Thermodynamics practice · Mixed difficulty

Assign the sign of work done (based on SI convention) in
the following chemical changes taking place against
external atmospheric pressure
I. $\mathrm{N}_2(g)+3 \mathrm{H}_2(g) \longrightarrow 2 \mathrm{NH}_3(g)$

II. $\mathrm{NH}_4 \mathrm{HS}(s) \longrightarrow \mathrm{NH}_3(g)+\mathrm{H}_2 \mathrm{~S}(g)$

III. $\mathrm{C}(\mathrm{s})+\mathrm{CO}_2(g) \longrightarrow 2 \mathrm{CO}(g)$

IV. $\mathrm{C}_2 \mathrm{H}_6(g)+3.5 \mathrm{O}_2(g) \longrightarrow 2 \mathrm{CO}_2(g)+3 \mathrm{H}_2 \mathrm{O}(l)$

At the given condition of $CH_4 - O_2$ fuel
cell the cell emf is 0.8 V and the
enthalpy of combustion of $C{H_4} \text{ (g)}$ is
-772 kJ/mol. The maximum efficiency of
the given fuel cell in the given condition
is :

The state of a gas can be described by quoting the relationship between

One mole of a non-ideal gas undergoes a change of state (2.0 atm,3.0 L,95 K)→(4.0 atm,5.0 L,245 K) with a change in internal energy, ∆U=30.0 L atm. The change in enthalpy (∆H) of the process in L atm is:

If water is formed from ${H^ + }$ions and$O{H^ - },$the heat of formation of water is :

The volume of $\mathrm{O}_2$ required to completely burn $52 \mathrm{~g}$ at Ethyne $\left(\mathrm{C}_2 \mathrm{H}_2\right)$ of STP is:

The entropy change in the conversion of one mole of liquid water at $373 \mathrm{~K}$ to vapour at the same temperature is: (Latent heat of vaporization of water, $\Delta H_{\text {vap }}=2.257 \mathrm{~kJ} / \mathrm{g}$ )

Which of the following is a highly corrosive salt?

The standard free energy change for a gaseous reaction at $27^\circ C\,\,\mathrm{ is }\,\,x\,k.cal.$ If equilibrium constant for a reaction is 100 and R is $2\,cal.{k^{ - 1}}.mo{l^{ - 1}}.$ Then $x$ is

To calculate the amount of work done in joules during reversible isothermal expansion of an ideal gas, the volume must be expressed in

Enthalpy of the reaction $\mathrm{Ag}^{+}(\mathrm{aq})+\mathrm{Br}^{-}(\mathrm{aq}) \rightarrow$ $\mathrm{AgBr}(\mathrm{s})$ is $-84.54 \mathrm{~kJ}.$ Magnitude of enthalpies of formation of $\mathrm{Ag}^{+}(\mathrm{aq})$ and $\mathrm{Br}^{-}(\mathrm{aq})$ is in $8:9$ ratio but their signs are opposite. Enthalpy of formation of $\mathrm{AgBr}$ is $-99.54 \mathrm{~kJ} / \mathrm{mol}.$ The magnitude of enthalpy of formation of $\mathrm{Ag}^{+}(\mathrm{aq})$ is

For which reaction from the following, $\Delta {S}$ will be maximum ?

Which of the following is/are intensive properties?

(I) Temperature

(II) Heat

(III) Density

(IV) Refractive index

For the reaction: $\mathrm{PCl}_{5(g)} \rightarrow \mathrm{PCl}_{3(g)}+\mathrm{Cl}_{2(g)}$, which one is true?

Enthalpy of neutralization of the reaction between $\mathrm{CH}_3 \mathrm{COOH} \text{(aq)}$ and $\mathrm{NaOH} \text{(aq)}$ is $-13.2 \mathrm{~kcal/eq}$ and that of the reaction between $\mathrm{H}_2 \mathrm{SO}_4(\mathrm{aq})$ and $\mathrm{KOH}(\mathrm{aq})$ is $-13.7 \mathrm{~kcal} / \mathrm{eq}.$ The enthalpy of dissociation of $\mathrm{CH}_3 \mathrm{COOH}(\mathrm{aq})$ is

One mole of $\mathrm{CH}_3 \mathrm{COOH}$ undergoes dimerization in vapour phase at $127^{\circ} \mathrm{C}$ as:

$2 \mathrm{CH}_3 \mathrm{COOH}(\mathrm{g}) \rightleftharpoons\left(\mathrm{CH}_3 \mathrm{COOH}\right)_2(\mathrm{~g})$

if dimer formation is due to two $\mathrm{H}$-bonds involved in dimer, each of $33 \mathrm{~kJ}$ stength and the degree of dimerisation of acetic acid $98.2 \%$. The change in standard entropy during dimerization is

2 moles of an ideal gas at ${27^0}C$ temperature is expanded reversibly from 2L to 20L. Find entropy change (R=2cal/mol K).

Given, $\mathrm{N}_2(\mathrm{g})+3 \mathrm{H}_2(\mathrm{g}) \rightarrow 2 \mathrm{NH}_3(\mathrm{g})$;
$\Delta_{\mathrm{r}} \mathrm{H}^{\circ}=-92.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$

What is the magnitude of standard enthalpy of formation of $\mathrm{NH}_3$ gas?

Which of the following statements is correct?

Two mole of an ideal gas is expanded isothermally and reversibly from 1 L to 10 L at 300 K. The enthalpy change (in kJ) for the process is