15saltspp.ppt
- 1. ACIDS, BASES AND SALTS A guide for A level students 2015 SPECIFICATIONS KNOCKHARDY PUBLISHING
- 2. INTRODUCTION This Powerpoint show is one of several produced to help students understand selected topics at AS and A2 level Chemistry. It is based on the requirements of the AQA and OCR specifications but is suitable for other examination boards. Individual students may use the material at home for revision purposes or it may be used for classroom teaching if an interactive white board is available. Accompanying notes on this, and the full range of AS and A2 topics, are available from the KNOCKHARDY SCIENCE WEBSITE at... www.knockhardy.org.uk/sci.htm Navigation is achieved by... either clicking on the grey arrows at the foot of each page or using the left and right arrow keys on the keyboard KNOCKHARDY PUBLISHING ACIDS, BASES AND SALTS
- 3. BRØNSTED-LOWRY THEORY ACID proton donor HCl ——> H+(aq) + Cl¯(aq) BASE proton acceptor NH3(aq) + H+(aq) ——> NH4 +(aq) ACIDS AND BASES
- 4. ACIDS proton donors release H+ ions (protons) in aqueous solution STRONG ACIDS Hydrochloric HCl —> H+(aq) + Cl¯(aq) 1 replaceable H MONOPROTIC Nitric HNO3 —> H+(aq) + NO3¯(aq) 1 replaceable H MONOPROTIC Sulphuric H2SO4 —> 2H+(aq) + SO4 2-(aq) 2 replaceable H’s DIPROTIC ACIDS
- 5. ACIDS proton donors release H+ ions (protons) in aqueous solution STRONG ACIDS Hydrochloric HCl —> H+(aq) + Cl¯(aq) 1 replaceable H MONOPROTIC Nitric HNO3 —> H+(aq) + NO3¯(aq) 1 replaceable H MONOPROTIC Sulphuric H2SO4 —> 2H+(aq) + SO4 2-(aq) 2 replaceable H’s DIPROTIC WEAK ACIDS Ethanoic CH3COOH(aq) CH3COO¯(aq) + H+(aq) MONOPROTIC ACIDS
- 6. BASES proton acceptors react with acids by accepting H+ ions to form salts e.g. carbonates K2CO3 MgCO3 CuCO3 hydrogencarbonates NaHCO3 metal oxides MgO ZnO CuO metal hydroxides NaOH KOH Ca(OH)2 ammonia NH3 BASES AND ALKALIS
- 7. BASES proton acceptors react with acids by accepting H+ ions to form salts e.g. carbonates K2CO3 MgCO3 CuCO3 hydrogencarbonates NaHCO3 metal oxides MgO ZnO CuO metal hydroxides NaOH KOH Ca(OH)2 ammonia NH3 ALKALIS SOLUBLE BASES which release OH¯ (hydroxide ions) in aqueous solution e..g. Soluble metal oxides sodium oxide Na2O + H2O(l) ——> 2Na+(aq) + 2OH¯(aq) Soluble metal hydroxides sodium hydroxide NaOH ——> Na+(aq) + OH¯(aq) potassium hydroxide KOH ——> K+(aq) + OH¯(aq) Aqueous ammonia NH3(aq) + H2O(l) NH4 + (aq) + OH¯(aq) or NH3(aq) + H+(aq) NH4 +(aq) BASES AND ALKALIS
- 8. SALTS Formed from the reaction between acids and bases hydrochloric acid makes CHLORIDES nitric acid makes NITRATES sulphuric acid makes SULPHATES / HYDROGENSULPHATES SALT FORMATION A salt is produced when the H+ ion of an acid is replaced by... a metal ion or the ammonium ion NH4 + SALTS
- 9. SALTS Formed from the reaction between acids and bases hydrochloric acid makes CHLORIDES nitric acid makes NITRATES sulphuric acid makes SULPHATES / HYDROGENSULPHATES SALT FORMATION A salt is produced when the H+ ion of an acid is replaced by... a metal ion or the ammonium ion NH4 + SUMMARY Acids react with... metals to give a salt + hydrogen oxides of metals a salt + water hydroxides of metals a salt + water carbonates a salt + water + carbon dioxide hydrogencarbonates a salt + water + carbon dioxide ammonia an ammonium salt SALTS
- 10. Water of crystallisation • loosely bonded water molecules attached to salts CuSO4.5H2O FeSO4.7H2O Na2CO3.10H2O • the water can be driven off by heating e.g. CuSO4.5H2O(s) ———> CuSO4(s) + 5H2O(l) WATER OF CRYSTALLISATION
- 11. Water of crystallisation • loosely bonded water molecules attached to salts CuSO4.5H2O FeSO4.7H2O Na2CO3.10H2O • the water can be driven off by heating e.g. CuSO4.5H2O(s) ———> CuSO4(s) + 5H2O(l) HYDRATED copper(II) sulphate ANHYDROUS copper(II) sulphate BLUE CRYSTALS WHITE POWDER WATER OF CRYSTALLISATION
- 12. Is a typical acid in dilute aqueous solution HCl ——> H+ (aq) + Cl¯(aq) REACTIONS OF HYDROCHLORIC ACID Hydrogen chloride is a colourless covalent gas; it is a poor conductor of electricity because there are no free electrons or ions present. It has no action on dry litmus paper because there are no aqueous hydrogen ions present.
