Thermodynamics practice · Mixed difficulty

Which is the correct Gibb's Helmholtz
equation?

A gas is allowed to expand in an insulated container against a constant external pressure of 4 atm from the initial volume of 1.8 L to a final volume of 5.2 L. The change in internal energy of the gas is

Geological conditions are sometimes so extreme that quantities neglected in normal laboratory experiments take on an overriding importance. For example, consider the formation of diamond under geophysically typical conditions. The density of graphite is $2.4 \mathrm{~g} / \mathrm{cm}^3$ and that of diamond is $3.6 \, \mathrm{g} / \mathrm{cm}^3$ at a certain temperature and $500 \mathrm{~kbar}.$ By how much does $\Delta U_{\text {trans}}$ differs from $\Delta H_{\text {trans}}$ for the graphite to diamond transition?

$16 \mathrm{~gm} \, {O}_2$ is expanded reversibly at $300 \mathrm{~K}$ temperature from $5 \mathrm{~dm}^3$ to $25 \mathrm{~dm}^3$ then find out ${W}$ and ${q}$ (in cal)

Consider the following thermochemical equation $2 \mathrm{H}_2(\mathrm{g})+\mathrm{O}_2(\mathrm{g}) \rightarrow 2 \mathrm{H}_2 \mathrm{O}(\mathrm{g}) \, \Delta \mathrm{H}^{\circ}=-470 \mathrm{~kJ}$ If standard enthalpy of vaporisation of $\mathrm{H}_2 \mathrm{O}(\ell)$ is $50 \mathrm{~kJ} / \mathrm{mole}$, then find calorific value of $\mathrm{H}_2(\mathrm{g})$ in standard conditions:

Two moles of an ideal gas undergo reversible isothermal expansion from $2.303 \mathrm{~L}$ to $23.03 \mathrm{~L}$ at $27^{\circ} \mathrm{C}$. The change in entropy is: $\left[\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1}\right.$ $\mathrm{mol}^{-1}$]

STATEMENT-1 : There cannot be chemical equilibrium in an open system.

STATEMENT-2 : There is no fixed mass in an open system.

Statement I Based on the following thermochemical
reactions;
$\mathrm{HF}(a q)+\mathrm{OH}^{-}(a q) \longrightarrow \mathrm{H}_2 \mathrm{O}(l)+\mathrm{F}^{-}(a q) ; \Delta H^{\circ}=-16.4 \mathrm{~k~cal}$

$\mathrm{H}^{+}(a q)+\mathrm{OH}^{-}(a q) \longrightarrow \mathrm{H}_2 \mathrm{O}(l), \Delta H^{\circ}=-13.7 \mathrm{~k~cal}$

Ionisation of $\mathrm{HF}(\mathrm{aq})$ is an exothermic reaction.

Statement II Enthalpy decrease in hydration of $\mathrm{H}^{+}(a q)$ and $\mathrm{F}^{-}(a q)$ exceeds the ionisation enthalpy of $\mathrm{HF}(a q)$.

The enthalpy change is negative for :

Assertion :- Catalyst changes Gibbs free energy of system.

Reason :- Catalyst changes preexpotential factor of a chemical reaction.

In the exothermic reaction, the enthalpy of
reaction is always:

STATEMENT-1: The expansion of a gas into an evacuated space takes place non-spontaneously.

STATEMENT-2 : A process in which all steps cannot be retraced by themselves is called a spontaneous process.

10 moles of an ideal gas compressed from $100\, \mathrm{~L}$ to $10 \,\mathrm{~L}$ reversibly at constant temperature of $27^{\circ} \mathrm{C}$. The entropy change during the process is ( $R=$ Universal gas constant)

Identify the correct statement for change of Gibb’s energy for a system ($\Delta {G_{\mathrm{system}}}$) at constant temperature and pressure:

