Based on the first law of thermodynamics, which one of the following is correct?

• For an isochoric process = ΔE = - q

• For an adiabatic process = ΔE =-w

• For an isothermal process = q = + w

• For a cyclic process q = - w

512.

For the reversible reaction, A (s) + B (g) $\rightleftharpoons$ C (g) + D (g), $∆\mathrm{G}°$ = -350 kJ, which one of the following statements is true?

• The reaction is thermodynamically non-feasible

• The entropy change is negative

• Equilibrium constant is greater than one

• The reaction should be instantaneous

The value of entropy of solar system is

• Increasing

• decreasing

• constant

• zero

Which of the following statements is true?

• The total entropy of the universe is continuously decreasing

• The total energy of the universe is continuously decreasing

• The total energy of the universe remains constant

• The total entropy of the universe remains constant

A gas expands from a volume of 1m³ to a volume of 2m³ against an external pressure of 10⁵Nm^-2. The work done by the gas will be

• 10² kJ

• 10² J

• 10³ J

• 10⁵ kJ

Given thermochemical equation, 2H₂ (g) + O₂(g) → 2H₂O,ΔH = -571.6 kJ. Heat of decomposition of water is

• -571.6 kJ

• +571.6 kJ

• -1143.2 kJ

• + 285.8 kJ

The ratio of heats liberated at 298 K from the combustion of one kg of coke and by burning water gas obtained from kg of coke is (Assume coke to be 100% carbon). (Given : enthalpies of combustion of CO₂, CO and H₂ as 393.5 kJ, 285 kJ, 285 kJ respectively all at 298 K)

• 0.79 : 1

• 0.69 : 1

• 0.86 : 1

• 0.96 : 1

The process is spontaneous at the given temperature, if

• ΔH is +ve and ΔS is -ve

• ΔH is -ve and ΔS is +ve

• ΔH is +ve and ΔS is +ve

• ΔH is +ve and ΔS is equal to zero.

For an ideal binary liquid mixture.

• $∆{\mathrm{S}}_{\left(\mathrm{mix}\right)} = 0; ∆{\mathrm{G}}_{\left(\mathrm{mix}\right)} = 0$

• $∆{\mathrm{H}}_{\left(\mathrm{mix}\right)} = 0; ∆{\mathrm{S}}_{\left(\mathrm{mix}\right)} < 0$

• $∆{\mathrm{V}}_{\left(\mathrm{mix}\right)} = 0; ∆{\mathrm{G}}_{\left(\mathrm{mix}\right)} > 0$

• $∆{\mathrm{S}}_{\left(\mathrm{mix}\right)} > 0; ∆{\mathrm{G}}_{\left(\mathrm{mix}\right)} < 0$

The correct statement regarding entropy is

• at absolute zero temperature, entropy of a perfectly crystalline solid is zero

• at absolute zero temperature, the entropy of a perfectly crystalline substance is positive

• at absolute zero temperature, the entropy of all crystalline substances is zero

• at 0°C, the entropy of a perfect crystalline solid is zero