# PH Scale. Ion product constant for water K w H 2 O  H + + OH - K w = [H + ] [OH - ] = 1.0 X 10 -14 mol/L Since [H + ] = [OH - ] for water Then each equals.

## Presentation on theme: "PH Scale. Ion product constant for water K w H 2 O  H + + OH - K w = [H + ] [OH - ] = 1.0 X 10 -14 mol/L Since [H + ] = [OH - ] for water Then each equals."— Presentation transcript:

pH Scale

Ion product constant for water K w H 2 O  H + + OH - K w = [H + ] [OH - ] = 1.0 X 10 -14 mol/L Since [H + ] = [OH - ] for water Then each equals 1.0 X 10 -7 M Water is neutral (neither acid or base)

The [H + ] or [OH - ] can be calculated if one is known…. Example: if [H + ] = 1.0 X 10 -5 Then, [OH - ] = 1.0 X 10 -9 because [H + ] [OH - ] must = 1.0 X 10 -14

If the [H + ] is larger than the [OH - ] then the solution is acid If the [OH - ] is larger than the [H + ], then the solution is basic

pH Concept that describes how acidic or how basic a solution is… pH = -log [H + ] Defined in terms of H + pH 7 base

pH scale 0 147 [H + ] = [OH - ] 10 -7 = 10 -7 [H + ] > 1.0 X 10 -7 [OH - ] > 1.0 X 10 -7 acidicbasic

http://www.quia.com/rd/1975.html

pOH pOH = -log [OH - ] pH + pOH = 14 14 – pOH = pH

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