Chemical Thermodynamics — JEE Main PYQs

Which of the following graphs between pressure 'P' versus volume 'V' represent the maximum work done?

For the reaction, ${\mathrm{N}}_2{\mathrm{O}}_4\rightleftharpoons 2{\mathrm{NO}}_2$, graph is plotted as shown below. Identify correct statements.

A. Standard free energy change for the reaction is $-5.40\mathrm{kJ}{\mathrm{mol}}^{-1}$.
B. As $\Delta G^{\ominus }$ in graph i …

Use the following data:
| …

Dissociation of a gas ${\mathrm{A}}_2$ takes place according to the following chemical reactions. At equilibrium, the total pressure is 1 bar at 300 K.
${\mathrm{A}}_2(\mathrm{g})\rightleftharpoons 2\mathrm{A}(\mathrm{g})$
The standard Gibbs energy of formation of the involv …

Consider the following data:
${\Delta }_{\mathrm{f}}{\mathrm{H}}^{\Theta }$(methane, g)$=-\mathrm{X}\mathrm{kJ}{\mathrm{mol}}^{-1}$
Enthalpy of sublimation of graphite $=\mathrm{Y}\mathrm{kJ}{\mathrm{mol}}^{-1}$
Dissociation enthalpy of …

If the enthalpy of sublimation of Li is $155{\mathrm{kJ}\mathrm{mol}}^{-1}$, enthalpy of dissociation of ${\mathrm{F}}_2$ is $150{\mathrm{kJ}\mathrm{mol}}^{-1}$, ionization enthalpy of Li is $520{\mathrm{kJ}\mathrm{mol}}^{-1}$, electron gain enthalpy of F is $-313{\mathrm{kJ}\mathrm{mol}}^{-1}$, standard enthalpy o …

A cup of water at $5^{\circ }\mathrm{C}$ (system) is placed in a microwave oven and the oven is turned on for one minute during which, the water begins to boil. Which of the following option is true?

It is noticed that ${\mathrm{Pb}}^{2+}$ is more stable than ${\mathrm{Pb}}^{4+}$ but ${\mathrm{Sn}}^{2+}$ is less stable than ${\mathrm{Sn}}^{4+}$. Observe the following reactions …

Match the List-I with List-II

List-I (Isothermal process for ideal gas system) | List-II Work done (${\mathbf{V}}_{\mathbf{f}}>{\mathbf{V}}_{\mathbf{i}}$)

Choose the correct answer from the options given below :

The heat of atomisation of methane and ethane are 'x' ${\mathrm{kJ}\mathrm{mol}}^{-1}$ and 'y' ${\mathrm{kJ}\mathrm{mol}}^{-1}$ respectively. The longest wavelength ($\lambda$) of light capable of breaking the $\mathrm{C}-\mathrm{C}$ bond can be expressed in SI unit as:

$20.0{\mathrm{dm}}^3$ of an ideal gas ' X ' at 600 K and 0.5 MPa undergoes isothermal reversible expansion until pressure of the gas is 0.2 MPa . Which of the following option is correct?
(Given: $\log 2=0.3010$ and $\log 5=0.6989$ )

The plot of ${\log }_{10}\mathrm{K}$ vs $\frac{1}{\mathrm{T}}$ gives a straight line. The intercept and slope respectively are (where K is equilibrium constant).

Consider the following data
(i) $2\mathrm{Al}(\mathrm{s})+6\mathrm{HCl}(\mathrm{aq})\to {\mathrm{Al}}_2{\mathrm{Cl}}_6(\mathrm{aq})+3{\mathrm{H}}_2(\mathrm{g})+1200\mathrm{kJ}/\mathrm{mol}$.
(ii) …

At the transition temperature $\mathrm{T}$, $\mathrm{A}\rightleftharpoons \mathrm{B}$ and $\Delta {\mathrm{G}}^0=105-35\log \mathrm{T}$ where A and B are two states of substance X. The transition temperature in ${}^{\circ }\mathrm{C}$ when pressure is 1 atm is ______. (Nearest i …

Given below are two statements:

Statement I: For an ideal gas, heat capacity at constant volume is always greater than the heat capacity at constant pressure.

