[malsumis145]

The description of the problem is in the attachment. I have solved the problem but my results differ greatly from the results given to solve the next problem. Can you tell me where my mistake is?

[mjc123]

First, your final calculation is wrong - why do you use 364.77 instead of 36.477? and you have ignored a factor of 1000. The answer, with your numbers, should be 35 M, which is obviously wrong.
The real problem is with your partition coefficient of 43*10^-8. Where did you get this from? I find values (at 25°C) of around 1.2 [c(g)/c(aq)] or 0.83 [c(aq)/c(g)], which corresponds to a K_H of 2980 Pa m³/mol, and a CO₂ concentration of 12.2 μM. That looks more like it.