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Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC Kw 1.0 x 10-14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC Kw 1.0 x 10-14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw 1.0 x 10-14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] 1.0 x 10-7 M
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH 7
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH < 7
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH < 7
[OH-] 1.0 x 10-7 M
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH < 7
[OH-] > 1.0 x 10-7 M
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH < 7
[OH-] > 1.0 x 10-7 M pOH 7
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH < 7
[OH-] > 1.0 x 10-7 M pOH < 7
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH < 7
[OH-] > 1.0 x 10-7 M pOH < 7
@ this temperature pH + pOH
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH < 7
[OH-] > 1.0 x 10-7 M pOH < 7
@ this temperature pH + pOH ≠ 14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Higher Temperatures
@ 50 oC shifts right Kw > 1.0 x 10-14
[H+] > 1.0 x 10-7 M pH < 7
[OH-] > 1.0 x 10-7 M pOH < 7
@ this temperature pH + pOH ≠ 14 = pKw
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC Kw 1.0 x 10-14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw 1.0 x 10-14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] 1.0 x 10-7 M
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH 7
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH > 7
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH > 7
[OH-] 1.0 x 10-7 M
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH > 7
[OH-] < 1.0 x 10-7 M
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH > 7
[OH-] < 1.0 x 10-7 M pOH 7
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH > 7
[OH-] < 1.0 x 10-7 M pOH > 7
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH > 7
[OH-] < 1.0 x 10-7 M pOH > 7
@ this temperature pH + pOH
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH > 7
[OH-] < 1.0 x 10-7 M pOH > 7
@ this temperature pH + pOH ≠ 14
Kw and Temperature
Energy+ H2O ⇋ H+ + OH-
@ 25 oC Kw = 1.0 x 10-14
Lower Temperatures
@ 0 oC shifts left Kw < 1.0 x 10-14
[H+] < 1.0 x 10-7 M pH > 7
[OH-] < 1.0 x 10-7 M pOH > 7
@ this temperature pH + pOH ≠ 14 = pKw
Important Points
If you're not @ 25oC
[H+][OH-] ≠ 1.0 x 10-14
pH + POH ≠ 14
All other equations are valid and…….
Pure water is always neutral, but pH ≠ 7 and…….
[H+] = [OH-] and ……
pH = pOH
1. The pH of pure water is 6.50 Is the temperature higher or lower than 25 oC? Calculate the Kw.
[H+] = 10-6.50 = 3.1623 x 10-7 M
Energy+ H2O ⇋ H+ + OH-
Higher
[OH-] = 3.1623 x 10-7 M
Kw = [H+][OH-] =(3.1623 x 10-7)2
Kw = 1.0 x 10-13