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Topic 11. Metals. Aim of lesson:. Discuss the reaction of metals with: Oxygen Dilute Acid Water Carry out a reaction to test the reactivity of metals with dilute acid. Reaction of Metals. When a metal reacts is loses electrons to form positive ions.
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Topic 11 Metals
Aim of lesson: • Discuss the reaction of metals with: • Oxygen • Dilute Acid • Water • Carry out a reaction to test the reactivity of metals with dilute acid.
Reaction of Metals • When a metal reacts is loses electrons to form positive ions. e.g. Mg Mg2+ + 2e- • The metals atoms are oxidised. These reactions allow metals to be placed in a certain order REACTIVITY SERIES Metals HIGH in the reactivity series are MORE reactive and so more readily form ions and compounds.
Reactivity Series • Some metals are more reactive than others. • The reactivity series places the most reactive metals at the top and the least reactive metals at the bottom. • We can place metals in order of reactivity by comparing how well they react with other substances e.g. • Oxygen • Dilute acid • Water
most reactive least reactive Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Hydrogen Copper Mercury Silver Gold Platinum K Na Li Ca Mg Al Zn Fe Sn Pb H Cu Hg Ag Au Pt
Reacting Metals with Oxygen • When metals are heated with air they may react with the oxygen present. • Metal + Oxygen Metal oxide • Some metals react vigorously with oxygen and burn fiercely, some react more slowly and others do not react at all!
Mineral wool Potassium permangante Pyrex test tube Magnesium or Copper Heat Heat Experiment Aim: To investigate the reactions of magnesium and copper when burned in a plentiful supply of oxygen. Method:
Results: Conclusion: Magnesium is more reactive than copper.
Magnesium + oxygen magnesium oxide Mg + O2 2 2 MgO Sodium + oxygen sodium oxide Na2O 2 Na + O2 4 Potassium + oxygen Potassium oxide 4 2 K + O2 K2O Formulae Equations
Reacting metals with dilute acid • Some metals react with dilute acids to produce salts and hydrogen. Metal + Acid Salt + Hydrogen
Experiment Aim: To investigate the reaction of different metals with acid. Method:
Results: Magnesium reacts vigorously with acid. Copper does not react with acid. Metals above hydrogen in the ECS react with acids to produced hydrogen gas, but metals below hydrogen do not react with acids. Metal + Acids Salt + Hydrogen
or Al + HCl AlCl3 + H2 Metals Reacting with Acid Magnesium + HCl Magnesium chloride + H2 2 Mg + HCl MgCl2 + H2 Potassium + HCl Potassium chloride + H2 2 K + HCl 2 2 KCl + H2 Aluminium + HCl Aluminium chloride + H2 Al + HCl 3 AlCl3 + H2 1.5 6 3
Reacting Metals with Water • Some metals react with water and displace hydrogen to give an alkaline solution. • Metal + Water Metal hydroxide + hydrogen • Again, some metals react more vigorously than others.
Potassium, sodium and lithium react so violently with water that they must be stored in oil, to prevent them reacting with moisture in the air!
Conclusion: • When metals react with water an alkali is produced. Hydrogen gas is also formed. Metal + Water Metal Hydroxide + Hydrogen
Metals Reacting with water Lithium + H2O Lithium hydroxide + Hydrogen 2 2 2 Li + H2O LiOH + H2 Sodium + H2O Sodium hydroxide + Hydrogen 2 Na + H2O 2 2 NaOH + H2 Magnesium + H2O Magnesium hydroxide + Hydrogen Mg + H2O 2 Mg(OH)2 + H2
Metal + Oxygen Metal oxide Metal + Acid Salt + Hydrogen Metal + Water Metal hydroxide + hydrogen Remember!
Quick Quiz • Where can the most reactive metals be found in the reactivity series? • What is produced when metals react with oxygen? • What is produced when metals react with acid? Most reactive metals at top, least reactive metals at the bottom. Metal oxide Salt and hydrogen