Question 9 a) (4 points) For the reaction 2 A(aB(a)C (aq), the concentrations at
ID: 304598 • Letter: Q
Question
Question 9 a) (4 points) For the reaction 2 A(aB(a)C (aq), the concentrations at equilibrium of A (aq), B(aq) and C(aq) are respectively 0.277 M, 0.322 M and 0.411 M. What is the value of AG° for this reaction? When the system is in equilibrium, we add A(aq) until its concentration becomes 0.611 M. What is the value of ?G at that instant. The temperature remains 25.0°C (4 points) In the reaction 3 A(g) equilibrium. At equilibrium, the total pressure is 8.00 atm, and the partial pressure of B(g) is 1.50 atm. what is the value of ?G° for this reaction? The temperature remains 25.0°C. b) 2B(g) + 4C (g), we start with only pure A(g). We reachExplanation / Answer
1) For the reaction:
2A = B + C
we have a K = [B] * [C] / [A] ^ 2 we substitute the values ??and we have:
K = (0.322) * (0.411) / (0.277) ^ 2 = 1.725
The ?G = -RT * Ln (K) is then calculated
?G = - 8.314 * 298 * Ln (1.725) = - 1350.84 J / mol
2) For the reaction:
3A = 2B + 4C
we have:
Pa = x - 3y
Pb = 2y = 1.5 atm
Pc = 4y
clearing and of Pb we have:
y = 1.5 atm / 2 = 0.75 atm and we substitute Y in the partial pressures:
Pb = 1.5 atm
Pc = 3 atm
Pa = 8 - 1.5 - 3 = 3.5 atm
we calculate K = Pb ^ 2 * Pc ^ 4 / Pa ^ 3
K = (1.5) ^ 2 * (3) ^ 4 / (3.5) ^ 3 = 4.251
and finally we find out:
?G = - 8.314 * 298 * Ln (4.251) = -3585.43 J / mol.