At a certain temperature, the ph of a neutral solution is 7.64. what is the value of kw at that temperature? express your answer numerically using two significant figures.

It is very important to know that neutral pH changes with temperature. The key part to this problem is that the solution is neutral! In a neutral solution the pH and pOH are equal and therefor so are their concentrations. Kw = [H]*[OH] where [H] and [OH] represent the concentrations of those ions. pH=-log[H] antilog (-pH) = [H] Antilog is fancy way of saying 10^x. In our case x=-7.64 [H]=2.95 x 10^-8 M (Molarity) Since pH and pOH are equal in our neutral solution so are their concentrations. [OH]=2.95 x 10^-8 M Now we go back to Kw = [H]*[OH] and plug in the concentrations. Kw = (2.95 x 10^-8) * (2.95 x 10^-8) = 8.71 x 10^-16