A-Level Chemistry: Lab Questions; Qualitative analysis of organic functional groups, with verified Answers for New Updates

Equipment • Test tubes. • Test tube rack. • Dropping pipette. Part A: • Heptane • Cyclohexane • Cyclohexene • Limonene Part B: • 1-chlorobutane • 1-bromobutane • 1-iodobutane • Ethanol • Aqueous silver nitrate Method - Part 1: Identification of an alkene For this experiment unknown organic substances must be identified from the following: • Heptane • Cyclohexane • Cyclohexene • Limonene Using the following: • Bromine water 1. For each of the organic substances, in separate test tubes a. Add 10 drops of bromine water to 1 drop of the substance. b. Mix the test tube well so that the contents are mixed thoroughly. c. Record the observations and identify the chemicals using a table. Results - Heptane Remains Orange Results - Cyclohexene Turns colourless. Results - Cyclohexane Two layers form, bottom layer colourless water and the top layer orange. Results - Limonene Turns colourless. Method - Part 1: Identification of a haloalkane. For this experiment unknown organic substances must be identified from the following: 1-chlorobutane, 1-bromobutane, 1-iodobutane. Using the following: Ethanol and Aqueous silver nitrate. 1. In a beaker set up a water bath. 2. For each of the haloalkanes, in a separate test tube: a. Add five drops haloalkane b. Mix it with 1 cm³ of ethanol and the same volume of silver nitrate solution c. Mix the test tube well to ensure that all the contents are mixed well. d. Place the tube in the water bath and record the observation after 3 minutes. Use the following table to identify the unknown haloalkanes. Results - 1-chlorobutane White precipitate forms. Slow reaction. Results - 1-bromobutane Cream precipitate forms. Quick reaction Results - 1-iodobutane Yellow precipitate forms. Very quick reaction. Risk Assessment - Heptane Risk: Highly flammable. Control: No open flames near the experiment, perform experiment in a fume cupboard or well ventilated area and have appropriate fire extinguishers on hand. Risk Assessment - Cyclohexane Risk: Highly flammable, fatal if swallowed. Control: Don't ingest and keep away from an open flame. Risk Assessment