Chemical Thermodynamics — JEE Main PYQs

Resonance in ${\mathrm{X}}_2\mathrm{Y}$ can be represented as

(see structure)

The enthalpy of formation of ${\mathrm{X}}_2\mathrm{Y}$ ($\mathrm{X}\equiv \mathrm{X}(\mathrm{g})+\frac{1}{2}\mathrm{Y}=\mathrm{Y}(\mathrm{g})\to {\mathrm{X}}_2\mathrm{Y}(\mathrm{g})$) is 80 kJ mo …

The enthalpy of formation of ethane (C₂H₆) from ethylene by addition of hydrogen where the bond energies of C-H, C-C, H-H are 414 kJ, 347 kJ, 615 kJ and 435 kJ respectively is - ____ kJ.

Three moles of an ideal gas are compressed isothermally from 60 L to 20 L using constant pressure of 5 atm. Heat exchange Q for the compression is - _____ Lit. atm.

Given below are two statements : One is labelled as Assertion (A) and the other is labelled as Reason (R)
Assertion (A): Enthalpy of neutralisation of strong monobasic acid with strong monoacidic base is always $-57\mathrm{kJ}{\mathrm{mol}}^{-1}$
Reason (R): Enthalpy of neutr …

The heat of combustion of solid benzoic acid at constant volume is -321.30 kJ at $27^{\circ }\mathrm{C}$. The heat of combustion at constant pressure is ( $-321.30-x\mathrm{R}$ ) kJ , the value of x is ____

Combustion of 1 mole of benzene is expressed at
${\mathrm{C}}_6{\mathrm{H}}_6(1)+\frac{15}{2}{\mathrm{O}}_2(\mathrm{g})\to {\mathrm{CO}}_2(\mathrm{g})+3{\mathrm{H}}_2\mathrm{O}(1)$.
The standard enthalpy of combustion of 2 mol of benzene is …

An ideal gas, ${\overline{C}}_V=\frac{5}{2}R$, is expanded adiabatically against a constant pressure of 1 atm until it doubles in volume. If the initial temperature and pressure is 298 K and 5 atm, respectively then the final temperature is ______ K (nearest integer).
[ …

For the reaction at $298\mathrm{K}$, $2\mathrm{A}+\mathrm{B}\to \mathrm{C}$. $\Delta \mathrm{H}=400\mathrm{kJ}{\mathrm{mol}}^{-1}$ and $\Delta \mathrm{S}=0.2\mathrm{kJ}{\mathrm{mol}}^{-1}{\mathrm{K}}^{-1}$. The reaction will become spontaneous above ______ K.

${\Delta }_{\text{vap}}{\mathrm{H}}^{\ominus }$ for water is $+40.49\mathrm{kJ}{\mathrm{mol}}^{-1}$ at 1 bar and $100^{\circ }\mathrm{C}$. Change in internal energy for this vapourisation under same condition is ____ kJ ${\mathrm{mol}}^{-1}$. (Integer answer)
(Given …

Consider the figure provided.
1 mol of an ideal gas is kept in a cylinder, fitted with a piston, at the position A , at $18^{\circ }\mathrm{C}$. If the piston is moved to position B , keeping the temperature unchanged, then ' x ' L atm work is done in this reversible process. …

The heat of solution of anhydrous ${\mathrm{CuSO}}_4$ and ${\mathrm{CuSO}}_4\cdot 5{\mathrm{H}}_2\mathrm{O}$ are $-70\mathrm{kJ}{\mathrm{mol}}^{-1}$ and $+12\mathrm{kJ}{\mathrm{mol}}^{-1}$ respectively.

The heat of hydration of ${\mathrm{CuSO}}_4$ to …

When equal volume of 1 M HCl and $1\mathrm{M}{\mathrm{H}}_2{\mathrm{SO}}_4$ are separately neutralised by excess volume of 1 M NaOH solution. X and y kJ of heat is liberated respectively. The value of $\mathrm{y}/\mathrm{x}$ is ______.

When $\Delta H_{\text{vap}}=30kJ/mol$ and $\Delta S_{\text{vap}}=75{\mathrm{J}\mathrm{mol}}^{-1}{\mathrm{K}}^{-1}$, then the temperature of vapour, at one atmosphere is $\_\_\_\_$ K.

If three moles of an ideal gas at 300 K expand isothermally from $30{\mathrm{dm}}^3$ to $45{\mathrm{dm}}^3$ against a constant opposing pressure of 80 kPa, then the amount of heat transferred is ____ J.