When $1 \mathrm{~g}$ equivalent of strong acid reacts with strong base, the heat released is $13.5 \mathrm{~kcal}.$ When $1 \mathrm{~g}$ equivalent $\mathrm{H}_2 \mathrm{A}$ is completely neutralized against strong base, $13 \mathrm{~kcal}$ is released. When $1 \mathrm{~g}$ equivalent $\mathrm{B}(\mathrm{OH})_2$ is completely neutralized against strong acid, $10 \mathrm{~kcal}$ heat is released. What is the enthalpy change when 1 mole of $\mathrm{H}_2 \mathrm{A}$ is completely neutralized by $\mathrm{B}(\mathrm{OH})_2?$

$\begin{aligned} & \text {If } \mathrm{H}_2+1 / 2 \mathrm{O}_2 \longrightarrow \mathrm{H}_2 \mathrm{O}, \Delta \mathrm{H}=-68 \mathrm{~kcal} \\ & \mathrm{K}+\mathrm{H}_2 \mathrm{O}+\text {water} \longrightarrow \mathrm{KOH}(\mathrm{aq})+1 / 2 \mathrm{H}_2, \Delta \mathrm{H}=-48 \mathrm{~kcal} \\ & \mathrm{KOH}+\text {water} \longrightarrow \mathrm{KOH}(\mathrm{aq}), \Delta \mathrm{H}=-14 \mathrm{~kcal} \end{aligned}$

Find the heat of formation of $\mathrm{KOH}$.

The bond dissociation energies for $Cl_2, I_2$ and
$ICl$ are 242.3, 151 and 211.3 kJ/mol
respectively. The enthalpy of sublimation of
iodine is 62.8 kJ/mol. What is the standard
enthalpy of formation of $ICl \text{(g)}?$

Which of the following statements is incorrect?

Taking each reactant in 1:1 molar ratio, enthalpy changes are $\Delta H_1^\circ$ and $\Delta H_2^\circ$ in the following reactions.

$\begin{aligned} & \mathrm{Ca}(\mathrm{OH})_2+\mathrm{HCl} \longrightarrow \mathrm{Ca}(\mathrm{OH}) \mathrm{Cl}+\mathrm{H}_2 \mathrm{O} ; \Delta \mathrm{H}_1{ }^{\circ} \\ & \mathrm{Ca}(\mathrm{OH}) \mathrm{Cl}+\mathrm{HCl} \longrightarrow \mathrm{CaCl}_2+\mathrm{H}_2 \mathrm{O} ; \Delta \mathrm{H}_2{ }^{\circ} \end{aligned}$

$\Delta H_{1^{\circ}}$ and $\Delta H_{2^{\circ}}$ are (in kcal)

Which one among the following pairs does not
represent example for intensive property?

Which among the following is an extensive property?

The change of enthalpy of a chemical reaction is the same whether the reaction takes place in one step or in several steps". This law was presented by

In which one of the following sets, all the properties belong to same category (all extensive or all intensive)?

Which one among the following is the correct option for right relationship between ${C_p}\mathrm{ and }{C_v}$ for one mole of ideal gas?

The heats of combustion of carbon and carbon moxoide are – 393.5 and $- 283.5\,kJ\,mo{l^{ - 1}}$, respectively. The heat of formation (in kJ) of carbon monoxide per mole is

Given that $\Delta H_f(H)=218 \mathrm{~kJ} / \mathrm{mol}$, express the $\mathrm{H}-\mathrm{H}$ bond energy in $\mathrm{k ~cal} / \mathrm{mol}$.

The reaction, $MgO(s) + C(s) \to Mg(s) + CO(g)$, for which ${\Delta _r}{H^ \circ } = + 491.1kJ\mathrm{ }mo{l^{ - 1}}$ and ${\Delta _r}{S^ \circ } = 198.0J{K^{ - 1}}mo{l^{ - 1}}$ , is not feasible at 298 K. Temperature above which reaction will be feasible is

A system undergoes a two-step process. In step 1, $15 \mathrm{~J}$ of work is done on the system as its internal energy increases by a total of $30 \mathrm{~J}.$ In step 2, at constant volume, the system decreases its internal energy by $20 \mathrm{~J}.$ Which statement is true about these changes?

A system absorbs 10 kJ of heat and does 4 kJ of work. The internal energy of the system

For which among the following reactions,
change in entropy is less than zero