we can say when $${P^ \circ } \to 0, \Rightarrow {G^ \circ } \to \infty $$

Air cycle has minimum coefficient of performance.