Chemistry- Year 10, Unit 1

Getting Oil from Plants- many plants produce fruit, seeds and nuts that are rich in oilsm which can be extracted and changed into consumer products. Some common examples you might find in the food you eat are...

• sunflower oil
• olive oil
• oilseed ****
• palm kernel oil

Oil can be extracted from plant materials by pressing (crushing) them or by distillation. This removes the water and other impurities from the plant material.

Margarine is manufactured from unsaturated vegetable oils like sunflower oil. The oil is reacted with hydrogen, at a temperature of around 60'C in the presence of a nickel catalyst and some of the double bonds are hydrogenated. Removing more double bonds make the margarine harder.

Additives- Many processed foods have different substances added to them to improve their look, texture of flavour or to help preserve them, Some of these additives are natural, but the majority are produced by the chemical industry.

Additives have to be shown in the list of ingredients on the label. Some of the additives that are allowed to be added to foods are called E-numbers.

Chemical Analysis- Chemical analysis can be used to identify additives in food. Chromatography is a method used to identify artificial colours.

Chromatography identifies unknown substances, by comparing them to known substances. A sample of four known substances (A, B,C and D) and the unknown substance (X) are put on a 'start line' on a piece of paper, which is then dipped into a solvent. As the solvent is absorbed by the paper, it dissolves the samples and carried them up the paper by differing amounts due to different substances having different solubilities. Substance X can be identified by comparing the horizontal sports.