Turn over 3 4 This question is about alkenes with the molecular formula C5H10 . (a) Draw the skeletal formulae of three branched chain alkenes with the molecular formula C5H10 . (3) 4 (b) Which of these compounds would form pent-2-ene only, when reacted with concentrated phosphoric acid, H3PO4? (1) A CH3CH(OH)CH(CH3)2 B CH2(OH)CH2CH2CH2CH3 C CH3CH2CH2CH(OH)CH3 D CH3CH2CH(OH)CH2CH3 (c) Pent-2-ene reacts with hydrogen bromide, HBr, to form two bromoalkanes. Complete the diagram to show the mechanism for the formation of 2-bromopentane in this reaction. Include curly arrows, and relevant lone pairs and dipoles. (4) H Br Turn over 5 (d) A sample of pent-1-ene, with a mass of 1.33 g, is warmed to 60 °C in a sealed container. The volume of the container is 500 cm3. Calculate the pressure inside the container. Include units and give your answer to an appropriate number of significant figures. [Gas constant (R) = 8.31 J mol−1 K−1] (4) (Total for Question 4 = 12 marks)