ENTROPY-GIBBS.doc - File Entropy Gibbs(pp 147,148 284,286 287 Page 147 1 For a certain reaction,H = 22 kcal andG = 12 kcal at 25oC(a CalculateS(b For

# ENTROPY-GIBBS.doc - File Entropy Gibbs(pp 147,148 284,286...

• Notes
• 5

This preview shows page 1 - 2 out of 5 pages.

File: Entropy - Gibbs (pp. 147,148, 284,286, 287) Page 147 1. For a certain reaction,H = _22 kcal andG = _12 kcal at 25oC. (a) CalculateS. (b) For the same reaction, calculateG when the temperature is 500K. 2.TheH for a certain reaction is _30 kcal and theS, _0.08 kcal per degree K. CalculateG at 25oC. Will this reaction occur spontaneously at 500K? 3.Explain by calculatingG, why KCl crystals will dissolve in water at 25oC, although theH is positive.H = + 2.0 kcal;S = + 23 cal/ K (0.023 kcal/ K) 4. For a given reaction,H = 20.0 kcal andG = 16 kcal at 25oC. Calculate the value of (a)S (b)G at 800 KAns. (a) 0.013 kcal/ K 5. For the phase change, H2O(s) H2O(l), the value ofH is 1440 cal/mole. TheS value is 5.26 cal/mole-degree.CalculateG and state whenever the change is spontaneous at (a) + 10.0oC and (b) _ 10.0 o C Ans. (a) _ 0.0490 kcal/mole (b) + 0.05662 kcal/mole --------------------------------------------------------------------------------------------------------- ------------- 6. Determine whether the following reaction is spontaneous: C (s)( graphite) + O 2(g) CO 2(g) H = _ 393.5 kJ/mol S = + 0.003 kJ/K,mol G =
• • • 