C7

• cracking is the process of breaking down large hydrocarbons into smaller hydrocarbons
• a hydrocarbon is a compound made of ONLY hydrogen and carbon
• incomplete combustion occurs when there is a limited supply of oxygen
• an alkane is a hydrocarbon containing only single bonds
• to carryout catalytic cracking, you need a catalyst and heat
• the flammability changes with the length of the alkane because the longer the alkane, the less flammable it is
• to carry out steam cracking, you need heat and steam
• fractional distillation is to separate mixtures with different boiling points
• crude oil is a finite resource because we are using it quicker than it is being formed
• products of incomplete combustion are carbon monoxide and water
• to test for an alkene: add bromine water, stays orange if alkane and changes from orange to colourless if alkene
• viscosity changes with the length of an alkane because the longer the alkane, the more viscous it is
• a finite resource is one that will run out
• products of complete combustion are carbon dioxide and water
• crude oil is made from the remains of ancient marine organisms buried in mud
• long hydrocarbons have a high boiling point because they have more intermolecular forces in between them so more energy is needed to break them
• crude oil is a mixture of hydrocarbons
• steps of fractional distillation: 1. crude oil is heated and vaporised 2. molecules rise up column and cool down 3. different fractions condense at different points
• general products of cracking are shorter alkanes and alkenes
• the first four alkanes are: 1. methane 2. ethane 3. propane 4. butane
• cracking is important because smaller hydrocarbons are more useful and helps meet supply and demand
• the general formula of alkanes are C H
• alkenes are hydrocarbons that contain double bonds
• the boiling point changes with the length of an alkane because the longer the alkane, the higher the boiling point