Thermodynamics

5 moles of a gas is allowed to pass through a series of changes as shown in the graph, in a cyclic process. The processes $C \rightarrow A, B \rightarrow C$ and $A \rightarrow B$ respectively are

1 mole of an ideal gas is allowed to expand isothermally and reversibly from $\mathrm{1L}$ to 5 L at 300 K . The change in enthalpy (in kJ ) is $\left(R=8.3 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)$

Consider the following.
Statement -I Both internal energy $(U)$ and work $(W)$ are state functions.
Statement-II During the free expansion of an ideal gas into vacuum, the work done is zero.
The correct answer is

The signs of $\Delta_r H^{\circ}$ and $\Delta_r S^{\circ}$ for a reaction to be spontaneous at all temperature respectively are

The number of extensive and intensive properties in the list given below is respectively, density, enthalpy, mass, temperature, volume, pressure

One mole of ethanol ( $l$ ) was completely burnt in oxygen to form $\mathrm{CO}_2(\mathrm{~g})$ and $\mathrm{H}_2 \mathrm{O}(l)$. What is the $\Delta_r H^{\circ}$ (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) for this reaction?
(The standard enthal...

The $\mathrm{C}_p$ of $\mathrm{H}_2 \mathrm{O}(l)$ is $75.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$. What is the energy (in J ) required to raise 180 g of liquid water from $10^{\circ} \mathrm{C}$ to $15^{\circ} \mathrm{C}$ ? $\lef...

If $\Delta_r H^{\ominus}$ and $\Delta_r S^{\ominus}$ are standard enthalpy change and standard entropy change respectively for a reaction, the incorrect option is

At $298 \mathrm{~K}, \Delta_r U^{\ominus}$ and $\Delta_r S^{\ominus}$ for the following reaction are -10.5 kJ and $+44.1 \mathrm{JK}^{-1} ; 2 X(\mathrm{~g})+Y(\mathrm{~g}) \longrightarrow 2 Z(\mathrm{~g})$ What is $\Delta_r G^{\ominus}$ (in...

For which reaction $\Delta H \neq \Delta U ?$

Enthalpy of formation of $\mathrm{CO}_2(\mathrm{~g}), \mathrm{H}_2 \mathrm{O}(\mathrm{l})$ and $\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6(\mathrm{~s})$ are $-393,-286$ and $-1170 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. The quantity o...

Identify the incorrect statements from the following.
I. For adiabatic process, $\Delta U=w_{\text {ad }}$
II. Enthalpy is an intensive property
III. For the process, $\mathrm{H}_2 \mathrm{O}(l) \rightarrow \mathrm{H}_2 \mathrm{O}(s)$, the ...

Identify the correct statements from the following.
I. Work is a path function.
II. Enthalpy is an extensive property.
III. Lattice enthalpy of ionic compounds can be obtained from Born-Haber cycle.

Which of the following processes entropy change $(\Delta S)$ is negative?
I. Sublimation of dry ice
II. Freezing of water
III. Crystallisation of the dissolved substance
IV. Burning of rocket fuel

One mole of $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}(l)$ was completely burnt in oxygen to form $\mathrm{CO}_2(g)$ and $\mathrm{H}_2 \mathrm{O}(l)$. The standard enthalpy of formation $\left(\Delta_f H^{\ominus}\right)$ of $\mathrm{C}_2 \math...

Consider the following reaction
\(A(g)+3 B(g) \longrightarrow 2 C(g) ; \Delta H^{\ominus}=-24 \mathrm{~kJ}\)
At $25^{\circ} \mathrm{C}$, if $\Delta G^{\ominus}$ of the reaction is -9 kJ , the standard entropy change (in $\mathrm{JK}^{-1}$...

The energy required to increase the temperature of 180 g of liquid water from $10^{\circ} \mathrm{C}$ to $15^{\circ} \mathrm{C}$ is 3765 J . What is $C_p$ of water in $\mathrm{J} \mathrm{mol}^{-1} \mathrm{~K}^{-1} ?\left(\mathrm{H}_2 \mathr...

