The heat of combustion of carbon to CO₂ is -393.5 kJ/mol. The heat released upon the

formation of 35.2 g of CO₂ from carbon and oxygen gas is

1. -315 kJ               

2. +315 kJ             

3. -630 kJ                 

4. -3.15 kJ

For the reaction, X₂O₄(l) $\to$2XO₂(g)

$∆$U = 2.1 kcal, $∆$S = 20 cal K^-1 at 300 K. Hence, $∆$G is

1. 2.7 kcal

2. -2.7 kcal

3. 9.3 kcal

4. -9.3 kcal

In which of the following reactions, standard reaction entropy changes ($∆$S$°$) is positive

and standard Gibbs energy change ($∆$G$°$) decreases sharply with increasing

temperature?

1. C(graphite) + 1/2 O₂(g) $\to$CO(g)

2. CO(g) + 1/2 O₂(g)$\to$CO₂(g)

3. Mg(s) + 1/2 O₂(g) $\to$MgO(s)

4. 1/2 C (graphite) + 1/2 O₂(g) $\to$1/2 CO₂(g)

The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0 °C is:

1. 10.52 cal/(mol K)

2. 21.04 cal/(mol K)

3. 5.260 cal/(mol K)

4. 0.526 cal/(mol K)

The standard enthalpy of vaporisation $∆$_vapH$°$ for water at 100$°$C is 40.66 kJ mol^-1. The

internal energy of vaporisation of water at 100$°$C (in kJ mol^-1) is- 

(Assume water vapour to behave like an ideal gas)

1. +37.56                   

2. -43.76

3. +43.76                   

4. +40.66

If the enthalpy change for the transition of liquid water to steam is 30 kJ mol^-1 at 27°C,

the entropy change for the process would be

1. 1.0 J mol^-1 K^-1

2. 0.1 J mol^-1K^-1

3. 100 J mol^-1K^-1

4. 10 J mol^-1K^-1

Which of the following options correctly describes the free expansion of an ideal gas under adiabatic conditions?
1. \(\mathrm{{q} \neq 0, ~~ \Delta {T}=0, ~~ {~W}=0} \)
2. \(\mathrm{{q}=0, ~~ \Delta {T}=0, ~~ {~W}=0} \)
3. \(\mathrm{{q}=0, ~~ \Delta {T}<0, ~~ {~W} \neq 0} \)
4. \(\mathrm{{q}=0, ~~ \Delta {T} \neq 0, ~~ {~W}=0} \)

Enthalpy change for the reaction,

 4H(g) $\to$2H₂(g) is -869.6 kJ

The dissociation energy of H-H bond is

1. -869.6 kJ                 

2. + 434.8 kJ

3. +217.4 kJ                 

4. -434.8 kJ

Standard entropies of X₂, Y₂ and XY₃ are 60, 40 and 50 J K^-1mol^-1 respectively. For the reaction

$\frac{1}{2}{\mathrm{X}}_2 + \frac{3}{2}{\mathrm{Y}}_2 \stackrel{ }{\rightleftharpoons }{\mathrm{XY}}_3; ∆\mathrm{H} =-30 \mathrm{kJ},$
$\mathrm{to} \mathrm{be} \mathrm{at} \mathrm{equilibrium}, \mathrm{the} \mathrm{temperature} \mathrm{should} \mathrm{be}$
$1. 750\mathrm{K}$
$2. 1000\mathrm{K}$
$3. 1250\mathrm{K}$
$4. 500\mathrm{K}$

Given the following bond energies:

Based on the data given above, enthalpy change for the following reaction will be:
 

1. 1523.6 kJ mol^-1

2. -243.6 kJ mol^-1

3. -120.0 kJ mol^-1

4. 553.0 kJ mol^-1