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Review of Acids. HCl Strong Acid HCl H + + Cl - 0.10 M 0.10 M pH = -Log[H + ] = 1.0 No ICE HF Weak Acid HF ⇌ H + + F - I 0.10 M 0 0 C x x x E 0.10 - x x x small Ka x 2 = 3.5 x 10 -4 x = 0.005916 M 0.10
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Review of Acids
HClStrong AcidHCl H+ + Cl- 0.10 M 0.10 M pH = -Log[H+] = 1.0 No ICE HFWeak AcidHF ⇌ H+ + F- I0.10 M 0 0 C x x x E 0.10 - x x x small Ka x2 = 3.5 x 10-4 x = 0.005916 M 0.10 pH = -Log[0.005916] = 2.23
NaOHStrong BaseNaOH Na+ + OH- 0.20 M 0.20 M pOH = -Log[OH-] = 0.70 No ICE NH3Weak BaseNH3 + H2O ⇌NH4+ + OH- I0.20 M 0 0 C x x x E 0.20 - x x x small Kb x2 = Kb = Kw = 1.0 x 10-14 = 1.786 x 10-5 0.20 Ka 5.6 x 10-10 x = 0.001890 M pOH = -Log[0.001890] = 2.73 pH = 11.27
CaO Basic AnhydrideCaO + H2O Ca(OH)2 SO2Acid AnhydrideSO2 + H2O H2SO3 Salts NaClneutral salt NaCl Na+ + Cl- KCNbasic salt CN- + H2O ⇌ HCN + OH- hydrolysis NH4Clacidic salt NH4+ + H2O ⇌ H3O+ + NH3 hydrolysis
FeCl3acidic salt Fe(H2O)63+⇌ H+ + Fe(H2O)5(OH)2+ hydrolysis- copy off chart! Know the pH scale 0 7 14 HCl HF NaCl NH3 NaOH Assuming 1M
BuffersMaintain the pH Weak Acid + Salt ( conjugate) HF KF HF ⇌ H+ + F- High Low High IndicatorChange colour with pH HInd ⇌ H+ + Ind- Acid Low Basic
IndicatorsChange colour with pH methyl red HInd ⇌ H+ + Ind- redyellow page 7 @ trans pt [HInd] = [Ind-] colour is orange and Ka = [H+] pH = 4.8 + 6.0 = 5.4 2 Ka = [H+] = 10-5.4= 4 x 10-6
Acid RainSO2 NO2 pH 5 Normal RainCO2pH = 6 AmphriproticH2C2O4 acid HC2O4- ampriprotic C2O42-base Is HC2O4- an acid or base? Ka (HC2O4-) = 6.4 x 10-5 Kb (HC2O4-) = 1.0 x 10-14 = 1.7 x 10-13 5.9 x 10-2acid
Is NH4CH3COO an acid or base? Ka (NH4+) = 5.6 x 10-10 Kb (CH3COO-) = 1.0 x 10-14 = 5.6 x 10-10 1.8 x 10-5neutral
100.0 mL 0.100 M H2SO4 is mixed with 220.0 mL of 0.100 M NaOH. What is the pH of the resulting solution? H2SO4 + 2NaOH 0.1000 L x 0.100 mole 0.2200 L x 0.100 mole 1 L 1 L I 0.0100 mole 0.0220 mole C 0.0100 mole 0.0200 mole E 0 mole 0.0020 mole [NaOH] = 0.0020 mole = 0.00625 M 0.320 L pOH = 2.20 pH = 11.80
Complete the reaction and state if the reactants or products are favoured. HCO3- + HSO3- Base Acid HCO3- + HSO3- ⇌H2CO3 + SO32- weaker weaker stronger strongerbase acid acid base Reactants are favoured
Know the Equations E + H2O ⇌ H+ + OH- Kw = [H+][OH-] = 1.0 x 10-14 pH = -Log[H+] pOH = -Log[OH-] [H+] = 10-pH [OH-] = 10-pOH pH + pOH = pKw = 14 @ 25 oC @ other temperatures pure water is always neutral & [H+] = [OH-] & pH = pOH 7