QUIZ 9a. Oil - Hydrocarbons and Cracking

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   alkane      alkanes      alkene      alkenes      carbon      catalyst      cracking      decomposition      double      econmically      faster      molecule      saturated      single      smaller      thermal      unsaturated      vaporise   
(a) Larger hydrocarbon molecules can be broken down into more useful molecules by a process called . To break the molecules down the hydrocarbons from oil are heated to them and the hot vapours (gases) are passed over a heated to make the process , so it is more efficient. Breaking compounds down by heat in this way is an example of a reaction known as a .

(b) There are several types of hydrocarbons formed in this reaction and the products include alkanes with no double bonds and alkenes which have a carbon-carbon double bond.

(c) CnH2n+2 is the general formula for the series of molecules known as and
CnH2n is the general formula for the series of molecules known as where n is the number of atoms in the .

(d) (i) Image151.gif is an example of an .
(ii) Image925.gif is an example of hydrocarbon called an , which is an molecule because it has a carbon-carbon bond.
(iii) Image931.gif is an example of an .
(iv) Image207.gif is an example of an , a type of hydrocarbon described as a molecule because it has all carbon-carbon bonds.