Question 1: Addition polymerisation is a chemical process where monomers with double bonds link together to form long chain polymers without the loss of any small molecules. This process is typically initiated by free radicals, heat, or catalysts.

Answer: Addition polymerisation involves the linking of monomers with double bonds to form polymers, usually initiated by free radicals or other catalysts, without losing any small molecules.

Question 1: Define addition polymerisation.

Answer: A polymerization process where monomers with double bonds join together without losing any atoms, forming long chain polymers.

Question 2: Name one common monomer used in addition polymerisation and the polymer it forms.

Answer: Ethene (ethylene) forms polyethene (polyethylene).

Question 3: Explain the role of a free radical in addition polymerisation.

Answer: A free radical initiates the reaction by breaking the double bonds in monomers, creating reactive sites for chain growth.

Question 1: If 0.5 moles of ethene monomers are polymerized, how many moles of ethene molecules are involved in the process? (Assume complete reaction).

Answer: 0.5 moles

Question 2: Calculate the mass of ethene (molecular weight = 28 g/mol) required to produce 14 grams of polyethylene, assuming a 1:1 molar ratio in the polymer chain.

Answer: 14 g / (28 g/mol) = 0.5 mol of ethene

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

Answer: Use a sealed reaction vessel with a catalyst or initiator like a peroxide, apply heat or UV light to generate free radicals, and ensure safety measures such as gloves and goggles are used.

Question 2: Identify two safety precautions that should be observed during the polymerisation process.

Answer: Wearing protective gloves and goggles; ensuring proper ventilation to avoid accumulation of flammable gases.

Question 1: A sample of polyethylene was produced using 2 moles of ethene monomers. The resulting polymer was found to weigh 560 grams. Determine the approximate molecular weight of the polymer chain, assuming all monomers contributed equally.

Answer: 560 g / 2 mol = 280 g/mol

Question 2: Based on the data, what can you infer about the degree of polymerization of the sample?

Answer: The degree of polymerization is approximately 10, since 280 g/mol is about 10 times the molar mass of ethene (28 g/mol).

Question 1: Explain how addition polymerisation differs from condensation polymerisation. Include in your answer the type of monomers involved, the reaction mechanism, and the by-products formed.

Answer: Addition polymerisation involves monomers with double bonds linking together without losing any atoms, typically initiated by free radicals, resulting in long chain polymers. It does not produce by-products. In contrast, condensation polymerisation involves monomers with two functional groups, and as the chain grows, small molecules such as water or HCl are released as by-products. The mechanism includes stepwise reactions with functional group interactions.

Question 1: Name two products made from polyethylene and describe their uses.

Answer: Plastic bags for packaging and containers for food storage.

Question 2: Discuss the environmental impact of polymers produced via addition polymerisation and suggest one way to mitigate this impact.

Answer: Polymers such as polyethylene are non-biodegradable and can contribute to pollution and landfill buildup. To mitigate this, promoting recycling and development of biodegradable polymers can help reduce environmental harm.