C1 d-f

C1 d-f

1. cd

   • Hydrocarbons are made of carbon and hydrogen only
   • Alkanes and alkenes are separate families of hydrocarbons
   • Alkanes are saturated as they only have single covalent bonds between the carbons.
   • Alkenes are unsaturated as they contain at least one double covalent bond in the molecule
   • A double bond is made 2 pairs of electrons
   • Alkenes react with orange bromine water to form a colourless dibromocompound. This is an addition reaction.
   • Small alkene molecules react to form long polymer chains.
   • alkane – CnH2n+2
   • alkene CnH2n
   • alkene reacts with bromine water and turns it colour less
   • small molecule with a double bond is known as a monemor and a polymere is a long chain of monemors
   • additional polermisation occurs when a double bond is broken and then added to another molecule
   • alkanes: methane, ethane, propane and butane
     • alkenes: Ethene, propene, butene

2. ce

   • Carbon atoms in polymer chains are linked by strong covalent bonds
   • Polymer chains are either linked together by weak intermolecular bonds or strong covalent bonds
   • Goretex is a waterproof but breathable fabric Goretex is a laminate of nylon and PTFE layers

3. Cf

   • . Chemical changes occur when a new substance is made and when the process is irreversible. Cooking is therefore a chemical change.
   • Protein molecules change shape when heated: this is called denaturing.
   • Antioxidants, food colours, flavour enhancers and emulsifiers are all food additives
   • Emulsifiers have a hydrophobic tail and a hydrophilic head
   • Baking powder contains sodium hydrogencarbonate which decomposes on heating to form carbon dioxide. This process is called a thermal decomposition

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