RI Y4 Chem 2022 FE Revision Acids Bases Salts Ionic Eqn ANS.pdf

1 Raffles Institution Raffles Programme Year Four Chemistry Name: ____________________________ ( ) Class: ______ Date: _______ 2022 FE Revision – Acids, Bases and Salts; Ionic Equations Answers nitric acid HNO3 calcium hydroxide Ca(OH)2 sulfuric acid H2SO4 ammonia NH3 ethanoic acid CH3COOH copper(II) oxide CuO Reactions of Acids 1 HCl + NaOH  NaCl + H2O 2 2HNO3 + CaCO3  Ca(NO3)2 + H2O + CO2 3 H2SO4 + Mg  MgSO4 + H2 Reactions of Bases 1 CaO + 2HCl  CaCl2 + H2O 2 NaOH + NH4Cl  NaCl + H2O + NH3 3 2NaOH + Fe(NO3)2  2NaNO3 + Fe(OH)2 green ppt 2NaOH + CuSO4  Na2SO4 + Cu(OH)2 blue ppt Strength of Acids and Bases 1 A strong acid is one that completely ionises/dissociates in water while a weak acid is one that partially ionises/dissociates in water 2(a) (i) strong acid (ii) strong base (iii) + H+(aq) weak acid (iv) + OH−(aq) weak base 2(b) CH3COOH + KOH  CH3COOK + H2O 2CH3COOH + Na2CO3  2NaCH3COO + H2O + CO2 2CH3COOH + Mg  (CH3COO)2Mg + H2 ⇌ 2H+ + 3 A 10 mol dm–3 solution of hydrochloric acid is a concentrated solution of a strong acid while a 0.1 mol dm–3 solution of hydrochloric acid is a dilute solution of a strong acid. 4 (strong) acid, concentration [H+] / mol dm−3 pH sulfuric acid, H2SO4, 0.0100 mol dm−3 H2SO4 is dibasic: 1 mol H2SO4 dissociates to produce 2 mol H+ 0.0200 −lg (0.0200) = 1.70 Solubility rules and Precipitation reactions sulfate most, except… BaSO4, calcium sulfate and PbSO4 chloride most, except… silver chloride and PbCl2 iodide most, except… AgI and Lead(II) iodide O C CH2 C O O O-- Acid-Base titrations Titration pH of equivalence point circle your choice strong alkali - strong acid <7 / =7 / >7 strong alkali - weak acid <7 / =7 / >7 * weak alkali - strong acid <7 / =7 / >7 * Types of Oxides Na2O + 2HCl → 2NaCl + H2O CuO + H2SO4 → CuSO4 + H2O ZnO CO2 + 2NaOH → Na2CO3 + H2O SiO2 + CaO → CaSiO3

2 aqueous silver nitrate and aqueous sodium iodide / potassium iodide silver iodide aqueous zinc nitrate and aqueous sodium carbonate zinc carbonate aqueous iron(III) nitrate and aqueous sodium hydroxide iron(III) hydroxide aqueous lead(II) nitrate and aqueous sodium chloride lead(II) chloride 1 Na2CO3 (aq) + CaCl2 (aq)  2NaCl (aq) + CaCO3 (s) 2 2NaOH (aq) + CuSO4 (aq)  Cu(OH)2 (s) + Na2SO4 (aq) Writing Ionic Equations Cl2 (g) + 2I– (aq)  2Cl– (aq) + I2 (s) Cu2+ (aq) + Zn (s)  Zn2+ (aq) + Cu (s) (a) 3OH− (aq) + Fe3+ (aq)  Fe(OH)3 (s) red-brown precipitate: iron(III) hydroxide (b) Ag+ (aq) + Cl− (aq)  AgCl (s) white precipitate: silver chloride Practice Questions 1 D 2 D 3 A 4 D 5 C 6 method