11.5. Alkenes
A subsection of Chemistry, 5070, through 11. Organic chemistry
Listing 10 of 74 questions
shows the displayed formula of compound A. H H H H H H H C C C C O H On , draw a circle around the functional group that reacts with aqueous bromine. Describe the colour change when excess compound A is added to a few drops of aqueous bromine in a test tube. colour of aqueous bromine colour after addition of compound A Deduce the molecular formula of compound A. Compound A is a liquid at room temperature. Describe the motion and separation of the particles in a liquid. motion separation shows the structure of compound B. H H H H H H H C C C C H Compound B is polymerised. Draw two repeat units of the polymer formed when compound B is polymerised. Describe two environmental challenges caused by the disposal of plastics.
5070_w23_qp_22
THEORY
2023
Paper 2, Variant 2
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This question is about alkanes and alkenes. But-1-ene belongs to the alkene homologous series. Members of the same homologous series differ from one member to the next by a –CH2– group and have similar chemical properties. State two other characteristics of a homologous series. shows the displayed formula of but-1-ene. H C C C H H H H H H H C Explain how shows that but-1-ene is an unsaturated compound. Give the structural formula of but-1-ene. Draw the displayed formula of an isomer of but-1-ene. Undecane, C11H24, is present in the kerosene/paraffin fraction from the distillation of petroleum. Give one use of the kerosene/paraffin fraction. When undecane is cracked, shorter hydrocarbon molecules are formed. Construct the symbol equation for a reaction in which undecane is cracked and the only products are butane, propene and ethene. Propane reacts with chlorine to form chloropropane and one other product, X. C3H8 + Cl 2 C3H7Cl + X Name product X. State the essential condition for this reaction. Ethene reacts with bromine at room temperature. shows the displayed formulae of the reactants and product. C H H H H C H C C H + Br Br Br H H Br Calculate the enthalpy change of this reaction in kJ / mol. Use the bond energies in Table 4.1. Table 4.1 type of bond C=C C–H Br–Br C–C C–Br bond energy in kJ / mol enthalpy change = kJ / mol Describe the colour change when a sample of excess ethene is added to a few drops of aqueous bromine. from to
5070_w24_qp_21
THEORY
2024
Paper 2, Variant 1
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