Entropy decreases during:

1. Crystallization of sucrose from solution

2. Rusting of iron

3. Melting of ice

4. Vaporization of camphor

At a temperature of 300K, what is the entropy change for the reaction given below?

2H₂ (g) + O₂ (g) $\to$2H₂O(l)

Standard entropies of H₂ (g), O₂(g) and H₂O(l) are 126.6, 201.20 and 68.0 JK^-1mol^-1 respectively.

1. -318.4 JK^-1mol^-1                           

2. 318.4 JK^-1mol^-1 

3. 31.84 JK^-1mol^-1                             

4. None of the above

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)

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

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)

$∆{\mathrm{H}}_{\mathrm{f}}^0$ (298K) of methanol is given by the chemical equation -

1. C(diamond)+$\frac{1}{2}{O}_2$+2H₂$\to$CH₃OH

2. CH₄+$\frac{1}{2}{O}_2$$\to$CH₃OH

3. CO+2H₂$\to$CH₃OH

4. C(graphite)+$\frac{1}{2}{O}_2$+2H₂$\to$CH₃OH

The difference in $∆H$ $and$ $∆U$ for combustion of benzoic acid at 300 K is equal to-

1. -1.247 kJ

2. +1.247 kJ

3. -1.247 J

4. +1.247 J

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

An ideal gas expands isothermally from ${10}^{-3}{m}^3 to {10}^{-2} m^3$ at 300 K against a constant pressure of ${10}^5 N{m}^{-2}$. The work done by  the gas is:

The maximum work done in expanding 16g ${\mathrm{O}}_2$ isothermally at 300 K and occupying a volume of 5 dm³ until the volume becomes 25 dm³ is-

1. –2.01$\times {10}^3$ J

2. 2.01×${10}^{-3}$ J

3. +2.81$\times {10}^3$ J

4. +2.01$\times {10}^{-6}$J