Thermodynamics practice · Medium

The entropy change (in cal $\mathrm{K}^{-1} \mathrm{~mol}^{-1}$ ) when one mole of an ideal gas at $27^{\circ} \mathrm{C}$ is expanded reversibly from $1 \ell$ to $10 \mathrm{~I}$ is

1 mole of an ideal gas at 25℃ is subjected to expand reversibly ten times of its initial volume. The change in entropy of expansion is:

Calculate the Gibbs energy change when 1 mole of ${NaCl}$ is dissolved in water at $298 {~K}$. Given,

(a) Lattice energy of ${NaCl}=778 {~kJ} {~mol}^{-1}$.

(b) Hydration energy of ${NaCl}=774.3 {~kJ} {~mol}^{-1}$.

(c) Entropy change at $298 {~K}=43 {~J} {~mol}^{-1}$.

In which case of mixing of a strong acid and a base each of 1N concentration, temperature increase is highest?

When $100 \mathrm{~ml}$ of $1.0 \mathrm{~M} \mathrm{~HCl}$ was mixed with $100 \mathrm{~ml}$ of $1.0 \mathrm{~M} \mathrm{~NaOH}$ in an insulated beaker at constant pressure, a temperature increase of $5.8^{\circ} \mathrm{C}$ was measured for the beaker and its constants. If the enthalpy of neutralization of a strong acid with a strong base is $-58.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$. the calorimeter constant in $\left(\mathrm{kJ} \mathrm{k}^{-1}\right)$ is ___
(Given: Heat capacity of solution is $4.2 \mathrm{~J} \mathrm{~g}^{-1} \mathrm{k}^{-1}$ and density of solution is $1 \mathrm{~g} \mathrm{~mL}^{-1}$)

For the reaction, $\mathrm{N}_2+3 \mathrm{H}_2 \rightleftharpoons 2 \mathrm{NH}_3 ; \Delta \mathrm{H}=$ ?

Which one of the following is used to remove most of plutonium from spent nuclear fuel?

Enthalpies of formation of $CO\left( g \right),\,\,\,C{O_2}\left( g \right),\,\,\,{N_2}O\left( g \right)$ and ${N_2}{O_4}\left( g \right)$ are –110, –393, 81 and 9.7 KJ/mol respectively. Find the value of ${\Delta _r}H$ for the reaction ${N_2}{O_4}\left( g \right) + 3CO\left( g \right) \to {N_2}O\left( g \right) + 3C{O_2}\left( g \right)$

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

Assertion :- The value of specific heat at constant pressure is more than that at constant
volume.

Reason :- The energy required to raise temperature by a unit at constant pressure is
greater because some amount of heat is used in doing work.

The standard heat of combustion of propane is $-2220.1 \mathrm{~kJ} / \mathrm{mol}.$ The standard heat of vaporization of liquid water is $44 \mathrm{~kJ} / \mathrm{mol}.$ What is the $\Delta H^{\circ}$ of the following reaction?

$\mathrm{C}_3 \mathrm{H}_8(\mathrm{g})+5 \mathrm{O}_2(\mathrm{g}) \rightarrow 3 \mathrm{CO}_2(\mathrm{g})+4 \mathrm{H}_2 \mathrm{O}(\mathrm{g})$

The entropy change accompanying the transfer of $12,000 \mathrm{~J}$ of heat from a body ${A}$ at $327^{\circ} \mathrm{C}$ to a body $B$ at $127^{\circ} \mathrm{C}$ is

The ratio $K_p$ to $K_c$ of a reaction is $24.63 \mathrm{~L ~atm ~mol}^{-1}$ at $27^\circ \mathrm{C}$. If heat of reaction at constant pressure is 98.8 kcal, what is the heat of reaction (in kcal) at constant volume?

The least random state of ${H_2}O$ is

$\mathrm{NH}_4 \mathrm{Cl}(s)+\mathrm{H}_2 \mathrm{O}(a q) \rightleftharpoons \mathrm{NH}_4 \mathrm{Cl}(a q)$

Due to dissolution of ammonium chloride in $\mathrm{H}_2 \mathrm{O}$, temperature falls rapidly. Thus,

The correct descending order of the heat liberated (in $\mathrm{kJ}$ ) during the neutralisation of the acids $\mathrm{CH}_3 \mathrm{COOH}(W), \mathrm{HF}(X), \mathrm{HCOOH}(Y)$ and $H C N(Z)$ under indentical conditions $\left(K_a\right.$ of $\mathrm{CH}_3 \mathrm{COOH}=1.8 \times 10^{-5}, {H C O O H}=1.8 \times 10^{-4}$, $\mathrm{HCN}={4 . 9} \times 10^{-10}$ and $\mathrm{HF}=3.2 \times 10^{-4}$ ) is

The standard enthalpy of formation $\left(\Delta_f {H}^{\circ}{ }_{298}\right)$ for methane, ${CH}_4$ is $-74.9 {~kJ} {~mol}^{-1}$. In order to calculate the average energy given out in the formation of a ${C}-{H}$ bond from this it is necessary to know which one of the following?

