aqa A-level chemistry paper 3
Carry out simple test-tube reactions to identify anions. 7 - halide ions- add small volume of nitric acid to
solution followed by silver nitrate solution. different coloured ppt shows different halide ions, add
excess dilute ammonia solution followed by conc ammonia solution to confirm halide ions.
group 7 solid salts- add conc sulphuric acid to potassium halide. record observations, KCl- white misty
fumes, KBr- orange fumes, KI- purple fumes and purple/black solid. test gas with damp blue litmus
paper, all should turn red.
carbonate ions- add dilute HCl to sodium carbonate, collect gas produced and bubble though limewater,
should turn cloudy.
Carry out simple test-tube reactions to identify cations. 2 - group 2- sodium hydroxide. Place 10 drops of
0.1 moldm-3 barium chloride in a clean test tube. add 10 drops of 0.6 moldm-3 of sodium hydroxide.
continue to add NaOH drop wise until in excess. repeat with strontium chloride, calcium bromide and
magnesium chloride. hydroxides get more soluble down the group.
sulphuric acid. repeat first experiment but with sulphuric acid instead, sulphates get less soluble down
the group.
ammonium ions. add ammonium chloride and sodium hydroxide, warm gently. test gas produced with
damp red litmus paper, should turn blue.
column chromatography - stationary phase- column packed with absorbent material such as alumina or
silica gel coated with water. mobile phase- mixture to be separated, added at the top of the column and
allowed to run down.
Distillation of a product from a reaction. Preparation of cyclohexene by the dehydration and distillation
of cyclohexanol. - Pour 20 cm3 of cyclohexanol into a 50 cm3 pear-shaped flask that has been weighed.
Reweigh the flask and record the mass of cyclohexanol. Using a plastic graduated dropping pipette,
carefully add approximately 8.0 cm3 of conc phosphoric acid to the flask, add antibumping granules.
heat gently, distilling any liquid which boils under 100°C. Pour the distillate into a separating funnel and
add 50 cm of saturated sodium chloride solution. Shake the mixture and allow the two layers to
separate. run lower layer into a beaker to leave cyclohexene in funnel. calculate mass to calculate
percentage yield. test for alkene using bromine water.
gas chromatography - stationary phase- solid or solid coated by a viscous liquid such as oil, packed into a
tube. mobile phase- inert carrier gas such as nitrogen
Carry out simple test-tube reactions to identify anions. 7 - halide ions- add small volume of nitric acid to
solution followed by silver nitrate solution. different coloured ppt shows different halide ions, add
excess dilute ammonia solution followed by conc ammonia solution to confirm halide ions.
group 7 solid salts- add conc sulphuric acid to potassium halide. record observations, KCl- white misty
fumes, KBr- orange fumes, KI- purple fumes and purple/black solid. test gas with damp blue litmus
paper, all should turn red.
carbonate ions- add dilute HCl to sodium carbonate, collect gas produced and bubble though limewater,
should turn cloudy.
Carry out simple test-tube reactions to identify cations. 2 - group 2- sodium hydroxide. Place 10 drops of
0.1 moldm-3 barium chloride in a clean test tube. add 10 drops of 0.6 moldm-3 of sodium hydroxide.
continue to add NaOH drop wise until in excess. repeat with strontium chloride, calcium bromide and
magnesium chloride. hydroxides get more soluble down the group.
sulphuric acid. repeat first experiment but with sulphuric acid instead, sulphates get less soluble down
the group.
ammonium ions. add ammonium chloride and sodium hydroxide, warm gently. test gas produced with
damp red litmus paper, should turn blue.
column chromatography - stationary phase- column packed with absorbent material such as alumina or
silica gel coated with water. mobile phase- mixture to be separated, added at the top of the column and
allowed to run down.
Distillation of a product from a reaction. Preparation of cyclohexene by the dehydration and distillation
of cyclohexanol. - Pour 20 cm3 of cyclohexanol into a 50 cm3 pear-shaped flask that has been weighed.
Reweigh the flask and record the mass of cyclohexanol. Using a plastic graduated dropping pipette,
carefully add approximately 8.0 cm3 of conc phosphoric acid to the flask, add antibumping granules.
heat gently, distilling any liquid which boils under 100°C. Pour the distillate into a separating funnel and
add 50 cm of saturated sodium chloride solution. Shake the mixture and allow the two layers to
separate. run lower layer into a beaker to leave cyclohexene in funnel. calculate mass to calculate
percentage yield. test for alkene using bromine water.
gas chromatography - stationary phase- solid or solid coated by a viscous liquid such as oil, packed into a
tube. mobile phase- inert carrier gas such as nitrogen
