Thermodynamics

The work done during reversible isothermal expansion of one mole of hydrogen gas at \(25^\circ C\) from pressure of 20 atmosphere to 10 atmosphere is:
(Given \(\mathrm{R}=2.0\mathrm{cal}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}\))

[NEET 2024]

In which of the following processes entropy increases?

A. A liquid evaporates to vapour.
B. Temperature of a crystalline solid lowered from 130 K to 0 K.
C. \(2{\mathrm{NaHCO}}_{3(\mathrm{s})}\to {\mathrm{Na}}_{2}{\mathrm{CO}}_{3(\mathrm{s})}+{\mathrm{CO}}_{2(\mathrm{g})}+{\mathrm{H}}_{2}{\mathrm{O}}_{(\mathrm{g})}\)
D. \({\mathrm{Cl}}_{2(\mathrm{g})}\to 2{\mathrm{Cl}}_{(\mathrm{g})}\)

Choose the correct answer from the options given below

[NEET 2024]

The work done during reversible isothermal expansion of one mole of hydrogen gas at \(25^\circ C\) from pressure of 20 atmosphere to 10 atmosphere is:
(Given \(\mathrm{R}=2.0\mathrm{cal}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}\))

In which of the following processes entropy increases?
A. A liquid evaporates to vapour.
B. Temperature of a crystalline solid lowered from 130 K to 0 K.
C. \(2NaHC{O}_{3(s)}\to N{a}_{2}C{O}_{3(s)}+C{O}_{2(g)}+{H}_{2}{O}_{(g)}\)
D. \(C{l}_{2(g)}\to 2C{l}_{(g)}\)

Choose the correct answer from the options given below:

A protein undergoes reversible thermal denaturation from its initial state N to denatured state D according to \(\mathrm{N}⇌\mathrm{D}\). At 60ºC, the concentrations of both N and D are equal at equilibrium, and the standard enthalpy change of denaturation is 666 \(\mathrm{kJ}{\mathrm{mol}}^{-1}\). The standard entropy change (\(∆\mathrm{S}º\) in \(\mathrm{kJ}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}\)) of the protein upon denaturation at 60ºC is closest to

[Re-NEET 2026]

For the following reaction at \(\mathrm{300 ~K}\)

\({A}_{2}(g)+3{B}_{2}(g)\to 2A{B}_{3}(g)\)

the enthalpy change is \(\mathrm{+15 ~kJ}\), then the internal energy change is

[Re-NEET 2024]

For the following reaction at \(\mathrm{300 ~K}\)

\({A}_{2}(g)+3{B}_{2}(g)\to 2A{B}_{3}(g)\)

the enthalpy change is \(\mathrm{+15 ~kJ}\), then the internal energy change is

[Re-NEET 2024]

Choose the correct statement for the work done in the expansion and heat absorbed or released when 5 litres of an ideal gas at 10 atmospheric pressure isothermally expands into vacuum until volume is 15 litres

[Re-NEET 2024]

Choose the correct statement for the work done in the expansion and heat absorbed or released when 5 litres of an ideal gas at 10 atmospheric pressure isothermally expands into vacuum until volume is 15 litres :

Which one among the following is the correct option for right relationship between \({\mathrm{C}}_{\mathrm{P}}\&{\mathrm{C}}_{\mathrm{V}}\) for one mole of ideal gas?

[NEET 2021]

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

Given :
\[\begin{aligned}& \Delta H _{ f }^\theta\left( Al _2 O _3\right)=-1700 kJ mol ^{-1} \\& \Delta H _{ f }^\theta\left( Fe _2 O _3\right)=-840 kJ mol ^{-1}\end{aligned}\]

Molar mass of \(Fe , Al\) and \(O\) are 56, 27 and \(16 g mol ^{-1}\) respectively.

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

[JEE Main 2023, 8 Apr (Shift 1)]

At standard conditions, if the change in the enthalpy for the following reaction is \( -109 \mathrm{~kJ} \mathrm{~mol}^{-1} \)

\( \mathrm{H}_{2(\mathrm{~g})}+\mathrm{Br}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{HBr}_{(\mathrm{g})} \)

Given that bond energy of \( \mathrm{H}_{2} \) and \( \mathrm{Br}_{2} \) is \( 435 \mathrm{~kJ} \mathrm{~mol}^{-1} \) and 192 \( \mathrm{kJ} \mathrm{mol}^{-1} \), respectively, what is the bond energy (in \( \mathrm{kJ} \mathrm{mol}^{-1} \) ) of \( \mathrm{HBr} \) ?

[Re-NEET 2020]

For the reaction, \( 2 \mathrm{Cl}(\mathrm{g}) \rightarrow \mathrm{Cl}_{2}(\mathrm{~g}) \), the correct option is:

[NEET 2020]

If for a certain reaction \( \Delta_{\mathrm{r}} \mathrm{H} \) is \( 30 \mathrm{~kJ} \mathrm{~mol}^{-1} \) at \( 450 \mathrm{~K} \), the value of \( \Delta_{\mathrm{r}} \mathrm{S} \) (in \( \mathrm{JK}^{-1} \mathrm{~mol}^{-1} \) ) for which the same reaction will be spontaneous at the same temperature is

[Re-NEET 2020]

Which amongst the following options is the correct relation between change in enthalpy and change in internal energy?

[NEET 2023]

For irreversible expansion of an ideal gas under isothermal condition, the correct option is:

[NEET 2021]

For the combustion reaction at 298 K

\(2\mathrm{Ag}(\mathrm{s})+1/2{\mathrm{O}}_{2}(\mathrm{g})\to 2{\mathrm{Ag}}_{2}\mathrm{O}(\mathrm{s})\)

Which of the following alternatives is correct?

Which of the following relations are correct?
(A) \(\Delta U = q + p \Delta V\)
(B) \(\Delta G =\Delta H - T \Delta S\) (at const. T & P)
(C) \(\Delta S =\frac{ q _{ rev }}{ T }\)
(D) \(\Delta H =\Delta U -\Delta nRT\)

Choose the most appropriate answer from the options given below

[JEE Main 2023, 29 Jan (Shift 2)]