Question 1: Alkenes are unsaturated hydrocarbons containing at least one carbon-carbon double bond. They can undergo addition reactions that are useful in producing environmentally friendly fuels and plastics. Understanding these reactions helps in developing sustainable chemical processes to combat climate change.

Answer: Alkenes are unsaturated hydrocarbons with one or more C=C double bonds that undergo addition reactions to produce useful materials and reduce environmental impact.

Question 1: Define the term 'alkene'.

Answer: An alkene is a hydrocarbon containing at least one carbon-carbon double bond.

Question 2: Explain why alkenes are considered unsaturated hydrocarbons.

Answer: Because they contain carbon-carbon double bonds, which means they can add more atoms in addition reactions, unlike saturated hydrocarbons with only single bonds.

Question 3: Describe the general mechanism of an addition reaction of an alkene with hydrogen halides.

Answer: The alkene's C=C bond breaks, and a hydrogen atom and a halide atom add across the double bond, forming a halogenoalkane.

Question 1: Calculate the volume of hydrogen gas required to fully hydrogenate 2 moles of ethene at standard temperature and pressure (STP). (Use the reaction: C2H4 + H2 → C2H6)

Answer: Volume = 44.8 litres

Question 1: Design a simple experiment to test the addition of bromine water to an alkene. Include the variables you would control and safety precautions you would take.

Answer: The experiment involves adding bromine water to an alkene sample in a test tube. Variables to control include temperature, concentration of bromine water, and amount of alkene. Safety precautions include wearing safety goggles, gloves, and working in a well-ventilated area to avoid inhaling bromine vapour, which is toxic.

Question 1: A new process uses ethene to produce bio-based plastics that can decompose faster and reduce greenhouse gas emissions. Explain how the addition reactions of alkenes contribute to developing sustainable materials and their impact on climate change.

Answer: Addition reactions of alkenes enable the production of biodegradable plastics from renewable resources. These materials decompose faster in the environment, reducing landfill waste and greenhouse gases associated with traditional plastics, thus helping mitigate climate change.

Question 1: Describe the role of alkene reactions in the development of environmentally sustainable fuels. Include in your answer the types of reactions involved and their significance in reducing carbon emissions.

Answer: Alkene reactions such as hydrogenation are used to produce cleaner-burning fuels by converting unsaturated hydrocarbons into saturated ones, reducing soot and unburned hydrocarbons. Additionally, addition reactions enable the synthesis of biofuels from renewable plant oils. These processes help lower carbon emissions, contributing to efforts against climate change.