When 4 g of iron is burnt to ferric oxide at a constant pressure, 29.28 kJ of heat is evolved.

The enthalpy of formation of ferric oxide will be-

(At. mass of Fe = 56) ?

1. $-$81.98 kJ

2. $-$ 819.8 kJ

3. $-$ 40.99 kJ

4.  +819.8 kJ

Hydrolysis of sucrose is given by the following reaction

Sucrose + H₂O $\rightleftharpoons$ Glucose + Fructose

If the equilibrium constant (K_c) is 2$\times$10¹³ at 300 K, the value of ${∆}_r{G}^{⊝}$ at the same temperature will be:

1. 8.314 J mol^–1 K^–1$\times$300 K$\times$ln (2$\times$10¹³)

2. 8.314 J mol^–1 K^–1$\times$300 K$\times$ln (3$\times$10¹³)

3. –8.314 J mol^–1 K^–1$\times$300 K$\times$ln (4$\times$10¹³)

4. –8.314 J mol^–1 K^–1$\times$300 K$\times$ln (2$\times$10¹³)

The enthalpies of formation of Al₂O₃ and Cr₂O₃ are – 1596 kJ and – 1134 kJ, respectively. ∆H for the reaction 2Al + Cr₂O₃ → 2Cr + Al₂O₃ is -

Assume each reaction is carried out in an open container. For which of the following reactions will $∆\mathrm{H\; be\; equal\; to }∆\mathrm{U}?$

1. ${\mathrm{PCl}}_3\left(\mathrm{g}\right)$ $\to {\mathrm{PCl}}_3\left(\mathrm{g}\right)$ $+{\mathrm{Cl}}_2\left(\mathrm{g}\right)$ $$

2. $2\mathrm{CO}\left(\mathrm{g}\right)$ $+{\mathrm{O}}_2\left(\mathrm{g}\right)$ $\to 2{\mathrm{CO}}_2\left(\mathrm{g}\right)$ $$

3. ${\mathrm{H}}_2\left(\mathrm{g}\right)$ $+{\mathrm{Br}}_2\left(\mathrm{g}\right)$ $\to 2\mathrm{HBr}\left(\mathrm{g}\right)$

4. $\mathrm{C}\left(\mathrm{s}\right)$ $+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$ $\to 2{\mathrm{H}}_2\left(\mathrm{g}\right)$ $+{\mathrm{CO}}_2\left(\mathrm{g}\right)\hspace{0.17em}$

Which of the following is not an endothermic reaction?

1. Combustion of methane

2. Decomposition of water

3. Dehydrogenation of ethane or ethylene

4. Conversion of graphite to diamond

For the following given equations and $∆\mathrm{H}°$ values, determine the enthalpy of reaction at 298 K for the reaction-

C₂H₄(g) + 6F₂(g) $\to$ 2CF₄(g) + 4HF(g)

H₂(g) + F₂(g) $\to$ 2HF(g)       $∆{\mathrm{H}}_1^{°}$= -537 kJ

C(s) + 2F₂(g) $\to$CF₄(g)         $∆{\mathrm{H}}_2^{°}$=-680 kJ

2C(s) + 2H₂(g) $\to$C₂H₄(g)    $∆{\mathrm{H}}_3^{°}$= 52 kJ

1. -1165 

2. -2486

3. +1165

4. +2486

Change in entropy is negative for:

1. Bromine (l)$\to$Bromine(g)

2. C(s) + H₂O(g) $\to$CO(g) + H₂(g)

3. N₂(g,10 atm)$\to$N₂(g,1 atm) 

4. Fe ( 1mol, 400 K) $\to$ Fe( 1mol, 300 K)

Entropy decreases during:

1. Crystallization of sucrose from solution

2. Rusting of iron

3. Melting of ice

4. Vaporization of camphor

A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 37.0ºC. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be-
(R = 8.314 J/mol K) (ln 7.5 = 2.01)

For the reaction, $2C{}^{}\to C{}^{}$, the value of ∆H and ∆S  are respectively -

1. $∆\mathrm{H}=0$ $,$ $∆\mathrm{S}=-\mathrm{ve}$

2. $∆\mathrm{H}=0$ $,$ $∆\mathrm{S}=0$

3. $∆\mathrm{H}=$ $-\mathrm{ve}$ $,$ $∆\mathrm{S}$ $=$ $-\mathrm{ve}$

4. $∆\mathrm{H}=$ $+\mathrm{ve}$ $,$ $∆\mathrm{S}=$ $+\mathrm{ve}$