Cell reaction is spontaneous when

• $∆\mathrm{G}°$ is negative

• $∆\mathrm{G}°$ is positive

• $∆{\mathrm{E}}_{\mathrm{red}}^{°}$ is positive

• $∆{\mathrm{E}}_{\mathrm{red}}^{°}$ is negative

At 27°C latent heat of fusion of a compound is 2930 J/ mol, then entropy change is

• 9.77 J/mol-K

• 10.77 J/ mol-K

• 9.07 J/ mol-K

• 0.977 J/ mol-K

For the reaction,

C₂H₅OH (l) + 3O₂ (g) → 2CO₂ (g) + 3H₂O (l)

which one is true?

• $∆\mathrm{H} = ∆\mathrm{E} - \mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} + \mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} + 2\mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} - 2\mathrm{RT}$

What is the entropy change (in JK^-1 mol^-1) when one mole of ice is converted into water at 0°C? (The enthalpy change for the conversion of ice to liquid water is 6.0 kJ mol^-1 at 0°C).

• 20.13

• 2.013

• 2.198

• 21.98

The molar heat capacity (C) of water at constant pressure, is 75 JK^-1 mol^-1. When 1.0 kJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is

• 1.2 K

• 2.4 K

• 4.8 K

• 6.6 K

Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction?

• Endothermic and decreasing disorder

• Exothermic and increasing disorder

• Endothermic and increasing disorder

• Exothermic and decreasing disorder

Identify the correct statement for change of Gibbs energy for a system ($∆$G_system) at constant temperature and pressure

• If $∆$G_system = 0, the system has attained equilibrium

• If $∆$G_system = 0, the system is still moving in a particular direction

• If $∆$G_system = 0, the process is not spontaneous

• If $∆$G_system = 0, the process is spontaneous

458.

To which of the following determinations of heat, Hess's law is used?

• Heat of chemical reaction

• Heat of formation

• Heat of bond formation

• All of the above

C₂H₂ + $\frac{5}{2}{\mathrm{O}}_2$ → 2CO₂ + H₂O ; ΔH = -310 Kcal

C + O₂ → CO₂ ; ΔH = -94 Kcal

H₂ + $\frac{1}{2}{\mathrm{O}}_2$  →   H₂O ; ΔH = -68 Kcal

On the basis of the above equations, ΔH_f (enthalpy of formation) of C₂H₂ ,will be

• -148 Kcal

• +54 Kcal

• -54 Kcal

• +80 Kcal

I₂(s) $\rightleftharpoons$I₂(g) ΔH= + 40Kcal, ΔS= 80cal. The sublimation point of I₂(s) will be

• 100°C

• 127°C

• 227°C

• 500°C