C1!

C1!

1. Fundamental ideas

   • Atoms
     • all substances are made from atoms
     • This is a periodic table. It is where all the elements are stored.
       • The top number is the mass number. It indicates the number of protons and neutrons
       • The bottom number indicates the number of protons in the neucleus
       • The letters in the centre are the symbol
     • There are 3 types of subatomic particle.
       • Electron- mass 1/2000. Charge -1. Number always equal to number of protons
       • Proton- mass 1, charge 1
       • Neutron- mass 1, charge 0.
     • Most of an atom is empty space
     • Electrons are arranged in 'shells' around the nucleus. Shell 1 holds 2, shell 2 holds 8, shell 3 holds 8 and shell 4 holds 8.
       • The number of electrons in the outer shell is indicated by the number above the group (column)
       • The shells fill in order
     • All atoms of one element are the same
     • Most of an atom is empty space
   • Equations
     • Must always be balanced
     • This is the balanced symbol equation for water
     • State symbols show the state of matter. (s)=solid (l)=liquid (g)=gas (aq)=aqueous
     • No atoms are lost or created
     • Equations represent the reactants and the products and can be word or symbol
     • Never use an equals! Always an arrow!
   • Chemical Reactions
     • Atoms with fewer than 8 electrons in their outer shell undergo reactions to be stable
     • When non-metals react they share their electrons
       • Covalent bond
     • When metals and non-metal or metals react they transfer elctrons
       • Ionic bond
         • If an atom loses electrons it becomes POSITIVELY charged
         • If an atom gains electrons it becomes NEGATIVELY charged
     • Shown through dot and cross diagrams and equations

2. Limestone

   • Limestone is mainly made from the compound calcium carbonate
   • Limestone is a type of sedimentary rock
   • Limestone is formed over millions of years from the bodies of dead plants and animals that lived in the sea
   • Lime kilns are often used to make lots of calcium oxide. Limestone goes in and is heated with hot air. Waste gases escape.
   • Chemical formula is CaCO3
   • Limestone is heated with clay to make cement
     • Cement is an important building material
       • You can add aggregate sand and water to cement to make concrete
         • Concrete is VERY strong. Reinforced concrete is where steel rods are surrounded by concrete. This makes it even stronger.
   • Limestone is dug out of the ground at quarries and can be used in building
   • When we heat limestone strongly it undergoes THERMAL DECOMPOSITION and breaks down into two products: calcium oxide and carbon dioxide, so it turns lime water cloudy
   • Calcium carbonate in limestone reacts with acids in the rain. With sulphuric acid it produces calcium sulphate, carbon dioxide and water.

3. Metals!

   • Ways to extracts copper
     • Electrolysis- where you make a solution of copper carbonate and sulphuric acid and place two carbon electrodes into it. The electrode attached to the negative will attract copper
     • Bioleaching- bacteria are left to feed on low grade copper ores. They then produce leachates which contain copper compounds.
     • Phytomining- some plants are absorb copper compounds through their roots. They can then be burned. The ash contains higher grade copper compounds
   • Blast furnace-Heamatite s heated strongly in a furnace with coke and limestone. They react and produce iron, carbon dioxide and carbon monoxide.
   • Aluminium is high in the reactivity series so is difficult and expensive to extract. The ore has to be purified and then electrolysis is used to get the metal. This requires lots of heat and energy.
     • During electrolysis aluminium oxide splits to form aluminium and oxygen.- 2AL203->4AL+302
     • In molten aluminium the ions are free to move. The aluminium ions are attracted to the nedative electrode. When they get there they gain electrons to form molten aluminium, which sinks to the bottom of the tank and is drained out.
   • To extract titanium from it's ore we use a more reactive metal like sodium. Titanium must be turned into a chloride and purified before it is displaced

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