Combustion and substitution of alkanes, addition reactions of alkenes (hydrogenation, halogenation, hydration), the test for unsaturation, and how the properties of hydrocarbons relate to their uses.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Alkanes like methane are quite unreactive, yet alkenes react readily. The reason is a single extra bond: the C=C double bond.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Compare a saturated alkane with the planar C=C double bond of an alkene.
Copy these into your notebook in your own words — that is how they stick.
Complete: CO₂ + H₂O; incomplete: CO / C + H₂O.
Saturated; unreactive; substitution with halogens in UV light.
Unsaturated; addition reactions.
Ni, ~150 °C.
Br₂ decolourised at room temperature.
Steam, H₃PO₄, ~300 °C, 60 atm → ethanol.
Bromine water decolourised; acidified KMnO₄ purple → colourless.
Alkanes: fuels, solvents; alkenes: polymers, alcohols.
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8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (16 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [16 marks]
Propane, C₃H₈, and propene, C₃H₆, are hydrocarbons.
(a) (a) Write a balanced equation for the complete combustion of propane. [2]
(b) (b) State two products of incomplete combustion of propane. [2]
(c) (c) Describe a chemical test to distinguish propane from propene, stating the observations. [3]
(d) (d) Write equations for the reactions of propene with (i) hydrogen and (ii) bromine, and name the type of reaction. [4]
(e) (e) Write an equation for the reaction of methane with chlorine and state the condition and type of reaction. [3]
(f) (f) State one use of alkanes and one of alkenes. [2]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.