For a certain reaction at $300\mathrm{K},\mathrm{K}=10$, then $\Delta {\mathrm{G}}^{\circ }$ for the same reaction is - ____ $\times 10^{-1}\mathrm{kJ}{\mathrm{mol}}^{-1}$.
(Given $\mathrm{R}=8.314{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}$ )

Choose the correct option for free expansion of an ideal gas under adiabatic condition from the following :

For a certain thermochemical reaction $\mathrm{M}\to \mathrm{N}$ at $\mathrm{T}=400\mathrm{K},\Delta {\mathrm{H}}^{\ominus }=77.2\mathrm{kJ}{\mathrm{mol}}^{-1},\Delta \mathrm{S}=122{\mathrm{JK}}^{-1}$, $\log$ equilibrium constant $(\log \mathrm{K})$ is - $\_\_\_\_$ …

Which of the following is not correct?

Standard enthalpy of vapourisation for $\mathrm{CCl}{}_4$ is $30.5{\text{ kJ mol}}^{-1}$. Heat required for vapourisation of $284\text{ g}$ of $\mathrm{CCl}{}_4$ at constant temperature is _____ kJ.
(Given molar mass in ${\text{g mol}}^{-1}$; $\mathrm{C}=12$, $\mathrm{Cl}=35.5$)

Consider the following reaction at 298 K.
$\frac{3}{2}{\mathrm{O}}_{2(\mathrm{g})}\rightleftharpoons {\mathrm{O}}_{3(\mathrm{g})}.{\mathrm{K}}_{\mathrm{p}}=2.47\times 10^{-29}$.
${\Delta }_{\mathrm{r}}{\mathrm{G}}^{\Theta }$ for the reaction is ______ kJ. (Given R …

An ideal gas undergoes a cyclic transformation starting from the point A and coming back to the same point by tracing the path $\mathrm{A}\to \mathrm{B}\to \mathrm{C}\to \mathrm{A}$ as shown in the diagram. The total work done in the process is ___ …

If 5 moles of an ideal gas expands from 10 L to a volume of 100 L at 300 K under isothermal and reversible condition then work, w, is $-x\mathrm{J}$. The value of $X$ is ____.
(Given $\mathrm{R}=8.314\mathrm{J}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}$)

Two reactions are given below:
$2{\mathrm{Fe}}_{(\mathrm{s})}+\frac{3}{2}{\mathrm{O}}_{2(\mathrm{g})}\to {\mathrm{Fe}}_2{\mathrm{O}}_{3(\mathrm{s})},\Delta {\mathrm{H}}^{\mathrm{o}}=-822\mathrm{kJ}/\mathrm{mol}$ …

Consider the graph of Gibbs free energy G vs Extent of reaction. The number of statement/s from the following which are true with respect to points (a), (b) and (c) is ______

A. Reaction is spontaneous at (a) and (b)
B. Reaction is at equilibrium at point (b) and nonspontaneous …

The value of $\log \mathrm{K}$ for the reaction $\mathrm{A}\leftrightharpoons \mathrm{B}$ at 298 K is ______ (Nearest integer)

Given: $\Delta {\mathrm{H}}^0=-54.07\mathrm{kJ}{\mathrm{mol}}^{-1}$
$\Delta {\mathrm{S}}^{\circ }=10{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}$
(Take …

Consider the following date

Heat of combustion of ${\mathrm{H}}_2(\mathrm{g})=-241.8\mathrm{kJ}{\mathrm{mol}}^{-1}$

Heat of combustion of $\mathrm{C}(\mathrm{s})=-393.5\mathrm{kJ}{\mathrm{mol}}^{-1}$

Heat of combustion of …

For complete combustion of ethene.
${\mathrm{C}}_2{\mathrm{H}}_4(\mathrm{g})+3{\mathrm{O}}_2(\mathrm{g})\to 2{\mathrm{CO}}_2(\mathrm{g})+2{\mathrm{H}}_2\mathrm{O}(\mathrm{l})$ the amount of heat produced as measured in bomb calorimeter is …

Gibbs energy vs T plot for the formation of oxides is given below:

For the given diagram, the correct statement is-

The number of endothermic process/es from the following is ______
A. ${\mathrm{I}}_2(\mathrm{g})\to 2\mathrm{I}(\mathrm{g})$
B. $\mathrm{HCl}(\mathrm{g})\to \mathrm{H}(\mathrm{g})+\mathrm{Cl}(\mathrm{g})$
C. …

When a 60 W electric heater is immersed in a gas for 100s in a constant volume container with adiabatic walls, the temperature of the gas rises by $5^{\circ }\mathrm{C}$. The heat capacity of the given gas is ______ J K${}^{-1}$ (Nearest integer)

Given
(A) $2\mathrm{CO}(\mathrm{g})+{\mathrm{O}}_2(\mathrm{g})\to 2{\mathrm{CO}}_2(\mathrm{g})\Delta {\mathrm{H}}_1^{\theta }=-\mathrm{x}\mathrm{kJ}{\mathrm{mol}}^{-1}$
(B) C(graphite) …

