6. Zuren en basen

6. Zuren en basen 6. Zuren en basen

10.09.2013 Views

pH van oplossingen van zwakke basen • NH 3 + H 2O NH 4 + + OH - K B = [OH - ] e.[NH 4 + ]e /[NH 3] e = 1,78.10 -5 [NH 3] e = [NH 3] 0 en [NH 4 + ]e = [OH - ] e ⇒ [OH - ] = √ K B.[NH 3] 0 [NH 3] = 0,1 mol/l ⇒ pOH = 2,88 ⇒ pH = 11,12 [NH 3] = 0,01 mol/l ⇒ pOH = 3,38 ⇒ pH = 10,62 • 1 t.e.m. 3 Oefeningen p. 133

pH van oplossingen van zouten • MX M + + X - • Soms: M + = Brønstedzuur X - = Brønstedbase Zout (0,1 mol/l) Zuur K z Base K b pH NaCl Na(H 2O) 6 + 2.10 -15 Cl - 1.10 -21 7,0 Al(NO 3) 3 Al(H 2O) 6 3+ 1.10 -5 NO 3 - 1.10 -16 3,0 Na 2CO 3 Na(H 2O) 6 + 2.10 -15 CO 3 2- 1,78.10 -4 11,6 NH 4Ac NH 4 + 5,62.10 -10 Ac - 5,62.10 -10 7,0 NaHCO 3 HCO 3 - 5,62.10 -10 HCO 3 - 2,34.10 -8 8,3 • Als K

pH van oplossing<strong>en</strong> van zwakke bas<strong>en</strong><br />

• NH 3 + H 2O NH 4 + + OH -<br />

K B = [OH - ] e.[NH 4 + ]e /[NH 3] e = 1,78.10 -5<br />

[NH 3] e = [NH 3] 0 <strong>en</strong> [NH 4 + ]e = [OH - ] e<br />

⇒ [OH - ] = √ K B.[NH 3] 0<br />

[NH 3] = 0,1 mol/l ⇒ pOH = 2,88 ⇒ pH = 11,12<br />

[NH 3] = 0,01 mol/l ⇒ pOH = 3,38 ⇒ pH = 10,62<br />

• 1 t.e.m. 3<br />

Oef<strong>en</strong>ing<strong>en</strong> p. 133

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