Question

Consider a biochemical reaction under standard conditions.

A) the change in enthalpy is -7 kj/mol and the change in entropy is -25JK-1mol-1. With out doing any calculations can you determine if reaction is spontaneous?

B) calculate ΔG​ for the reaction at 5C

C) is the reaction spontaneous or not? Why or why not?

D)If not does raising the temperature make the reaction more likely to be spontaneous, or less likely to be spontaneous?

Answer 1

given that H = -7 kj/mol

entropy change S= -25J/K. mol = 0.025 kj/mol.K

and temperature T= 273+5= 278K

G= H - TS

= -7-278(-0.025)= -7+6.95= -0.05kj= -50 joules

yes this reaction spontaneous, because at low temperatures ,if free energy chage is negitive then entropy change will also be negitive( like above), hence the reaction is said to be spontaneous.

if does not raise temperature the reaction is more likely to be spontaneous.

at high temperatures, delta G is positive then the reaction is non spontaneous.