Spontaneous adsorption of a gas on solid surface is an
exothermic process because

Assertion : For a reaction

$2 {NH}_3({~g}) \longrightarrow {N}_2({~g})+3 {H}_2({~g}) ; \Delta H>\Delta E$

Reason : Enthalpy change is always greater than internal energy change.

In a process, $701 \mathrm{~J}$ of heat is absorbed by a system and $394 \mathrm{~J}$ of work is done by the system. What is the change in internal energy for the process?

Based on following thermochemical reaction:

$\begin{aligned} & {H}_2 {O}(\mathrm{g})+{C}(\mathrm{s}) \rightarrow {CO}(\mathrm{g})+{H}_2(\mathrm{g}) ; \Delta {H}=131 \mathrm{~KJ} \\ & {CO}(\mathrm{g})+\frac{1}{2} {O}_2(\mathrm{g}) \rightarrow {CO}_2(\mathrm{g}) ; \Delta {H}=-282 \mathrm{~KJ} \\ & {H}_2(\mathrm{g})+\frac{1}{2} {O}_2(\mathrm{g}) \rightarrow {H}_2 {O}(\mathrm{g}) ; \Delta {H}=-242 \mathrm{~KJ} \\ & {C}(\mathrm{s})+{O}_2(\mathrm{g}) \rightarrow {CO}_2(\mathrm{g}) ; \Delta {H}=x \mathrm{~KJ} \end{aligned}$

The value of $x$ will be

${C}+\frac{1}{2} {O}_2 \rightarrow {CO} ; \Delta {H}=-42 \mathrm{~kJ}$

${CO}+\frac{1}{2} {O}_2 \rightarrow {CO}_2 ; \Delta {H}=-24 \mathrm{~kJ}$

The heat of formation of ${CO}_2$ is

The heat change taking place during the reaction $\;{\mathrm{H}_2}\mathrm{O}\left( l \right)$$\to {\mathrm{H}_2}\mathrm{O(g)}$ is: [Given,$\Delta {H_f}$ of ${\mathrm{H}_2}\mathrm{O}(g)$ = -57 kcal, $\Delta {H_f} = {\mathrm{H}_2}\mathrm{O}\left( l \right)$ = -68.3 kcal]

0.75 mole of an ideal gas expands at $27^{\circ} \mathrm{C}$ from $15 \mathrm{~L}$ to $25 \mathrm{~L}$, then maximum work done is

Calculate the standard enthalpy of solution of $\mathrm{AgCl}(\mathrm{s})$ in water $\Delta \mathrm{H}^\circ_{\mathrm{f}}(\mathrm{AgCl}, \mathrm{s})=-127.07 \mathrm{~kJ} \mathrm{~mol}^{-1}$, $\Delta \mathrm{H^\circ_f}\left(\mathrm{Ag}^{+}, \mathrm{aq}\right)=105.58 \mathrm{~kJ} \mathrm{~mol}^{-1}, \Delta \mathrm{H}^\circ_\mathrm{f}\left(\mathrm{Cl}^{-}, \mathrm{aq}\right)=-167.35 \mathrm{~kJ} \mathrm{~mol}^{-1}$.

A sample of $100 {~g} {H}_2 \mathrm{O}$ is slowly heated from $27^{\circ} {C}$ to $87^{\circ} {C}$. Calculate the change in entropy during heating (Specific heat of water $=4200 {~J} / {kg}-{K}$ ).

Assertion (A): The difference between $\Delta H$ and $\Delta U$ is not significant for systems consisting of only solids or liquids.
Reason (R): Solids and liquids do not suffer any significant volume changes upon heating.

Assertion: When ideal gas expand from $P_1, V_1, T_1$ to $P_2, V_2, T_2$ in multiple steps, work done is high where number of steps are high.
Reason: Work is path function.

For a reaction ${Y}_2{O}_4(\ell) \longrightarrow 2 {YO}_2(\mathrm{g})$

$\Delta {E}=2.1 \mathrm{~KCal}, \Delta {S}=20 \mathrm{~calK}^{-1}$ at $300 \mathrm{~K}, \Delta {G}$ will be:

The enthalpies of formation of $\mathrm{C}_2 \mathrm{H}_2(\mathrm{~g})$ and $\mathrm{C}_6 \mathrm{H}_6(\mathrm{~g})$ at $298 \mathrm{~K}$ are 230 and $85 \mathrm{~kJ} / \mathrm{mol}$ respectively. The enthalpy change for the reaction is