The difference between ΔH and ΔU ( ΔH- ΔU), when the combustion of one mole heptane(I) is carried out a temperature T, is equal to:

• -3RT

• -4RT

• 3RT

• 4R

562.

The correct thermodynamic conditions for  the spontaneous reaction at all temperatures is

• ΔH> 0 and Δ S< 0
• ΔH< 0 and ΔS > 0
• ΔH ΔS >0
• ΔH ΔS >0

Which of the following statements is correct for a reversible process in a state of equilibrium?

• ΔG = -2.303RT log K

• ΔG = 2.303RT log K

• ΔG⁰ = -2.303RT log K

• ΔG⁰ = -2.303RT log K

Which of the following statement is correct for the spontaneous absorption of a gas?

• ΔS is negative and therefore, ΔH should be highly positive
  
• ΔS is negative and therefore, ΔH should be highly negative
• ΔS is positive and therefore, ΔH should be negative
• ΔS is positive and therefore, ΔH should be negative

For the reaction X₂O₄ (l) -->  2XO₂ (g) ΔU = 2.1 kcal, ΔS = 20 cal K^-1 at 300 K hence ΔG is

• 2.7 kcal

• -2.7kcal

• 9.3 kcal 

• 9.3 kcal 

A reaction having equal energies of activation for forward and reverse reactions has

• ΔS =0
• ΔG =0
• ΔH = 0
• ΔH = 0

In which of the following reactions, standard reaction entropy changes (ΔS^o) is positive and standard Gibb's energy change (ΔG^o) decreases sharply with increasing temperature?

• C (graphite) +1/2 O₂ (g) → CO (g)

• CO (g) +1/2 (g) → CO₂ (g)

• Mg(s)  +1/2O₂ (g) → MgO (s)

• Mg(s)  +1/2O₂ (g) → MgO (s)

The enthalpy of fusion of water is 1.435 Kcal/mol. The molar entropy change for the melting of ice of at 0^o C is

• 10.52 cal/(mol K)

• 21.04 cal/(mol K)

• 5.260 cal/ (mol K)

• 5.260 cal/ (mol K)

Standard enthalpy of vaporisation Δ_vapH^θ for water for water at 100^oC is 40.66 kJ mol^-1. The internal energy of vaporisation of water at 100^o C (in KJ mol^-1) is

(Assume water vapour to behave like an ideal gas.)

• +37.56

• -43.76

• +43.76

• +43.76

If the enthalpy change for the transition of liquid water to steam is 30kJ mol^-1 at 27^oC, the entropy change for the process would be. 

• 1.0 J mol^- K^-1

• 0.1 J mol^-1 K^-1

• 100 J  mol^-1 K^-1

• 10 J mol^-1 K^-1