BEHS Chemistry The Math of PH   PH is defined as the NEGATIVE log of the hydrogen ion concentration   PH = -log [H +]   Because H + is always in equilibrium with water and INVERSLY proportional to OH - concentration (as one increases the other decreases).     HOH <---> H + + OH -   We can also have the "POWER of the hydroxide ion" value, or pOH:   POH = -log [ OH -]   Also remember the ion product constant for water:   [H +] x [ OH -] = 1x10 -14 moles/liter 2   With some mathematical manipulation this also means that:   PH + pOH = 14   With all this information, you can solve problems involving pH: PROBLEMS 1. What is the pH of a solution with a [H +] of 1 x 10 -8?   2. What is the [H +] of a solution with a pH of 3?   3. What is the pOH of a solution with a pH of 5?   4. What is the [ OH -] of a solution with a pH of 4?   5. If you wanted to change the pH of a solution from 3 to 5, how many times would you dilute it?
Contact: Tom Davidson, Box Elder High School 380 So. 600 w. (435-734-4840) Email: tom.davidson@besd.net