Completed by 20 th November 8 weeks till exam But… Additional Applied Science as well 5 lessons a week = 20 lessons –Products from oil –Plant oils –The Changing World (Earth Science)
Recap on what we know Stuff we know about chemistry from KS3 and Year 10 1 min to answer each question 1 mark per question
Products from oil Cracking Hydrocarbons What is a hydrocarbon? Molecules made up of just Hydrogen and Carbon Crude oil = mixture of hydrocarbons Can be separated using fractional distillation
It’s a cracker Fractional distillation –Products are long-chain hydrocarbons –Thick and gloopy –Very high boiling point –No good as fuel ‘Cracking’ – breaks down long chains to smaller useful molecules = fuels Uses heat and a catalyst
Heavy fraction from crude oil is heated Hydrocarbon Gas Passed over hot catalyst Thermal Decomposition Smaller useful molecules Catalytic cracking
How do we know? Test our products –Burning Alkanes burn cleanly (used as fuel) Alkenes produce a smokey flame and soot –Bromine water Alkanes have no spare bond – no change Alkenes have a spare bond to bong to the bromine so the water turns clear.
Kane or Kene? Cracking produces different types of molecule Decanepentane + propene + ethene Product 1 is pentane –Pent- means 5 –-ane shows its an alkane –C n H 2n+2 Saturated hydrocarbon –It has as much hydrogen as possible
Kane or Kene? Cracking produces different types of molecule Decanepentane + propene + ethene Product 2 is propene –Pro- means 3 –-ene shows its an alkene –C n H 2n Un-saturated hydrocarbon –Contain a double bond
Cracking Hydrocarbons 1.Cracking a hydrocarbon makes two new hydrocarbons, A and B. When Bromine water is added to A, nothing happens. Bromine water added to B loses its colour. Which is the saturated hydrocarbon, and why?
Cracking Hydrocarbons 2.a) An alkene molecule with one double bond contains 7 carbon atoms. How many hydrogen atoms does it have? Write its formula. b) Decane (with 10 carbon atoms) is cracked into octane (8 carbon atoms) and ethene. Write balanced equation for this reaction.