Analytical Chemistry
posted by Sam on .
Carbon dioxide dissolves in water to form carbonic acid, which is primarily dissolved CO2. Dissolved CO2 satisfies the equilibrium equation.
CO2(g) <> CO2(aq)
The acid dissociation constants listed in most standard reference texts for carbonic acid actually apply to dissolved CO2. K=0.032 M/atm
For a CO2 partial pressure of 4.4×104 atm in the atmosphere, what is the pH of water in equilibrium with the atmosphere?
Note: Since carbonic acid is primarily dissolved CO2, the concentration of H2CO3 can be taken as equal to that of dissolved CO2.
My online homework is due tonight and I am hopelessly lost on how to solve this problem. :(

Try this.
C = pK
C = 4.4E4*0.032 = about 1.41E5
H2CO3 ==> H^+ + HCO3^
k1 = (H^+)(HCO3^)/(H2CO3)
(H^+)= (HCO3^) = x
(H2CO3) = 1.41E5
Solve for x = (H^+) and convert to pH.
Are you plugging this into a data base? If so let me know how it turns out? And show your work when you do. 
Yes I have online homework which I use to submit my homework on. I calculated H2CO3 and got the same value as yours. then I solved for x and got 2.3 x 10^6 M. Finally i plugged it into the ph formula to get a ph of 5.64. Thank you so much! It was correct!

for once Dr Bob is right lol. he is usually wrong

Dr Bob is almost always right, don't be so salty ashley