- 13. Is a typical acid in dilute aqueous solution HCl ——> H+ (aq) + Cl¯(aq) REACTIONS OF HYDROCHLORIC ACID Hydrogen chloride is a colourless covalent gas; it is a poor conductor of electricity because there are no free electrons or ions present. It has no action on dry litmus paper because there are no aqueous hydrogen ions present. If the gas is passed into water, the hydrogen chloride molecules dissociate into ions. The solution now conducts electricity showing ions are present. For each hydrogen chloride molecule that dissociates one hydrogen ion and one chloride ion are produced. The solution turns litmus paper red because of the H+(aq) ions.
- 14. Is a typical acid in dilute aqueous solution HCl ——> H+ (aq) + Cl¯(aq) REACTIONS OF HYDROCHLORIC ACID Hydrogen chloride is a colourless covalent gas; it is a poor conductor of electricity because there are no free electrons or ions present. It has no action on dry litmus paper because there are no aqueous hydrogen ions present. If the gas is passed into water, the hydrogen chloride molecules dissociate into ions. The solution now conducts electricity showing ions are present. For each hydrogen chloride molecule that dissociates one hydrogen ion and one chloride ion are produced. The solution turns litmus paper red because of the H+(aq) ions.
- 15. Is a typical acid in dilute aqueous solution HCl ——> H+ (aq) + Cl¯(aq) REACTIONS OF HYDROCHLORIC ACID HYDROGEN CHLORIDE HYDROCHLORIC ACID colourless gas Appearance colourless soln. covalent molecule Bonding aqueous ions HCl(g) Formula HCl(aq) poor Conductivity good no reaction Dry blue litmus goes red
- 16. Is a typical acid in dilute aqueous solution HCl ——> H+ (aq) + Cl¯(aq) REACTIONS OF HYDROCHLORIC ACID Appearance Bonding and formula Conductivity Dry litmus hydrogen chloride colourless gas covalent molecule HCl(g) poor no reaction hydrochloric acid colourless soln. aqueous ions HCl(aq) good goes red Hydrogen chloride is a colourless covalent gas; it is a poor conductor of electricity because there are no free electrons or ions present. It has no action on dry litmus paper because there are no aqueous hydrogen ions present. If the gas is passed into water, the hydrogen chloride molecules dissociate into ions. The solution now conducts electricity showing ions are present. For each hydrogen chloride molecule that dissociates one hydrogen ion and one chloride ion are produced. The solution turns litmus paper red because of the H+(aq) ions. SUMMARY
- 17. Metals magnesium + dil. hydrochloric acid ——> magnesium chloride + hydrogen Mg(s) + 2HCl(aq) ——> MgCl2(aq) + H2(g) REACTIONS OF HYDROCHLORIC ACID 1. WRITE OUT THE BALANCED EQUATION FOR THE REACTION
- 18. Metals magnesium + dil. hydrochloric acid ——> magnesium chloride + hydrogen Mg(s) + 2HCl(aq) ——> MgCl2(aq) + H2(g) Mg(s) + 2H+(aq) + 2Cl¯(aq) ——> Mg2+(aq) + 2Cl¯(aq) + H2(g) REACTIONS OF HYDROCHLORIC ACID 1. WRITE OUT THE BALANCED EQUATION FOR THE REACTION 2. DILUTE ACIDS AND SALTS CONTAIN IONS; WATER, HYDROGEN & CARBON DIOXIDE DON’T
