Question 1: Define an addition reaction in the context of organic chemistry.

Answer: An addition reaction is a chemical process where two reactants combine to form a single product by adding across a double bond in an alkene.

Question 2: Describe the general mechanism of an electrophilic addition reaction of an alkene with hydrogen halides.

Answer: The mechanism involves the alkene's π bond acting as a nucleophile, attacking the electrophilic hydrogen halide, leading to the formation of a carbocation intermediate, followed by the attachment of the halide ion to form the addition product.

Question 3: Explain why addition reactions are important in industrial applications involving alkenes.

Answer: Addition reactions are crucial because they allow the synthesis of various useful compounds, such as plastics, pharmaceuticals, and fuel additives, by modifying the structure of alkenes efficiently.

Question 1: Calculate the volume of hydrogen gas (H2) required to fully hydrogenate 2.5 mol of ethene at standard temperature and pressure (STP). (Use the molar volume of gases = 22.4 L/mol).

Answer: Volume = moles of H2 × molar volume = 2.5 mol × 22.4 L/mol = 56 L

Question 2: An industrial process converts 100 kg of an alkene with a molecular weight of 70 g/mol via an addition reaction. How many moles of the alkene are involved?

Answer: Number of moles = mass / molar mass = 100,000 g / 70 g/mol ≈ 1428.57 mol

Question 1: Describe a safe laboratory procedure for handling hydrogen halides during an addition reaction experiment, considering space exploration applications.

Answer: Use a fume hood to contain fumes, wear appropriate PPE such as gloves and goggles, handle reagents with care to prevent leaks, and ensure proper ventilation to avoid inhalation hazards.

Question 2: Identify the main variable that affects the rate of addition reactions of alkenes in space-based chemical manufacturing.

Answer: The concentration of the reactants, particularly the electrophile or hydrogen source, affects the reaction rate.

Question 1: A spacecraft's on-board chemical system uses ethene to produce a polymer via an addition reaction with a halogen. During testing, the reaction was observed to proceed faster at higher temperatures. Explain why increasing temperature affects the rate of addition reactions.

Answer: Higher temperatures increase the kinetic energy of molecules, leading to more frequent and energetic collisions, which enhances the reaction rate of addition reactions.

Question 1: Explain how addition reactions of alkenes could be utilised in the development of materials for spacecraft insulation and why such reactions are advantageous.

Answer: Addition reactions allow the modification of alkene molecules to produce polymers with specific properties such as heat resistance and durability. These tailored materials are essential for spacecraft insulation, providing protection from extreme temperatures and radiation. The reactions are advantageous because they are efficient, versatile, and can produce high-performance materials suitable for the challenging conditions of space.