Statement II: In a constant volume process, no work is produced and all the heat withdrawn goes into the chaotic motion …

Gas 'A' undergoes change from state 'X' to state 'Y'. In this process, the heat absorbed and work done by the gas is 10 J and 18 J respectively. Now gas is brought back to state 'X' by another process during which 6 J of heat is evolved. In the reverse process of 'Y' to 'X',

If 3.365 g of ethanol ($l$) burnt completely in a bomb calorimeter at 298.15 K, the heat produced is 99.472 kJ. The $|\Delta {\mathrm{H}}_{\mathrm{f}}^{\circ }|$ of ethanol at 298.15 K is _____ $\times 10^2{\mathrm{kJ}\mathrm{mol}}^{-1}$. (Nearest integer)
Given:
Standard enthalpy of comb …

For the following reaction at 50°C and at 2 atm pressure,
2 N₂O₅(g) ⇌ 2 N₂O₄(g) + O₂(g)
N₂O₅ is 50% dissociated.
The magnitude of standard free energy change at this temperature is x.
x = _____ J mol⁻¹ [Nearest integer].
Given: R = 8.314 J mol⁻¹ K⁻¹, log 2 = 0.30, log 3 = 0.48, l …

The values of pressure equilibrium constant recorded at different temperatures for the following equilibrium reaction have been given below:
$\mathrm{A}(\mathrm{g})\rightleftharpoons \mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})$

| $\frac{1}{\mathrm{T}}({\mathrm{K}}^{-1})$ | …

Consider the following data for the reaction
${\mathrm{X}}_2(\mathrm{g})+{\mathrm{Y}}_2(\mathrm{g})\rightleftharpoons 2\mathrm{XY}(\mathrm{g})$
at $600\mathrm{K}$. The ${\Delta }_{\mathrm{r}}{\mathrm{G}}^{\ominus }$ (in $\mathrm{kJ}{\mathrm{mol}}^{-1}$) for the reaction i …

The correct order of molar heat capacities measured at 298 K and 1 bar is :

Arrange the following isothermal processes in order of the magnitude of the work ( $p-V$ ) involved between states 1 and 2 .
A. Expansion in single stage ${\mathrm{w}}_{\mathrm{A}}$
B. Expansion in multi stages ${\mathrm{w}}_{\mathrm{B}}$
C. Compression in single stage …

Consider the reaction $\mathrm{X}\rightleftharpoons \mathrm{Y}$ at 300 K. If $\Delta {\mathrm{H}}^{\theta }$ and K are $28.40\mathrm{kJ}{\mathrm{mol}}^{-1}$ and $1.8\times 10^{-7}$ at the same temperature, then the magnitude of $\Delta {\mathrm{S}}^{\theta }$ for the reaction in …

In a closed flask at 600 K, one mole of X₂Y₄(g) attains equilibrium as given below:

X₂Y₄(g) ⇌ 2XY₂(g)

At equilibrium, 75% X₂Y₄(g) was dissociated and the total pressure is 1 atm. The magnitude of ΔᵣG° (in kJ mol⁻¹) at this temperature is _____. (Nearest Integer)

(Given: R = 8. …

Consider the reaction :
$2{\mathrm{H}}_2\mathrm{S}(\mathrm{g})+3{\mathrm{O}}_2(\mathrm{g})\to 2{\mathrm{H}}_2\mathrm{O}(\mathrm{l})+2{\mathrm{SO}}_2(\mathrm{g})$

The magnitude of enthalpy change for the reaction in $\mathrm{kJ}{\mathrm{mol}}^{-1}$ is ____. (Neares …

A liquid when kept inside a thermally insulated closed vessel at $25^{\circ }\mathrm{C}$ was mechanically stirred from outside. What will be the correct option for the following thermodynamic parameters ?

Match List-I with List-II.

List-I (Partial Derivatives):
(A) ${\left(\frac{\partial \mathrm{G}}{\partial \mathrm{T}}\right)}_{\mathrm{P}}$
(B) ${\left(\frac{\partial \mathrm{H}}{\partial \mathrm{T}}\right)}_{\mathrm{P}}$
(C) …

Consider the following cases of standard enthalpy of reaction ( $\Delta {\mathrm{H}}_{\mathrm{r}}^{\mathrm{o}}$ in $\mathrm{kJ}{\mathrm{mol}}^{-1}$ ) …

Let us consider an endothermic reaction which is non-spontaneous at the freezing point of water. However, the reaction is spontaneous at boiling point of water. Choose the correct option.

Standard entropies of $X_2,Y_2$ and $X{Y}_5$ are 70, 50 and $110\mathrm{J}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}$ respectively. The temperature in Kelvin at which the reaction …

Which of the following mixing of 1 M base and 1 M acid leads to the largest increase in temperature?

