Moderators: Chem_Mod, Chem_Admin

Erin Jannusch
Posts: 14
Joined: Fri Sep 29, 2017 7:07 am


Postby Erin Jannusch » Fri Dec 08, 2017 12:45 pm

What is pKw used to calculate? I know that it can be found by multiplying the concentrations of hydronium and hydroxide ions, but I am wondering what this calculation in used for and what it really tells us about a solution.

Ryan Sydney Beyer 2B
Posts: 82
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

Re: pKw

Postby Ryan Sydney Beyer 2B » Fri Dec 08, 2017 1:16 pm

In a soln. of water, the hydroxide conc multiplied by the hydronium conc is going to equal 1 X 10^-14. If you take the negative log of both sides of this eqn it shows you that the pH added to the pOH is going to equal 14.

[H+] [OH-] = Kw = 1 X 10-14
Take the -log of both sides of the equation
- log [H+] +(- log [OH- ]) = - log [1 X 10-14 ]
pH + pOH = 14

Return to “Calculating pH or pOH for Strong & Weak Acids & Bases”

Who is online

Users browsing this forum: No registered users and 3 guests