How does the K_{d} of pure water change with temperature?

Question

anonymous · Answer

i am assuming you mean the K for H2O <--> H+ + OH^-

i would look up the section in the book that discusses the temperature dependence of the equilibrium constant, especially the role that the enthalpy of reaction plays in determining whether it's a positive or negative change.

anonymous · Answer

the enthalpy of reaction of 
H+ + OH- => H20  is -57 kJ mol^-1, so I know that as temperature increases the dissociation of water into H+ and OH- will increase, I'm just wondering how much

it's not for a class, i'm just curious.

anonymous · Answer

you are right, sorry, when you asked "how does it change with temperature" i assumed you wanted to know the trend. gen-chem books usually don't tabulate Kw versus Temp, although they refer to them here and there in scattered places. i would look these up on the web.

i used your delta H to estimate the K2/K1 ratio for a temp increase of 5 degree Kelvin, and it's like 1.5 times higher. it sounds right but i would look these up.

anonymous · Answer

Searching for Kw vs. temperature for water gave me this: http://www.chemguide.co.uk/physical/acidbaseeqia/kw.html where they show a table with the changing pH of water at different temperatures. thank you for your help, this was very interesting.