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Observation     What you see during an experiment. You should look carefully at the substances before they react, while they are reacting and after they have reacted. Observations should include a colour and a physical state. A good onservation could be something like "a pale brown liquid was formed near the positive electrode". That is far better than, "it went brown".

Some people make the mistake of saying something like, "hydrogen was produced" instead of , "a colourless gas was produced which, when tested later, burned with a squeeky pop".

Oil     Crude oil is the decayed remains of plants and animals that lived in the sea. The oil has been formed over a few million years. Crude oil is the major source of alkanes.

Ore     A substance that can be used as a source of a metal. Haematite is an ore of iron. To be useful, an ore has to have a high enough percentage of the metal in it to be economically viable to extract.

Oxidation     A reaction in which oxygen is added to a substance. For every oxidation, there is always a reduction (something losing oxygen) of some kind.

Oxide     The new substance that is formed when a substance has reacted with oxygen.

Metal oxides are bases...they neutralise acid

Non-metal oxides are usually acids. A few oxides are neutral.

Oxide layer     Some metals (like iron) have oxides tha crumble away to expose new metal. Some metals (aluminium and titanium are two good examples) forms oxide layers that are tough and protect the metal from further attack. Think about the position of aluminium in the reactivity series (very high) but yet it is used to make window frames that have to resist corrosion for many years. If you want to see the true reactivity of aluminium ask your teacher to show you aluminium in water once it has had its oxide layer removed by rection with mercury.

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