In the upper atmosphere, ozone is produced from oxygen gas in the following reaction. 3O2(g) → 2O3(g)

Question

ΔH^o for this reaction= 285 kJ

ΔS^o for ozone formation= -141 kJ

ΔG^o for ozone formation= 326 kJ

Assume an atmosphere where p(O₂) = 0.150 atm, and where T = 298 K. Below what pressure of O₃ will ozone production be spontaneous? (Enter your answer in atm).

Answer 1

The units need to be checked and/or corrected:

ΔH^o for this reaction= 285 kJ/mol

ΔS^o for ozone formation= -141 kJ/mol*K

ΔG^o for ozone formation= 326 kJ/mol

Assuming the units match the above, the following equation would be useful:

ΔH_f^° = ΔG_f^° + TΔS_f^°

However, according to the Argonne National Lab website, the ΔH_f^° for ozone at 298K is 141.7 kJ/mol, and this seems to disagree with the calculated value from the equation above.