Reactivity Series of Metals Reactions of Metals Effect of Heat on Metal Carbonates

Reactivity Series of Metals Chemical Properties of Metals Metal reaction with cold water & steam Metal reaction with hydrochloric acid Reaction of Metals: Displacement Reactions With aqueous ions of another metal With the oxide of another metal Reaction of Metal Oxides With carbon With hydrogen Effect of Heat on Metal Carbonates Thermal stability & reactivity Reactivity Series of Metals

Recap: Chemical Properties of Metals Reaction with Water (Cold Water) Metal + Cold Water  Metal Hydroxide + Hydrogen Gas Eg. 2Na(s) + 2H2O(l)  2NaOH(aq) + H2(g) Which are some metals that react with cold water?

Recap: Chemical Properties of Metals Reaction with Water (Steam) Metal + Steam  Metal Oxide + Hydrogen Gas Eg. Mg(s) + H2O(g)  MgO(s) + H2(g) Which metals only react with steam?

Recap: Chemical Properties of Metals Reaction with Hydrochloric Acid Metal + Hydrochloric Acid  Salt + Hydrogen Gas Eg. 2K(s) + 2HCl(l)  2KCl(aq) + H2(g) The more vigorous the reaction The higher it is in the reactivity series The more reactive is the metal

Reaction of Metals With the Aqueous Ions of Another Metal Displacement of metals from solution More reactive metals can displace less reactive metals from their salt solutions. This can be used to find the position of metals in the reactivity series.

Iron Nail in Copper(II) Sulphate Solution Observations: Reddish-brown solid forms on the surface of the iron nail Blue solution becomes pale green Fe (s) + CuSO4 (aq)  FeSO4 (aq) + Cu (s) Iron Copper(II) Sulphate Solution Iron(II) Sulphate Solution Copper

Iron Nail in Copper(II) Sulphate Solution Brown solid: Copper metal Solution turns pale green Copper has been removed from the solution. Iron(II) sulphate solution is pale green in colour. We say that… Iron has displaced copper from the copper(II) sulphate solution.

What will happen when a piece of magnesium strip is immersed in a solution of copper(II) sulphate? Think!

Some Possible Observations Deposit of the more reactive metal (from its aqueous solution) Colour of the solution may change Heat may be given off Grey: zinc, iron, lead Reddish-brown: copper

Displacement Reactions are Redox Reactions The more reactive metal is oxidized The less reactive metal is reduced For example, Chemical Equation: Fe (s) + CuSO4 (aq)  FeSO4 (aq) + Cu (s) Ionic Equation: Fe (s) + Cu2+ (aq)  Fe2+ (aq) + Cu (s) REDOX reaction! Copper(II) ions are reduced to become copper atoms Iron atoms are oxidized to become iron(II) ions

Displacement Reactions are Redox Reactions A more reactive metal: readily gives up electrons in reactions has greater tendency to form positive ions As a result… A more reactive metal can displace a less reactive metal, from its solution or metallic oxide.

Reaction of Metals With the Oxide of Another Metal Displacement of metals from metallic oxides A more reactive metal can reduce the oxide of a less reactive metal. For example: Thermit reaction 2Al (s) + Fe2O3 (s)  Al2O3 (s) + 2Fe (l) Magnesium acts as a fuse. It provides enough energy to start the reaction.

Reaction of Metals With the Oxide of Another Metal Thermit Reaction 2Al (s) + Fe2O3 (s)  Al2O3 (s) + 2Fe (l) The more reactive the metal is, the more readily it forms compounds. Unreactive metals tend to stay umcombined. Iron(III) ions are reduced to become iron atoms Aluminium atoms are oxidized to become aluminium(III) ions

Reaction of Metal Oxides With Carbon Carbon can remove oxygen from the oxides of metals that are not too high up in the Reactivity Series. The lower the position of a metal in the Reactivity Series, the easier it is for carbon to remove oxygen from the metal oxide.

Reaction of Metal Oxides With Carbon potassium oxide sodium oxide calcium oxide magnesium oxide oxides are not reduced by carbon zinc oxide iron(II) oxide lead(II) oxide copper(II) oxide oxides are reduced by carbon silver oxide oxide is reduced by heating silver oxide decomposed to give silver and oxygen

Reaction of Metal Oxides With Carbon The Importance! Reaction of Metal Oxides With Carbon metals need to be extracted from their ores before we can use them metals below magnesium are often extracted from their ores by reduction with carbon (WHY?) metals above zinc cannot be extracted by reduction with carbon bc they are stable (THEN WHAT?)

metal oxide + hydrogen  metal + steam Reaction of Metal Oxides With Hydrogen Hydrogen can remove oxygen from metallic oxides, producing the metal and water(steam). metal oxide + hydrogen  metal + steam The lower the position of a metal in the Reactivity Series, the easier it is for hydrogen to remove oxygen from the metal oxide.

reaction with hydrogen Reaction of Metal Oxides With Hydrogen metal oxide reaction with hydrogen potassium oxide sodium oxide calcium oxide magnesium oxide zinc oxide heated metal oxides are not reduced by hydrogen iron(II) oxide lead(II) oxide copper(II) oxide silver oxide heated metal oxides are reduced by hydrogen

Effect of Heat on Metal Carbonates: Thermal Stability & Reactivity Most carbonates decompose when heated strongly to produce a metal oxide and carbon dioxide gas. The ease of decomposition depends on the position of the metal in the reactivity series. Recall the reactivity series.

Thermal Stability of Metal Carbonates Effect of Heat Potassium Carbonate Stable to heat No visible reaction Sodium Carbonate Calcium Carbonate Decomposes into metal oxide and carbon dioxide Magnesium Carbonate Zinc Carbonate Iron (III) Carbonate Lead Carbonate Copper(II) Carbonate Silver Carbonate Decomposes into silver and carbon dioxide  Metal Metal Oxide + Carbon Dioxide Silver carbonate decomposes to form silver oxide, which further decomposes to silver bc it is thermally unstable.

Reactions with water & dilute acids: More vigorous reaction  Higher in the reactivity series  The metal is more reactive Reaction with metal carbonates: The more stable the metal carbonate is to heat, the higher it is in the reactivity series.

Class Activity & Discussion Check this out! http://www.chem.iastate.edu/group/Greenbowe/se ctions/projectfolder/flashfiles/redox/home.html Class Activity & Discussion

So, what have you learnt today? Displacement Reaction They are redox reactions. A more reactive metal can displace a less reactive metal, from its solution or metallic oxide. Carbonates: Thermal stability & reactivity The more stable the metal carbonate is to heat, the higher it is in the reactivity series.