- 19. Metals magnesium + dil. hydrochloric acid ——> magnesium chloride + hydrogen Mg(s) + 2HCl(aq) ——> MgCl2(aq) + H2(g) Mg(s) + 2H+(aq) + 2Cl¯(aq) ——> Mg2+(aq) + 2Cl¯(aq) + H2(g) cancel ions Mg(s) + 2H+(aq) ——> Mg2+(aq) + H2(g) REACTIONS OF HYDROCHLORIC ACID 1. WRITE OUT THE BALANCED EQUATION FOR THE REACTION 2. DILUTE ACIDS AND SALTS CONTAIN IONS; WATER, HYDROGEN & CARBON DIOXIDE DON’T 3. CANCEL OUT THE IONS WHICH APPEAR ON BOTH SIDES OF THE EQUATION
- 20. Metals magnesium + dil. hydrochloric acid ——> magnesium chloride + hydrogen Mg(s) + 2HCl(aq) ——> MgCl2(aq) + H2(g) Mg(s) + 2H+(aq) + 2Cl¯(aq) ——> Mg2+(aq) + 2Cl¯(aq) + H2(g) cancel ions Mg(s) + 2H+(aq) ——> Mg2+(aq) + H2(g) Basic Oxides copper(II) oxide + dil. hydrochloric acid ——> copper(II) chloride + water CuO(s) + 2HCl(aq) ——> CuCl2(aq) + H2O(l) Cu2+O2-(s) + 2H+(aq) + 2Cl¯(aq) ——> Cu 2+ (aq) + 2Cl¯(aq) + H2O(l) cancel ions O2- + 2H+(aq) ——> H2O(l) REACTIONS OF HYDROCHLORIC ACID
- 21. Alkalis sodium hydroxide + dil. hydrochloric acid ——> sodium chloride + water NaOH(aq) + HCl(aq) ——> NaCl(aq) + H2O(l) Na+(aq) + OH¯(aq) + H+(aq) + Cl¯(aq) ——> Na+ (aq) + Cl¯(aq) + H2O(l) cancel ions H+(aq) + OH¯(aq) ——> H2O(l) REACTIONS OF HYDROCHLORIC ACID
- 22. Alkalis sodium hydroxide + dil. hydrochloric acid ——> sodium chloride + water NaOH(aq) + HCl(aq) ——> NaCl(aq) + H2O(l) Na+(aq) + OH¯(aq) + H+(aq) + Cl¯(aq) ——> Na+ (aq) + Cl¯(aq) + H2O(l) cancel ions H+(aq) + OH¯(aq) ——> H2O(l) Carbonates calcium carbonate + hydrochloric acid ——> calcium chloride + carbon dioxide + water CaCO3(s) + 2HCl(aq) ——> CaCl2(aq) + CO2(g) + H2O(l) Ca2+CO3 2-(s) + 2H+(aq) + 2Cl¯(aq) ——> Ca2+(aq) + 2Cl¯(aq) + CO2(g) + H2O(l) cancel ions CO3 2- + 2H+(aq) ——> CO2(g) + H2O(l) REACTIONS OF HYDROCHLORIC ACID
- 23. Alkalis sodium hydroxide + dil. hydrochloric acid ——> sodium chloride + water NaOH(aq) + HCl(aq) ——> NaCl(aq) + H2O(l) Na+(aq) + OH¯(aq) + H+(aq) + Cl¯(aq) ——> Na+ (aq) + Cl¯(aq) + H2O(l) cancel ions H+(aq) + OH¯(aq) ——> H2O(l) Carbonates calcium carbonate + hydrochloric acid ——> calcium chloride + carbon dioxide + water CaCO3(s) + 2HCl(aq) ——> CaCl2(aq) + CO2(g) + H2O(l) Ca2+CO3 2-(s) + 2H+(aq) + 2Cl¯(aq) ——> Ca2+(aq) + 2Cl¯(aq) + CO2(g) + H2O(l) cancel ions CO3 2- + 2H+(aq) ——> CO2(g) + H2O(l) Hydrogen carbonates H+(aq) + HCO3¯ ——> CO2(g) + H2O(l) REACTIONS OF HYDROCHLORIC ACID
- 24. SUMMARY METALS react to give a salt + hydrogen METAL OXIDES react to give a salt + water METAL HYDROXIDES react to give a salt + water CARBONATES react to give a salt + water + carbon dioxide HYDROGENCARBONATES react to give a salt + water + carbon dioxide AMMONIA reacts to give an ammonium salt REACTIONS OF HYDROCHLORIC ACID
- 25. © 2015 JONATHAN HOPTON & KNOCKHARDY PUBLISHING THE END ACIDS, BASES AND SALTS