Consider the following :
Statement I : During isothermal expansion of an ideal gas its enthalpy decreases.
Statement II : When 2.0 L of an ideal gas expands isothermally into vaccum, $\Delta U=0$.
The correct answer is :

At 273 K the maximum work done when pressure on 10 g of hydrogen is reduced from 10 atm to 1 atm under isothermal, reversible conditions is
(Assume the gas behaves ideally)
\(\left(R=83 \mathrm{Jk}^{-1} \mathrm{~mol}^{-1}\right)\)

Observe the following reactions.
I. $\mathrm{CaCO}_3(\mathrm{~s}) \longrightarrow \mathrm{CaO}(\mathrm{s})+\mathrm{CO}_2(\mathrm{~g})$
II. $\mathrm{Cl}_2(\mathrm{~g}) \longrightarrow 2 \mathrm{Cl}(\mathrm{g})$
III. $\mathrm{H}_2 \mathrm{O}(...

$A, B, C$ and $D$ are some compounds. The entnalpy of formation of $A(g), B(g), C(g)$ and $D(g)$ is $9.7,-110,81$ and $-393 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. What is $\Delta_r H$
(in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) for the gi...

What is the enthalpy change (in J ) for converting 98 of $\mathrm{H}_2 \mathrm{O}(t)+10^{\circ} \mathrm{C}$ to $\mathrm{H}_2 \mathrm{O}(l)$ at $+20^{\circ} \mathrm{C}$ ?
$$ \left(C_p\left(\mathrm{H}_2 \mathrm{O}(\eta)\right)=75 \mathrm{Jmol...

Two statements are given below.
Statement I : The reaction $\mathrm{Cr}_2 \mathrm{O}_3+2 \mathrm{Al} \longrightarrow \mathrm{Al}_2 \mathrm{O}_3+2 \mathrm{Cr}$ $\left(\Delta G^{\ominus}=-421 \mathrm{~kJ}\right)$ is thermodynamically feasible...

Observe the following reaction.

\(A B \mathrm{O}_3(\mathrm{~s}) \xrightarrow{1000 \mathrm{~K}} A \mathrm{O}(\mathrm{~s})+B \mathrm{O}_2(\mathrm{~g})\)
$\Delta_r H$ for this reaction is $x \mathrm{~kJ} \mathrm{~mol}^{-1}$. What is its $\...

At $300 \mathrm{~K}, \Delta_r G^{\Theta}$ for the reaction $A_2(g) \rightleftharpoons B_2(g)$ is $-11.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The Equilibrium constant at 300 K is approximately ( $R=8314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K...

Identify the correct statements from the following.
I. $\Delta_r G$ is zero for $A \rightleftharpoons B$ reaction.
II. The entropy of pure crystalline solids approaches. zero as the temperature approaches absolute zero.
III. $\Delta U$ of a...

Observe the following reactions.
$$ \begin{array}{ll} A B(g)+25 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow\left(25 \mathrm{H}_2 \mathrm{O}\right) A B ; & \Delta H=x \mathrm{~kJ} \mathrm{~mol}^{-1} \\ A B(g)+50 \mathrm{H}_2 \mathrm{O}(l) \lo...

The equation that represents 'coal gasification' is

The standard free energy change $\left(\Delta G^{\circ}\right)$ for the following reaction (in kJ ) at $25^{\circ} \mathrm{C}$ is

$$
3 \mathrm{Ca}(s)+2 \mathrm{Au}^{3+}(a q, 1 M) \longrightarrow 3 \mathrm{Ca}^{2+}(a q, 1 M)+2 \mathrm{Au}(...

The number of extensive properties in the following list is enthalpy, density, volume, internal energy, temperature.

