Embibe Experts Solutions for Chapter: Thermodynamics, Exercise 4: EXERCISE-III (Analytical Questions)

For a reversible process at $\mathrm{T}=300\mathrm{K},$ the volume is increased from ${\mathrm{V}}_{\mathrm{i}}=1\mathrm{L}$ to ${\mathrm{V}}_{\mathrm{f}}=10\mathrm{L}$. Calculate $\mathrm{\Delta H}$ if the process is isothermal:

The entropy change involved in the isothermal reversible expansion of$2 \mathrm{moles}$ of an ideal gas from a volume of $10 {\mathrm{dm}}^3$ to a volume of $100 {\mathrm{dm}}^3$ at $27°\mathrm{C}$ is:

The conversion $\mathrm{A}$ to $\mathrm{B}$ is carried out by the following path :

Given : ${\mathrm{\Delta S}}_{(\mathrm{A}\to \mathrm{C})}=50$ $\mathrm{e}.\mathrm{u}.$

${\mathrm{\Delta S}}_{(\mathrm{C}\to \mathrm{D})}=30$ $\mathrm{e}.\mathrm{u}.$, ${\mathrm{\Delta S}}_{(\mathrm{B}\to \mathrm{D})}=20$ $\mathrm{e}.\mathrm{u}.$

where $\mathrm{e}.\mathrm{u}.$ is entropy unit then ${\mathrm{\Delta S}}_{(\mathrm{A}\to \mathrm{B})}$ is

In conversion of lime-stone to lime, ${\mathrm{CaCO}}_{3\left(\mathrm{s}\right)}⟶{\mathrm{CaO}}_{\left(\mathrm{s}\right)}+{\mathrm{CO}}_{2\left(\mathrm{g}\right)}$ the values $△\mathrm{H}°$ and $△\mathrm{S}°$ are $179.1 \mathrm{kJ} {\mathrm{mol}}^{-1}$ and $160.2 \mathrm{J} {\mathrm{K}}^{-1}-{\mathrm{mol}}^{-1}$ respectively at $298 \mathrm{K}$ and $1 \mathrm{bar}$. Assuming that $△\mathrm{H}°$ and $△\mathrm{S}°$ do not change with temperature, temperature above which conversion of lime stone to lime will be spontaneous is :

Identify the correct statement regarding a sponateous process :-

For complete combustion of ethanol, ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)⟶2{\mathrm{CO}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$, the amount of heat produced as measured in bomb calorimeter, is $1364.47 \mathrm{kJ} {\mathrm{mol}}^{-1}$ at $25°\mathrm{C}$. Assuming ideality the enthalpy of combustion, ${\mathrm{\Delta }}_{\mathrm{C}}\mathrm{H}$ reaction will be :

$\left(\mathrm{R}=8.314 \mathrm{kJ} {\mathrm{mol}}^{-1}\right)$

If the bond dissociation energies of$\mathrm{XY}, {\mathrm{X}}_2 \& {\mathrm{Y}}_2$(all diatomic molecules) are in the ratio $1:1:0.5$ and $∆{\mathrm{H}}_{\mathrm{f}}$ for the formation of $\mathrm{XY}$ is $-200 \mathrm{kJ} {\mathrm{mol}}^{-1}$, the bond dissociation energy of ${\mathrm{X}}_{2 }$will be

Oxidising power of chlorine in an aqueous solution can be determined by the parameters indicated below:

$\frac{1}{2}{\mathrm{Cl}}_2\left(\mathrm{g}\right)\stackrel{\frac{1}{2}{\mathrm{\Delta }}_{\mathrm{dis}}{\mathrm{H}}^{\ominus }}{⟶}\mathrm{Cl}\left(\mathrm{g}\right)\stackrel{{\mathrm{\Delta }}_{\mathrm{eg}}{\mathrm{H}}^{\ominus }}{⟶}{\mathrm{Cl}}^{-}\left(\mathrm{g}\right)\stackrel{{\mathrm{\Delta }}_{\mathrm{hyd}}{\mathrm{H}}^{\ominus }}{⟶}{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)$

The energy involved in the conversion of

$\frac{1}{2}{\mathrm{Cl}}_2\left(\mathrm{g}\right)$ to ${\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)$

(using the data, ${\mathrm{\Delta }}_{\mathrm{diss}}{\mathrm{H}}_{{\mathrm{Cl}}_2}^{\ominus }=240 \mathrm{kJ} {\mathrm{mol}}^{-1}$, ${\mathrm{\Delta }}_{\mathrm{eg}}{\mathrm{H}}_{\mathrm{Cl}}^{\ominus }=-349 \mathrm{kJ} {\mathrm{mol}}^{-1}, {\mathrm{\Delta }}_{\mathrm{hyd}}{\mathrm{H}}_{{\mathrm{Cl}}^{-}}^{\ominus }=-381 \mathrm{kJ} {\mathrm{mol}}^{-1}$) will be: