Scientific research: We know that oil comes out of the ground is called crude oil. Crude oil was formed from the remains of tiny sea animals and plants, which died millions of years ago. It is a mixture of substances called hydrocarbons. These are compounds of hydrogen and carbon. “At an oil refinery, the different substances in crude oil are separated in a fractionating tower. The oil is boiled so that most rises up the tower as vapour (gas). As it rises, it cools different substances condense (turn to liquid) at different temperatures, and are collected at different levels.
The different parts of mixture are called fractions. Separating fractions by boiling is called fractional distillation. Heavier Fractions have longer molecules than lighter fractions. Using a chemical process called cracking, long molecules can be broken up to make shorter ores. So, if there is too much diesel oil, It can be changed into petrol by cracking. Short molecules can also be joined together to make longer ones. This process is called polymerisation. ” (Source 1) Cracking Hydrocarbons with large molecules have higher boiling points than those with smaller molecules.
They also burn less easily. To get more useful fuel, a large hydrocarbon molecule can be cracked by heating with steam or a catalyst. Two smaller molecules are formed. One is still an alkane – a hydrocarbon with only single bonds. The other is an alkene – a hydrocarbon with at least one double bond in its chain. This is said to be unsaturated because extra atoms can add when the double bonds break down to a single bond again. By contrast, alkanes are saturated. Below molecules are shown using structural formulae. Diagram page 112 (Source 1)
Addition Polymerisation “The short unsaturated molecules (monomers) can join up with each other when their double bonds break open. This is called addition polymerisation. The very long chain molecule formed is a polymer (commonly known as plastic). Diagram page 112 (Source 1) The diagram above shows how the simplest alkane, ethane, is changed into polythene. The process can be represented by an equation, in which n is a variable number of ethene molecules (up to 4000) NCH2C = CH2NH4N. ” (Source 1) Condensation Polymerisation
“Some polymers are found when two different monomers link together by eliminating molecules of water. This is condensation polymerisation, and it must happen at both ends of each monomer to produce a giant polymer molecule, as shown below. Diagram of Condensation Polymerisation The polymer nylon bb can be made from 1,6 diaminohexane and hexanedix acid. Polyester is another condensation polymer. ” (Source 1) Prediction: It think that the thickest oil is going to move down the glass slide the slowest, because it is made up of the most hydrocarbon atoms.
This makes the oil heavier and thicker. I also think that as the oil gets thinner the oils move down quicker because they are made up of less hydrocarbon atoms. I can now say that the oils that are heated up to 50 degrees Celsius are going to move down the slide quicker than the oils that are not heated. I say this because when oil is heated up it becomes thinner and the thinner the oil the quicker it runs down the slope. Apparatus: 5x pipette, 1 slide, 5x test-tube containing 5 different types of oil, tripod, rubber bung, Bunsen burner, pencil, felt-tip, paper.