Question

CH6Q17

The value of ΔG°'ΔG°′ for the conversion of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate (GAP) is +7.53 kJ/mol+7.53 kJ/mol. If the concentration of dihydroxyacetone phosphate at equilibrium is 2.25 mM2.25 mM, what is the concentration of glyceraldehyde-3-phosphate? Assume a temperature of 25.0°C25.0°C.

[GAP]= _________ mM

Answer 1

Answer :

Reaction is

Dihydroxyacetone phosphate ----> glyceraldehyde-3-phosphate

Equilibrium constant (K) = [Product] / [Reactant]

[Reactant] = [dihydroxyacetone phosphate] = 2.25 mM

∆G° for this reaction = 7.53 KJ/ mol = 7530 J /mol

T (Temperature) = 25°C = 298 K

R(gas constant) = 8.314 J /K mol

∆G° = -RT* lnK

lnK = - ∆G° / RT = - 7530 / ( 8.314 * 298) = -3.04

So,

lnK = -3.04

Taking exponential both sides

K = exp (-3.04) = 0.0478

Since , K =[ Product] / [Reactant] = 0.0478

[Product] = 0.0478 * [Reactant] = 0.0478 * 2.25 mM = 0.107mM

So, [Product] = [glyceraldehyde-3-phosphate] = 0.107 mM