$\mathrm{S}(\mathrm{g})+\frac{3}{2}{\mathrm{O}}_2(\mathrm{g})\to {\mathrm{SO}}_3(\mathrm{g})+2\mathrm{x}\mathrm{kcal}$
${\mathrm{SO}}_2(\mathrm{g})+\frac{1}{2}{\mathrm{O}}_2(\mathrm{g})\to {\mathrm{SO}}_3(\mathrm{g})+\mathrm{y}\mathrm{kcal}$
The he …

Ice at $-5^{\circ }\mathrm{C}$ is heated to become vapor with temperature of $110^{\circ }\mathrm{C}$ at atmospheric pressure. The entropy change associated with this process can be obtained from:

The standard enthalpy and standard entropy of decomposition of ${\mathrm{N}}_2{\mathrm{O}}_4$ to ${\mathrm{NO}}_2$ are $55.0\mathrm{kJ}{\mathrm{mol}}^{-1}$ and $175.0\mathrm{J}/\mathrm{K}/\mathrm{mol}$ respectively. The standard free energy change for this reacti …

The formation enthalpies, ΔH°_f for H₍g₎ and O₍g₎ are 220.0 and 250.0 kJ mol⁻¹, respectively, at 298.15 K, and ΔH°_f for H₂O₍g₎ is -242.0 kJ mol⁻¹ at the same temperature. The average bond enthalpy of the O-H bond in water at 298.15 K is ______ kJ mol⁻¹ (nearest integer).

The effect of temperature on spontaneity of reactions are represented as:
| (D) - | + | any T | spontaneo …

The bond dissociation enthalpy of ${\mathrm{X}}_2\Delta {\mathrm{H}}_{\text{bond }}^{\mathrm{o}}$ calculated from the given data is ____ $\mathrm{kJ}{\mathrm{mol}}^{-1}$.
(Nearest integer) …

Consider the following data :

Heat of formation of ${\mathrm{CO}}_2(\mathrm{g})=-393.5\mathrm{kJ}{\mathrm{mol}}^{-1}$
Heat of formation of ${\mathrm{H}}_2\mathrm{O}(\mathrm{l})=-286.0\mathrm{kJ}{\mathrm{mol}}^{-1}$
Heat of combustion of benzene …

500 J of energy is transferred as heat to 0.5 mol of Argon gas at 298 K and 1.00 atm. The final temperature and the change in internal energy respectively are:

Given: $\mathrm{R}=8.3\mathrm{J}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}$

If $\mathrm{C}$ (diamond) $\to \mathrm{C}$ (graphite) $+\mathrm{X}\mathrm{kJ}{\mathrm{mol}}^{-1}$ …

Two vessels A and B are connected via stopcock. The vessel A is filled with a gas at a certain pressure. The entire assembly is immersed in water and is allowed to come to thermal equilibrium with water. After opening the stopcock the gas from vessel A expands into vessel B and n …

Arrange the following in order of magnitude of work done by the system / on the system at constant temperature :
(a) $\left|{\mathrm{W}}_{\text{reversible }}\right|$ for expansion in infinite stage.
(b) $\left|{\mathrm{w}}_{\text{irreversible }}\right|$ for expansion in single …

Which of the following graphs correctly represents the variation of thermodynamic properties of Haber's process?

Given : …

Consider the given data :
(a)

(b) …

Let us consider a reversible reaction at temperature, T.

In this reaction, both $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ were observed to have positive values. If the equilibrium temperature is Te, then the reaction becomes spontaneous at:

One mole of an ideal gas expands isothermally and reversibly from $10{\mathrm{dm}}^3$ to $20{\mathrm{dm}}^3$ at $300\mathrm{K}$. $\Delta \mathrm{U}$, q and work done in the process respectively are:
Given: $\mathrm{R}=8.3{\mathrm{JK}}^{-1}$ and mol${}^{-1}$
In …

The hydration energies of ${\mathrm{K}}^{+}$ and ${\mathrm{Cl}}^{-}$ are -x and -y $\mathrm{kJ}/\mathrm{mol}$ respectively. If lattice energy of KCl is -z $\mathrm{kJ}/\mathrm{mol}$, then the heat of solution of KCl is :

The correct statement amongst the following is :

Total enthalpy change for freezing of 1 mol of water at $10^{\circ }\mathrm{C}$ to ice at $-10^{\circ }\mathrm{C}$ is ____

(Given : ${\Delta }_{\text{fus }}\mathrm{H}=\mathrm{xkJ}/\mathrm{mol}$ …