Year 12 Chemistry Tutorial 9.2.A Synthetic Polymers

Transcription

1 Year 12 Chemistry Tutorial 9.2.A Synthetic Polymers Module Topic 9.2 Production of Materials 9.2.A Synthetic Polymers Name Date Ethene 1. Match the statement on the left with the most appropriate answer on the right. Raw material from which ethene is produced. Process of using a catalyst to break down high molecular weight fractions from crude oil into lower molecular weight substances. non- polar ethene Inorganic catalysts used for cracking alkanes. Non- catalytic process using steam in which alkanes are decomposed into smaller alkenes. catalytic cracking alkenes Group of hydrocarbons containing a double bond. Physical property which enables hydrocarbons to be separated by fractional distillation. alkanes petroleum Type of intermolecular forces which exist between hydrocarbon molecules. Nature of hydrocarbons which means they are insoluble in water. Hydrocarbons which contain only single bonds. Most widely used starting substance for making polymers. zeolites boiling point dispersion forces thermal cracking 2. Write a balanced equation for the cracking of (a) hexadecane (C 16 ) into a C 9 alkane and a C 7 alkene.

2 (b) decane (C 10 ) into a C 8 alkane and a C 2 alkene. 3. Write balanced equations for the following reactions, draw structural formulae and name the products. (a) 1- pentene with Cl 2 (b) 3- hexene with bromine water (c) 2- butene with H 2 (d) ethene with HCl Page 2

3 4. Four bottles containing clear liquids were found on a laboratory shelf but the labels had fallen off. The missing labels were found on the floor and had the names: hexene, pentane, water and ethanol. A group of chemistry students were asked to devise a series of tests to identify the contents of each of the four bottles. The students labelled the bottles A, B, C and D and conducted their tests. Here are their results. BOTTLE SOLUBLE IN WATER BURNS DECOLOURISES BROMINE A Yes No No B No Yes Yes C No Yes No D Yes Yes No (a) Using the information from the table, identify which bottle contained which chemical and justify your choice. (b) Write balanced equations for the reactions that occurred. Page 3

4 Addition Polymers 5. Complete the following statements. a) A chemical reaction in which many small molecules, called, combine together to form one large molecule is called. The large molecule is called a. b) An polymer is formed by molecules adding together without the loss of any atoms. For this type of polymer to form, the basic unit must contain a bond. c) When ethene polymerises it forms the polymer which consists of anywhere between to monomer units. Another name for this polymer is polyethene. d) There are two processes used to form polyethylene. The older process uses high pressures, high and an initiator. The alkane chains produced in this process cannot pack closely together in an orderly way because of the amount of chain. This product is called polyethylene. e) The newer process uses lower temperatures and than the older process because it relies on to promote the reaction. This Zeiger- Natta process forms chains which are able to pack more closely together in an orderly fashion. This product is called polyethylene. 6. Explain why LDPE molecules have lower melting points than HDPE molecules. 7. The arrangement of long chain molecules in HDPE and LDPE is shown below. LDPE has many side chains which prevent the molecules from packing together while HDPE is more rigid and does not soften at temperatures below 1000C. a) Explain what causes the difference in density between the two types of polyethylene. Page 4

5 b) Which form would you expect to have the greatest mechanical strength? Justify your choice. c) Which type would be more suitable for a washing up bowl and a cordial bottle? Justify your answers. d) Explain why a shopping carrier bag made from polyethylene is a greater hazard to the environment than a paper one. 8. Complete the following table. Polymer Systematic Name of Monomer Structure of Monomer Common Uses Important Properties Relating to Use LDPE HDPE PVC Polystyrene Page 5

6 9. The following items are made from a synthetic polymer rather than the traditional material listed. Complete the table giving one advantage and one disadvantage of the new material over the old. ITEM OLD MATERIAL NEW MATERIAL ADVANTAGE DISADVANTAGE Drain pipe Metal PVC Does not corrode Not as strong Carrier bag Paper Carpet Electrical insulation wiring Soft drink bottles 10. Identify a thermoplastic and its use. Describe the properties of the plastic and relate those properties to its use. 11. Write chemical equations to show the polymerisation of: a) polyethylene b) polyvinylchloride c) polystyrene Page 6