Solid fuel used in rocket is a mixture of ${\mathrm{Fe}}_2{\mathrm{O}}_3$ and Al (in ratio $1:2$ ). The heat evolved ( kJ ) per gram of the mixture is ____ (Neatest integer)

Given : …

The total number of intensive properties from the following is ____
Volume, Molar heat capacity, Molarity, ${\mathrm{E}}^{\theta }$ cell, Gibbs free energy change, Molar mass, Mole

One mole of an ideal gas at 350 K is in a 2.0 L vessel of thermally conducting walls, which are in contact with the surroundings. It undergoes isothermal reversible expansion from 2.0 L to 3.0 L (the pressure figure printed alongside is a redundant distractor and does not enter t …

For the reaction ${\mathrm{A}}_2+{\mathrm{B}}_2\to 2AB$, the enthalpy change of the reaction as written is $\Delta {\mathrm{H}}^0=-200\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$. AB, ${\mathrm{A}}_2$ and ${\mathrm{B}}_2$ are diatomic molecules. If the bond enthalpies of ${\mathrm{A}}_2$, …

What happens when methane undergoes combustion in systems A and B respectively?

Identify the correct order of standard enthalpy of formation of sodium halides.

30.4 kJ of heat is required to melt one mole of sodium chloride and the entropy change at the melting point is $28.4\mathrm{J}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}$ at 1 atm. The melting point of sodium chloride is ______ K
(Nearest Integer)

At $25^{\circ }\mathrm{C}$, the enthalpy of the following processes are given:
${\mathrm{H}}_2(\mathrm{g})+{\mathrm{O}}_2(\mathrm{g})\to 2\mathrm{OH}(\mathrm{g})\Delta {\mathrm{H}}^{\mathrm{o}}=78\mathrm{kJ}{\mathrm{mol}}^{-1}$ …

For independent process at 300 K.

The number of non-spont …

One mole of an ideal monoatomic gas is subjected to changes as shown in the graph. The magnitude of the work done (by the system or on the system) is ____ J (nearest integer).

Given: $\log 2=0.3,\ln 10=2.3$

An athlete is given 100 g of glucose $({\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6)$ for energy. This is equivalent to 1800 kJ of energy. The $50\%$ of this energy gained is utilized by the athlete for sports activities at the event. In order to avoid storage of energy, the we …

28.0 L of ${\mathrm{CO}}_2$ is produced on complete combustion of 16.8 L gaseous mixture of ethene and methane at $25^{\circ }\mathrm{C}$ and 1 atm. Heat evolved during the combustion process is ____ kJ.

Given: …

Consider the following reaction approaching equilibrium at $27^{\circ }\mathrm{C}$ and 1 atm pressure
$\mathrm{A}+\mathrm{B}\underset{{\mathrm{K}}_{\mathrm{r}}=10^2}{\stackrel{{\mathrm{K}}_{\mathrm{f}}=10^3}{\rightleftharpoons }}\mathrm{C}+\mathrm{D}$
The standard Gibb's energy …

Which of the following relations are correct?
(A) $\Delta \mathrm{U}=\mathrm{q}+\mathrm{p}\Delta \mathrm{V}$
(B) $\Delta \mathrm{G}=\Delta \mathrm{H}-\mathrm{T}\Delta \mathrm{S}$
(C) $\Delta \mathrm{S}=\frac{{\mathrm{q}}_{\text{rev }}}{\mathrm{T}}$
(D) …

When 2 litre of ideal gas expands isothermally into vacuum to a total volume of 6 litre, the change in internal energy is ______ J. (Nearest integer)

The correct order of bond enthalpy $\left(\mathrm{kJ}{\mathrm{mol}}^{-1}\right)$ is :

0.3 g of ethane undergoes combustion at $27^{\circ }\mathrm{C}$ in a bomb calorimeter. The temperature of calorimeter system (including the water) is found to rise by $0.5^{\circ }\mathrm{C}$. The heat evolved during combustion of ethane at constant pressure is $\_\_\_\_$ …

Enthalpies of formation of ${\mathrm{CCl}}_4(\mathrm{g}),{\mathrm{H}}_2\mathrm{O}(\mathrm{g}),{\mathrm{CO}}_2(\mathrm{g})$ and
$\mathrm{HCl}(\mathrm{g})$ are $-105,-242,-394$ and $-92\mathrm{kJ}{\mathrm{mol}}^{-1}$ respectively. The magnitude of enthalpy of the rea …

1 mole of ideal gas is allowed to expand reversibly and adiabatically from a temperature of $27^{\circ }\mathrm{C}$. The work done is $3\mathrm{kJ}{\mathrm{mol}}^{-1}$. The final temperature of the gas is ____ K (Nearest integer). Given …