Question

For the elementary gas-phase reaction O3 + NO  NO2 + O2, one finds that Ea = 2.5 kcal/mole and A = 6 X 108 dm3mol-1s-1 for the temperature range 220 – 320 K. Calculate ΔG0c‡, ΔHoc‡, and ΔSoc‡ for the midpoint of this temperature range.

Answer 1

Ea = 2.5 KCal / mol

Ea = 2.5 x 4.184 kJ/mol

Ea = 10.46 kJ/mol

we know that

according to arhenius equaiton

k = Ae^-(Ea/RT)

so

using given values

k = 6 x 10^8 x e^(-10.46 x 1000 / 8.314 x 270)

k = 5.68 x 10^6

now

we know that

dGo = -RT ln k

so

dGo = -8.314 x 270 x ln 5.68 x 10^6

dGo = -34912 J/mol

dGo = -34.912 kJ /mol

now

Ea = dHo + RT

so

10.46 x 1000 = dHo + ( 8.314 x 270)

dHo = 8215.22

so

dHo = 8.215 kJ/mole

now

dGo = dHo - TdSo

so

-34912 = 8215.22 - ( 270 x dSo)

dSo = 159.7

so

dSo = 159.7 J/mol