C1- Metals and Non-metals

C1- Metals and Non-metals

1. Metals, Ores and Reactivity

   • An ore is a substance found in the Earth's crust containing metal atoms combined with other elements. E.g- Hematite, magnetite, bauxite
   • Metals can be extracted from their ores by chemical reactions or electrolysis
   • Some very unreactive metals, like gold, silver and platinum can be found uncombined with other elements
   • The difficulty of extracting metals from their ores (amount of energy needed) increases as their reactivity increases
   • Metals can be arranged in order of their reactivity in a reactivity series
   • Any metal can displace a metal lower than it in the reactivity series from a solution of one of its salts. E.g- magnesium + copper sulfate = copper + magnesium sulfate

2. Extracting Metals from their Ores

   • Many chemical reactions used to extract metals from their ores involve the processes of reduction and oxidation
   • REDUCTION- Removal of oxygen atoms from a chemical
   • OXIDATION- Addition of oxygen atoms to a chemical
   • Extraction of iron from iron ore
     • Reduction/ Oxidation Reaction
     • Iron ore is reduced to iron at high temperatures (in a blast furnace) by the oxidation of carbon (from coke) while carbon (and carbon monoxide) are oxidised to carbon dioxide
   • Extraction of Aluminium
     • Aluminium is higher than iron and carbon in the reactivity series, so we need much more energy to extract it from its ore and reduction/ oxidation reactions involving carbon cannot be used
     • Aluminium (and higher metals in the reactivity series) are extracted using electrolysis
     • Aluminium oxide is heated to high temperatures making it melt. This allows positively charged aluminium ions to move towards the negatively charged cathode, forming aluminium atoms that can be extracted as bulk aluminium metal

3. Sustainability Issues with the Extraction of Metals from their Ores

   • Siting of the plant (large land use, contamination of land, environmental impact, effect on local population
   • Fuel and energy costs
   • Greenhouse gas emissions
   • Impact of recycling
   • Effects of the extraction of the ores on the environment and the local population

4. Properties and Uses of Some Common Metals

   • Aluminium
     • PROPERTIES- Strong, Low density, Good conductor of heat and electricity, Resistant to corrosion
     • USES- High-voltage power line, Saucepans, Window and greenhouse frames, Drinks cans, Aeroplane and car parts
   • Copper
     • PROPERTIES- Very good conductor of heat and electricity, Malleable, Ductile, Lustrous, Attractive colour
     • USES- In alloys like brass and bronze, Water pipes, Electrical wires, Jewellery and ornaments, saucepan bottoms
   • Titanium
     • PROPERTIES- Hard, Strong, Low density, High melting point, Resistant to corrosion
     • USES- Jet engine and spacecraft parts, Industrial machine parts, Car parts, Medical implants, Strengthening steel, Jewellery, Sports equipment

5. Alloys

   • Mixtures of two or more different metals (or carbon) made by combining the molten metals
   • The properties of the allow can be modified by varying the types and amounts of the metals in the mixture
   • EXAMPLES- Brass, Bronze and Stainless steel

6. Nano-Particles

   • Tiny Particles
   • 1-100 nanometres- 1nm= 1 x 10 to the power of -9 m
   • Added in very small quantities to products to give the product a special property
   • Silver
     • One of the most commonly used nano-particles
     • Added to products to make them antibacterial
     • PRODUCTS THAT BENEFIT FROM THIS- Fridges and Other household appliances, Soaps, Clothes and Medical dressings- products that commonly come into contact with human skin
   • Gold nano-particles are used to manufacture high-efficiency solar panels and small but high capacity and voltage batteries
   • Potential health and environmental question associated with the use of nano-particles. E.g- In high quantities, metals like silver can be toxic, more research is needed to investigate these claims

7. Hydrogen and Oxygen

   • Production of Non-metals
     • Many non-metals are found in the air, including nitrogen (78%), oxygen (21%) and argon (less than 1%)
     • These gases can be extracted commercially by fractional distillation of liquid air
     • Hydrogen and Oxygen can be produced from water by electrolysis and twice as much hydrogen as oxygen is produced
   • Testing for Hydrogen and Oxyegn
     • HYDROGEN GAS- Collect the gas and ignite it with a lighted splint- hydrogen gas explodes with a 'pop'
     • OXYGEN GAS- Collect the gas and insert a glowing splint into the test-tube- oxygen will re-light the glowing spling
     • Hydrogen and oxygen are two of the most important gases that we use
   • Uses of Ozygen
     • In Medicine as an aid to breathing
     • For producing high temperatures (as in oxyacetylene welding)
     • In liquid form to burn with rocket fuel
   • Uses of Hydrogen
     • Petrochemicals industry for making certain types of hydrocarbon
     • Food industry for making margarine
     • Fuel in hydrogen fuel cells
     • ADVANTAGES- High energy yield, Non-polluting
     • DISADVANTAGES- Highly flammable (explosive), Needs to be stored in a pressurised tank, Few 'filling stations' at present, Electricity is used to manufactore hydrogen from water by electrolysis

8. The Halogens and the Noble Gases

   • HALOGENS- Elements in Group 7 (fluorine, chlorine, bromine, iodine and astatine)
   • Halogens react with metals to produce haildes
   • Reactivity of the halogens increases going up the group
   • Chlorine and iodine can be obtained from the compounds produced by the evaporation of sea water
   • NOBLE GASES- Very unreactive elements in Group 0