5.14 describe how long-chain alkanes are converted to alkenes and shorter-chain alkanes by catalytic cracking, using silica or alumina as the catalyst and a temperature in the range of 600-700 degrees celsius

5.14 •conditions for cracking: heat + catalyst

                  1. heat mineral wool soaked in paraffin 

                  2. after a few seconds, heat the alumina or silica catalyst. Alternate between the two until the paraffin vaporises and the catalyst glows red

                  3. the heated paraffin cracks as it passes over the heated catalyst 

                  4. small alkanes collect at the end of the boiling tube, while alkene gases travel down the delivery tube through water, into the glass jar

                                •it is heated to 600-700 degrees celsius