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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


B.

ΔH< 0 and ΔS > 0

According to the Gibbs-Helmholtz reaction for spontaneity as,

ΔG =ΔH-TΔS

For reaction to being spontaneous, ΔG must be negative.
For this ΔH should be negative ΔS should be positive.
therefore,

ΔHΔS >0.


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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


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 


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