crude oil

crude oil

Synthetic and natural materials
1. The materials we use are chemicals or mixtures of chemicals. For example, sugar is a chemical, but chocolate is a mixture of chemicals , one sugar
2. Materials can be obtained or made from living things. Examples include cotton, paper, silk and wool. These are sometimes called natural materials.
3. Materials can also be made from chemicals.Examples of these are plastics such as polythene used in shopping bags. These are called syntheetic material
Refining crude oil
1. rude oil is a raw material obtained from the Earth’s crust. It is a mixture of many different chemicals, most of which are hydrocarbons.
2. Crude oil is not very useful until it has been processed at an oil refinery.
  1. The process of refining involves separating the hydrocarbons into fractions or batches using a technique called fractional distillation
    1. Each fraction separates as they have different boiling points. The crude oil is heated in a furnace to around 400°C.
      1. his allows all of the hydrocarbons in the crude oil to move into the bottom of the fractionating tower. The tower is hottest at the bottom and coolest
3. Size and properties of molecules
  1. The size of a molecule has an effect on the properties that molecule shows. For example, the boiling point of hydrocarbons increases as the number of
    1. carbon atoms in the molecule increases
    2. This is because forces between molecules increase as the size of the molecule increases.
      1. Hydrocarbons with up to four carbon atoms are gases, five to 16 carbon atoms are liquids and hydrocarbons with more than 16 carbon atoms are solids.
Polymerisation
1. Some small molecules (monomers) can join together to make very long molecules called polymers. This process is called polymerisation.
2. Many polymers are made from chemicals that are obtained from crude oil. For example, molecules of ethene join together to make poly(ethene),
3. By polymerising other small molecules, a wide variety of different polymers can be made. These synthetic materials have many uses.
Rearrangement of atoms
1. in a chemical reaction, the substances that react together are called the reactants, while the substances that are formed are called the products.
2. As a chemical reaction takes place, atoms in the reactants are rearranged to make the products.
  1. The number of atoms of each element in the reactants is the same in the products
    1. No atoms are added or taken away. This is called the conservation of atoms.
New synthetic materials
1. New synthetic materials are often used to make items that at one time were made from natural materials. The new material often has better properties,
2. Window frames used to be made from wood. This has to be painted regularly, and in time may rot. new window frames are made from uPVC, a syntheticpolym
  1. The ‘u’ means it is unplasticised so is different from regular PVC. This can be made in a variety of colours, never needs to be painted, does not rot

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	Criado por jakeogilvie mais de 11 anos atrás