Which among the following statements about open, closed, and isolated systems is correct?

1.	The presence of reacting species in a covered beaker represents an open system.
2.	In a closed system, there is an exchange of both energy and matter between the system and its surroundings.
3.	A system containing reactants in a closed vessel made of copper is an example of a closed system.
4.	A system containing reactants in a thermos flask or any other closed, insulated vessel is an example of a closed system.

What happens to the specific heat of a gas when its volume is reduced to half of its initial value?

${The\; standard\; internal\; energy\; change\; of\; formation,\; \Delta fU°,\; of\; CH₄(g)\; at\; a\; certain\; temperature\; is\; –393\; kJ\; mol⁻¹.}_{}$

Find the value of the standard enthalpy of formation (ΔfH°).
1. Zero

2. Less than ΔfU°

3. Greater than ΔfU°

4. Equal to ΔfU°

In an adiabatic process, no transfer of heat takes place between the system and its surroundings. The correct option for free expansion of an ideal gas under adiabatic condition from the following is:

1. $\mathrm{q}=0,<mspace\; width="1em"></mspace>∆\mathrm{T}\ne 0,<mspace\; width="1em"></mspace>\mathrm{W}=0$

2. $\mathrm{q}\ne 0,<mspace\; width="1em"></mspace>∆\mathrm{T}=0,<mspace\; width="1em"></mspace>\mathrm{W}=0$

3. $\mathrm{q}=0,<mspace\; width="1em"></mspace>∆\mathrm{T}=0,<mspace\; width="1em"></mspace>\mathrm{W}=0$

4. $\mathrm{q}=0,<mspace\; width="1em"></mspace>∆\mathrm{T}=0,<mspace\; width="1em"></mspace>\mathrm{W}\ne 0$

The pressure-volume work for an ideal gas can be calculated by using the expression $\mathrm{W}={\int }_{{\mathrm{V}}_{\mathrm{i}}}^{{\mathrm{V}}_{\mathrm{f}}}{\mathrm{p}}_{\mathrm{ext}}d\mathrm{V}$.

The work can also be calculated from the pV-plot by using the area under the curve within the specified limits.
An ideal gas is compressed (a) reversibly or (b) irreversibly from volume ${\mathrm{V}}_{\mathrm{i}}$ to ${\mathrm{V}}_{\mathrm{f}}$.
The correct option is:

1. $\mathrm{W}<mspace\; width="1em"></mspace>\left(\mathrm{reversible}\right)=\mathrm{W}<mspace\; width="1em"></mspace>\left(\mathrm{irreversible}\right)$

2. $\mathrm{W}<mspace\; width="1em"></mspace>\left(\mathrm{reversible}\right)<\mathrm{W}\hspace{0.17em}\left(\mathrm{irreversible}\right)$

3. $\mathrm{W}<mspace\; width="1em"></mspace>(\mathrm{reversible})\; >\mathrm{W}<mspace\; width="1em"></mspace>(\mathrm{irreversible})$

4. $\mathrm{W}<mspace\; width="1em"></mspace>\left(\mathrm{reversible}\right)=\mathrm{W}<mspace\; width="1em"></mspace>\left(\mathrm{irreversible}\right)+{\mathrm{p}}_{\mathrm{ext}}.∆\mathrm{V}$

The entropy change can be calculated by using the expression $∆\mathrm{S}=\frac{{\mathrm{q}}_{\mathrm{rev}}}{\mathrm{T}}$. When water freezes in a glass beaker, the correct statement among the following is:

Based on the reactions, ascertain the valid algebraic relationship:
$\left(i\right)$ $C\left(g\right)$ $+4H$ $\left(g\right)$ $\to C{H}_4\left(g\right);$ $$
$∆H_r$ $=x$ $kJ$ $mo{l}^{-1}$
$\left(ii\right)$ $C\left(graphite\right)$ $+$ $2H_2$ $\left(g\right)$ $\to$ $$ $C{H}_4;$ $$
$∆H_r$ $$ $=$ $y$ $kJ$ $mo{l}^{-1}$

The enthalpies of elements in their standard states are taken as zero. The enthalpy of formation of a compound is :

Consider the following statement:

"A thermodynamic quantity is a state function"

The correct option is-

1. Used to determine heat changes

2. Whose value is independent of the path

3. Used to determine pressure-volume work

4. Whose value depends on temperature only.

What is a necessary condition for an adiabatic process to occur?

1. ∆T = 0

2. ∆P = 0

3. q = 0

4. w = 0