2. Metals and their Properties TOPIC 11

3. Metals and their Properties Metals have distinctive properties such as: 4. Malleability. 3. Strength 2. Good Thermal Conductivity 1. Electrical Conductivity

4. Reactions of Metals General Equation With Oxygen All metals react with Oxygen. The more reactive the metal the quicker the reaction. In the lab the oxygen is produced by heating potassium permanganate. The brighter the glow the more the reactive the metal. Less reactive metals produce a duller glow Metal Oxide Metal + Oxygen

5. Metals + Oxygen (continued) Potassium permanganate acts as a source of oxygen when Heated Mg metal is placed between two pieces of ceramic wool The more active the metal the brighter the glow

6. Reactions of Metals Metal + H 2 O With Water Only metals above hydrogen in the Activity Series react with water. In fact only the first three react with cold water. The remaining metals above hydrogen must be treated with steam before a reaction will take place. General Equation Metal Hydroxide + H 2

7. Reactions of Metals Metal + Acid With Acids Only Metals above Hydrogen in the Activity Series react with Acids. General Equation Salt + Hydrogen

8. Pop Pop When a metal is reacted with an acid it produces H2 H2 gas which burns with a POP! Metals and Acid (continued)

9. Alloys An Alloy is a mixture of metals or metals and other elements. Alloys are made to change the properties of the metal e.g.to make them harder, more pleasing on the eye or to make them more resistant to corrosion. Examples are: brass ( Cu + Zn ), gold ( Au + Cu ) ( the greater the proportion of Cu the lower the no.of carats), stainless steel ( Fe, Ni and Cr )

10. Metal Ores Most metals are found combined with other elements such as, oxygen and sulphur in the earths crust. These are called Metal Ores. Only gold, silver and platinum are found uncombined. As a result metals must be mined and then separated from their ores by metal extraction

11. Extraction of Metals from their Ores Ores of metals high up in the electrochemical series contain stronger bonds and therefore require more sophisticated and expensive methods of extraction Metals low down in the Electrochemical Series form weak bonds with other elements. As a result ores of these metals can broken up easily to obtain the metal.

12. Electrochemical Series Can be broken by heat alone Must be electrolysed to release metal from ore Platinum Gold SilverMercury PotassiumSodium Calcium Magnesium Aluminium HYDROGEN CopperZincLead Tin Iron Separated from ore by heating with CHARCOAL, thus releasing CARBON DIOXIDE.