In the upper atmosphere, ozone is produced from oxygen gas in the following reac
ID: 990781 • Letter: I
Question
In the upper atmosphere, ozone is produced from oxygen gas in the following reaction. 3O2(g) 2O3(g) Calculate Go for this reaction. Enter your answer in kJ and give 3 significant figures.
Calculate Ho for ozone formation. (Enter your answer in kJ and give 3 significant figures).
Calculate So for ozone formation. (Enter your answer in J/K and give 3 significant figures).
Assume an atmosphere where p(O2) = 0.025 atm, and where T = 298 K. Below what pressure of O3 will ozone production be spontaneous? (Enter your answer in atm).
Explanation / Answer
3 O2 ------> 2 O3
From thermodynamic tables,
delta G = 2 x 163.2 - 3 x 0 == 326 kJ
delta H = 2 x 143 - 3 x 0 == 286 kJ
delta S = 2 x 238 - 3 x 205.03 == - 139 J/K
0 = RT ln (( P O3 )^2 / (P O2 )^3 )
P (O3)^2 = P (O2)^3
P O3 = 0.0253/2 == 0.004 atm