Consider the three hypothetical reactions shown below. In all cases, the value o
ID: 556252 • Letter: C
Question
Consider the three hypothetical reactions shown below. In all cases, the value of G° = 5.00 kJ mol-1 for each reaction. The concentration for each species in each reaction is given next to the reaction. You may assume that T = 25.0 °C. What is the value of G (not G°) for each of these reactions under these conditions?
Reaction 1: A B + C
[A] = 50.0 mM
[B] = 500. mM
[C] = 10.0 mM
G = kJ mol-1
Reaction 2: D + E F
[D] = 100. mM
[E] = 5.00 mM
[F] = 10.0 mM
G = kJ mol-1
Reaction 3: G H
[G] = 50.0 mM
[H] = 100. mM
G = kJ mol-1
Explanation / Answer
reaction 1 )
A ------------------> B + C
Q = [B][C]/[A]
Q = 50 x 500 x 10^-3 / 10
Q = 2.5
G = G° + R T ln Q
= 5.00 + 8.314 x 10^-3 x 298 x ln (2.5)
= 7.27 kJ / mol
G = 7.27 kJ / mol
b)
reaction : D + E -----------------> F
Q = 10 / 100 x 5 x 10^-3
Q = 20
G = 12.4 kJ / mol
similarly
reaction 3)
G = 6.72 kJ / mol