Thermodynamics practice · Medium

2.1 g of Fe combines with S evolving 3.77 kJ. The heat of formation of FeS in kJ/mole is

In which of the given reactions, $\Delta {H} > \Delta {U}$ ?

Condition for spontaneity in an isothermal
process is

(A): The heat absorbed during isothermal expansion of an ideal gas against vacuum is zero.

(R) : The volume occupied by the molecules is zero.

Reaction

1. $\mathrm{C}+\mathrm{O}_2 \rightarrow \mathrm{CO}_2$ $\quad$ ; $\Delta \mathrm{G}=-380 \mathrm{~KJ}$

$\text { 2. } 4 \mathrm{Al}+3 \mathrm{O}_2 \rightarrow 2 \mathrm{Al}_2 \mathrm{O}_3 \quad ; \Delta \mathrm{G}=-2250 \mathrm{~KJ}$

Reduction of $\mathrm{Al}_2 \mathrm{O}_3$ in presence of carbon is possible or not ?

Three moles of an ideal gas are expanded isothermally from a volume of $300 \mathrm{~cm}^3$ to $2.5 \mathrm{~L}$ at $300 \mathrm{~K}$ against a pressure of $1.9 \mathrm{~atm}$. The work done in joules is

For a specific work, on an average a person requires $5616 \mathrm{~kJ}$ of energy. How many kilograms of glucose must be consumed if all the required energy has to be derived from glucose only? $\Delta H$ for combustion of glucose is $-2808 \mathrm{~kJ} \mathrm{~mol}^{-1}.$

Consider following statements:
(a) The absolute value of internal energy cannot be
evaluated.
(b) Entropy is a state function and extensive
property
(c) Temperature is an extensive property
(d) The standard enthalpy of formation of an element $\left(\Delta \mathrm{H}_{\mathrm{f}}\right)$ is always considered to be zero

(e) For an adiabatic process $\Delta S>0$
wrong statements are :

The heat evolved during neutralisation is maximum in the reaction of :

Assertion :- At constant temperature $0^{\circ} \mathrm{C}$ and $1 \mathrm{~atm}$, the change $\mathrm{H}_2 \mathrm{O}(\mathrm{s}) \rightarrow \mathrm{H}_2 \mathrm{O}(\ell), \Delta \mathrm{H}$ and $\Delta \mathrm{E}$ both are zero.

Reason :- During isothermal process $\mathrm{H}$ and $\mathrm{E}$ both remains constant.

The enthalpies of elements in their standard states are taken as zero. The enthalpy of formation of a compound

Predict which of the following reactions has a negative entropy change?

I. ${CH}_4({~g})+2 {O}_2({~g}) \rightarrow {CO}_2({~g})+2 {H}_2 {O}(\ell)$

II. ${Ag}_{({aq})}^{+}+{Cl}_{({aq})}^{-} \rightarrow {AgCl}({s})$

III. ${H}_2({~g}) \rightarrow 2 {H}({g})$

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

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?

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

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