Consider the reaction X Y at 300 K. If H^ and K are 28.40 kJ mol^ -1 and 1.8 10^ -7 at the same temperature, then the magnitude of S^ for the reaction in J K^ -1 mol^ -1 is _______. (Nearest integer) (Given: R = 8.3 J K^ -1 mol^ -1 , 10 = 2.3, 3 = 0.48, 2 = 0.30)
A. A
The standard Gibbs free energy change is given by: G^ = -RT K = -2.3 RT K First, calculate K: K = (1.8 10^ -7 ) = (18 10^ -8 ) K = 18 - 8 = (2 3^2) - 8 K = 2 + 2 3 - 8 Substituting the given values: K = 0.30 + 2(0.48) - 8 = 0.30 + 0.96 - 8 = 1.26 - 8 = -6.74 Now, calculate G^ : G^ = -2.3 8.3 300 (-6.74) = 38599.98 J mol ^ -1 Using the relation G^ = H^ - T S^ : 38599.98 = 28400 - 300 S^ 300 S^ = 28400 - 38599.98 = -10199.98 S^ = - 10199.98 300 -34 J K ^ -1 mol ^ -1 The magnitude of S^ is 34. Answer: 34
Related: Chemistry — Thermodynamics (C) · All PYQ Banks