Question 1: Define addition polymerisation in your own words.

Answer: Addition polymerisation is a chemical process where small molecules called monomers join together to form a large polymer chain without the loss of any molecules.

Question 2: What are the typical conditions required for addition polymerisation to occur?

Answer: Addition polymerisation usually requires a catalyst or heat, and an initiator such as a free radical to start the reaction.

Question 3: Explain why no small molecules are lost during addition polymerisation.

Answer: Because the monomers simply add together at their double bonds, forming a long chain without releasing any molecules.

Question 4: Describe the role of free radicals in addition polymerisation.

Answer: Free radicals act as reactive species that initiate the breaking of double bonds in monomers, allowing them to link together and form polymers.

Question 1: If 1 mole of ethene (C₂H₄) produces 10,000 g of polyethylene (PE), what is the molecular weight of polyethylene?

Answer: Molecular weight of PE = (Mass of PE) / (Number of moles of ethene) = 10,000 g / 1 mol = 10,000 g/mol

Question 2: Calculate the number of monomer units in a polyethylene chain with a molecular weight of 200,000 g/mol. (Molecular weight of ethene = 28 g/mol)

Answer: Number of monomer units = (Molecular weight of polymer) / (Molecular weight of monomer) = 200,000 g/mol / 28 g/mol ≈ 7143 units

Question 1: Describe a basic experimental setup to demonstrate addition polymerisation of ethene in a classroom setting.

Answer: A simple setup involves passing ethene gas through a heated catalyst or using a UV light to initiate polymerisation in a controlled environment, observing the formation of a plastic-like substance.

Question 2: Identify at least two variables that could affect the rate of addition polymerisation in an experiment.

Answer: Temperature and concentration of initiator or catalyst.

Question 3: Name one safety precaution that should be taken during experiments involving addition polymerisation.

Answer: Ensure proper ventilation and wear safety goggles to protect against any reactive gases or heat.

Question 1: A scientist observes that increasing temperature speeds up the rate of addition polymerisation. Explain why this happens.

Answer: Higher temperatures increase the energy of molecules, making it easier for free radicals to form and react, thus speeding up the polymerisation process.

Question 2: In an industrial setting, why is controlling the temperature important during addition polymerisation?

Answer: To ensure the reaction proceeds at a controlled rate and to prevent overheating, which could cause unwanted side reactions or degradation of the polymer.

Question 1: Explain how addition polymerisation is used in the production of polyethylene bags. Include the basic process, conditions required, and safety considerations.

Answer: Polyethylene bags are produced by the addition polymerisation of ethene monomers. Under high pressure and in the presence of a catalyst or initiator, ethene molecules undergo free radical polymerisation, linking together to form long chains of polyethylene. The process requires controlled temperature and pressure, and safety precautions include proper ventilation, protective gear, and handling of reactive gases to prevent accidents.

Question 1: Name two common products made from polymers produced by addition polymerisation.

Answer: Plastic bags and bottles, PVC pipes, or food packaging films.

Question 2: Discuss one advantage and one disadvantage of polymers made through addition polymerisation.

Answer: An advantage is that these polymers are lightweight, durable, and versatile. A disadvantage is that they are often non-biodegradable, contributing to environmental pollution.