11.5. Alkenes
A subsection of Chemistry, 0620, through 11. Organic chemistry
Listing 10 of 149 questions
This question is about hydrocarbons. State the meaning of the term hydrocarbon. Propene, C3H6, can be made from long-chain alkanes such as dodecane. Dodecane contains 12 carbon atoms. Deduce the molecular formula of dodecane. Name the type of reaction that occurs when long-chain alkanes are converted into shorter chain alkenes. Propene is an unsaturated hydrocarbon. Propene reacts with bromine. State the meaning of the term unsaturated. Write the molecular formula of the product formed when propene reacts with bromine. A styrene molecule is represented as shown in . C C6H5 H C H H The molecular formula of styrene is C8H8. Determine the empirical formula of styrene. Styrene can be polymerised into poly. State the type of polymerisation that occurs when styrene is converted into poly. Draw the structure of one repeat unit of poly. Include all of the atoms and all of the bonds. The C6H5 group should be represented as C6H5.
0620_w24_qp_43
THEORY
2024
Paper 4, Variant 3
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The alkenes are a series of unsaturated hydrocarbons. They have the general molecular formula CnH2n. Deduce the molecular formula of an alkene which has a relative molecular mass of 126. Show your working. The structural formula of propene is drawn below. C H H H C H C H H Draw a diagram showing the arrangement of the valency electrons in one molecule of this covalent compound. Use x to represent an electron from an atom of carbon. Use o to represent an electron from an atom of hydrogen. Draw the structure of the polymer formed from propene Bond energy is the amount of energy, in kJ, which must be supplied to break one mole of the bond. bond bond energy in kJ / mol H — H +436 C C +610 C — C +346 C — H +415 Use the data in the table to show that the following reaction is exothermic. C H H H H H C H C + → H H C H H H H C H H C H H This question is concerned with some of the addition reactions of but-1-ene. Name the product formed when but-1-ene reacts with water. Complete the equation. CH3 — CH2 — CH CH2 + Br2 → Deduce the formula of the compound which reacts with but-1-ene to form 1-iodobutane.
0620_w11_qp_33
THEORY
2011
Paper 3, Variant 3
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