Identify the correct equation relating $\Delta H, \Delta U$ and $\Delta T$ for 1 mole of an ideal gas from the following. ( $R=$ gas constant)

Identify the molecule for which the enthalpy of atomisation ( $\Delta_a H^{\ominus}$ ) and bond dissociation enthalpy $\left(\Delta_{\text {bond }} H^{\ominus}\right)$ are not equal

Observe the following reaction,
\(2 A_2(g)+B_2(g) \xrightarrow{T(\mathrm{~K})} 2 A_2 B(g)+600 \mathrm{~kJ}\)
The standard enthalpy of formation $\left(\Delta_f H^{\ominus}\right)$ of $A_2 B(g)$ is

The molar heat of fusion and vaporisation of benzene are 10.9 and $31.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. The changes in entropy for the solid $\rightarrow$ liquid and liquid $\rightarrow$ vapour trasitions for benzene are $x$ ...

The volume of an ideal gas contracts from 10.0 L to 2.0 L under an applied pressure of 2.0 atm . During contraction the system also evolved 900 J of heat. The change in internal energy (in J ) involved in the system is ( $1 \mathrm{~L} \mat...

What is the ratio of kinetic energies of 3 g of hydrogen and 4 g of oxygen at a certain temperature?

A thermodynamic process $(B \rightarrow E)$ was completed as shown below. The work done is equal to area under the limits

Given below are two statements :
Statement I For isothermal irreversible change of an ideal gas, $q=-w=p_{\text {ext }}\left(V_{\text {final }}-V_{\text {initial }}\right)$
Statement II For adiabatic change, $\Delta U=w_{\text {adiabatic }}...

Identify the incorrect statements form the following.I. $ \Delta S_{\text {pum }}=\left(\Delta S_{\text {nal }}+\Delta S_{\text {um }}\right) $II. $A(\bar{i} \rightarrow A(\phi)$ : For this process entropy change decreases.III. Entropy unit...

At 300 K for the reaction. $A \rightarrow P$. The $\Delta S_p$ is $5 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$, What is the heat absorbed (in kJ $\mathrm{mol}^{-1}$ ) by the system?

If the standard enthalpy change $\left(\Delta_r H^{\circ}\right)$ for reaction $\mathrm{H}_2(\mathrm{~g})+\mathrm{Br}_2(l) \longrightarrow 2 \mathrm{HBr}(\mathrm{g})$ is -72.8 kJ , the standard enthalpy of formation $\left(\Delta_f H^{\circ...

If the standard enthalpy change $\left(\Delta_r H^{-}\right)$for a certain reaction at 298 K and constant pressure $-1860 \mathrm{~kJ} \mathrm{~mol}^{-1}$, the standard entropy change $\left(\Delta_{\text {sys }} \Omega^{\circ}\right)$ of t...

At 300 K the enthalpy change for the following reaction is $-2800 \mathrm{~kJ} \mathrm{~mol}^{-1}$.
\(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6(s)+6 \mathrm{O}_2(g) \longrightarrow 6 \mathrm{CO}_2(g)+6 \mathrm{H}_2 \mathrm{O}(l)\)
What is...

If the work done by 2 mol of an ideal gas during isothermal reversible expansion from 5 L to 50 L is -189.1 L atm at constant pressure, the temperature of the gas (in ${ }^{\circ} \mathrm{C}$ ) is

Use the data from table to estimate the enthalpy of formation of \(\mathrm{CH}_3 \mathrm{CHO}\).

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Identify the correct statements from the following.
I. At 0 K , the entropy of pure crystalline materials approach zero.
II. Entropy for the process, $$\mathrm{H}_2 \mathrm{O}(\mathrm{l}) \longrightarrow \mathrm{H}_2 \mathrm{O}(\mathrm{g})$...

State \(1 \rightleftharpoons\) State \(2 \rightleftharpoons\) State 3
$$\left(\begin{array}{l}T=300 \mathrm{~K} \\ p=15 \mathrm{bar} \\ 1 \mathrm{~mol}\end{array}\right)\left(\begin{array}{l}T=300 \mathrm{~K} \\ p=10 \mathrm{bar} \\ 1 \math...

Identify the reaction/process in which the entropy increases.

From the following plots, find the correct option.

Match the following.

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