Chemistry Revision Notes

Alcohols make good fuels because they burn easily and they release a lot of heat energy, which can be harnessed to power machines etc... The combustion of alcohol is an exothermic reaction and this me click here for full revision note

Fractional distillation is the process of heating up a mixture containing different substances with different boiling points, and drawing the different fractions off as they each boil and liquify at i click here for full revision note

The general formula for alkenes is as follows: CnH2n   (where "n" is a constant) Alkenes are unsaturated hydrocarbons because they contain a double bond between two of their carbon click here for full revision note

The general formula for alkanes is as follows: CnH2n+2   (where "n" is a constant) The first ten members of the homologous series of the alkanes are: CH4     (Metha click here for full revision note

Organic chemistry is the study of carbon compounds. The number of different organic compounds which are known is well over 1 million and these compounds vary in properties, economic importance and us click here for full revision note

The carbon cycle is simply the process by which Carbon Dioxide is put into and removed from the atmosphere. This process is very finely balanced to keep the percentage of CO2 in the atmosphere at 0.03 click here for full revision note

There are 3 main processes undertaken in the water purifying process: Filtration Bacterial Oxidation Chlorine Treatment The different stages are listed in more detail below: Water pumped f click here for full revision note

Temporary Hard Water This is caused by calcium or magnesium hydrogen-carbonate. It can be removed by boiling the water. Ca(HCO3)2 (aqueous)   ---->   CaCO3 (solid)   +   H2 click here for full revision note

Soap contains salts such as sodium stearate and sodium palmitate and when calcium ions in hard water mix with soap, a precipitate of calcium stearate / calcium palmitate is formed. In the following eq click here for full revision note

Hard water does not produce as much lather as soft water when it is used with soap and also an insoluble solid called scum is left on the sides of the wash basin. Calcium chloride, Magnesium nitrate, click here for full revision note