practical skills in all papers

• for smoothing boiling by producing smaller bubbles

• water bath as some compounds are flammable • gloves as some compounds are corrosive • fume cupboard to avoid breathing in harmful chemicals • anti-bumping granules to ensure smooth boiling by reducing size of bubbles

add a stopper/bung

drying agent, to remove water

• Weigh out 0.20 g of the metal carbonate, and record its mass to two decimal places. • Tip the metal carbonate into a 100 cm3 beaker and add about 50 cm3 of water. • Wash any powder on the weighing boat into the beaker using distilled water. • Stir the solid carbonate with a glass rod until it has completely dissolved. • Pour the solution that you have just made into a 100 cm3 volumetric flask. All of the solid must be dissolved before you do this. Wash any solution remaining in the beaker into the volumetric flask, and then wash any liquid on the funnel into the flask as well. • Finally, make the solution up to exactly 100 cm3 by adding distilled water until the bottom of the meniscus is resting on the 100 cm3 line when observed at eye level.

• Use a pipette to transfer exactly 25 cm3 of your metal carbonate solution from the volumetric flask to a clean dry conical flask. • Add 5 drops indicator to the conical flask. - Prepare a table for your results. • Then prepare a burette containing a 0.0500 mol dm-3 solution of hydrochloric acid. • Make sure that there is no air-bubble below the tap, and that the bottom of the meniscus is on or below 0.00 cm3. • Record the initial volume of hydrochloric acid in your table. • Add hydrochloric acid from the burette until the indicator changes colour. • Record your burette reading in the results table to two decimal places. The second decimal should be either 0 or 5. • Clean out the conical flask, and repeat the titration as before. • You should add the acid slowly, ideally one drop at a time, as you approach the end point. • You should continue to repeat the titration until you have obtained at least two concordant results

Reaction 1 (anhydrous copper(II) sulphate, CuSO4(s), Mr = 159.6) - Carefully measure out 25 cm3 of distilled water into a polystyrene cup. - Weigh out 3.20 g of anhydrous copper(II) sulphate powder. - Stir the water in the cup, and start the clock. Measure the temperature to the nearest 0.1 oC every 30 seconds for 2.5 minutes. - at exactly 3 minutes, add the anhydrous copper(II) sulphate to the water. Stir thoroughly, but do not attempt to measure the temperature at this time. - Now measure the temperature at 3.5 minutes, and at further half-minute intervals until a total time of 10 minutes is reached. - Make sure that all results are clearly recorded in a suitable table. Reaction 2 (hydrated copper(II) sulphate, CuSO4.5H2O(s), Mr = 249.7) - Carefully measure out 25 cm3 of distilled water into a polystyrene cup. - Weigh out 5.00 g of hydrated copper(II) sulphate crystals. - Now continue with the rest of the method exactly as for reaction 1 above.

• Connect a gas syringe to a boiling tube with a side arm. Make sure that they are both clamped securely. • Weigh out 0.5 g of potassium iodide catalyst, and place it in the boiling tube. • Prepare a water bath: the water should be at a temperature between 15 oC and 55 oC. Position the side-arm tube so that it is in the water bath. • Also stand a test-tube containing 6 to 10 cm3 of 10 volume hydrogen peroxide in the water bath. • Put a thermometer into the hydrogen peroxide and wait for the temperature to stabilise. • When you are ready, record the temperature of the hydrogen peroxide draw 5 cm3 of it into a syringe, inject it through the thin rubber cap into the side-arm tube, and simultaneously start the stop-clock. • Record the volume of oxygen gas produced after 60 seconds. • Repeat the procedure for a different temperature, until you have results for a least three different temperatures.

• Read through the sequence of tests, and then draw a table of your own design in which to record your observations. • Add ten drops of solution A to a clean dry test-tube, then add ten drops of sodium hydroxide and record your observations in the table • Now heat the test tube in a hot water bath for 5 minutes, and at the end of this time, hold a moist indicator above the mouth of the tube. Record any further observations. • Add ten drops of solution A to a second test-tube, and then add ten drops of sulphuric acid and record your observations. • Take another clean dry test tube and add ten drops of solution A. Next add 5 drops of silver nitrate solution and record your observations. • Repeat steps 2 to 4 with solutions B, C and D.

white percipitate

white percipitate

unpleasent smell

white percipitate then dissolves in dilute NH3

cream percipitate then dissolves in conc NH3

yellow percipitate doesnt dissolve in conc NH3

white percipitate

bubbles of CO2

white percipitate

• Place 5 cm3 of ethanol into a pear-shaped flask and add 3-5 anti-bumping granules. • add 5 cm3 of concentrated sulphuric acid in portions of about 0.5 cm3 at a time. • Make sure that the contents of the flask are well-mixed, and cool them by running cold water from a tap over the flask, but take care that no water enters the flask. • Quickly add 6 g of potassium bromide, and set up the apparatus. You must take care that no crystals of potassium bromide are left on the ground-glass joint. • Heat the flask on an air-bath using a low Bunsen flame. • Do not heat the pear-shaped flask directly with the Bunsen flame. The bromoethane will collect under the water in the conical flask as it is distilled out of the reaction mixture. • Remove the delivery tube from the water, and then turn off the Bunsen flame. • If the flame is turned off before removing the delivery tube, water may be sucked into the pear-shaped flask. • In order to collect the bromoethane product, carefully pour away most of the water from the conical flask. Use a dropping pipette remove the remaining water.

• draw a table in which to record your observations. • Add 5 drops of M to a test tube, and then add 5 drops of aqueous bromine. Shake to mix, and then record any observations. • Add 10 drops of M to a test tube, and then add 10 drops of sodium carbonate solution. Observe the tube carefully, and record any significant changes. • Add 10 drops of sulphuric acid to a test tube, and then add 10 drops of potassium dichromate(VI). • Swirl the tube in order to mix the reagents thoroughly and then add 5 drops of M. • Leave the mixture in a beaker of freshly boiled water for five minutes, and then record your observations. • Add 10 drops of Fehling’s solution A to a test tube, and then add 10 drops of Fehling’s solution B. • Swirl the tube until the two solutions are properly mixed, and then add 5 drops of M. - Leave the mixture in a beaker of freshly boiled water for five minutes, and then record your observations. • Repeat steps 2 to 5 with liquids N, O and P. • Use the results of these tests in order to identify the functional groups present in liquids M to P.

reduces lost of liquid droplets

to wash off any residual solution

to avoid messing with end point

drops of acid could fall into burette