Required Practicals Flashcards
How do you carry out making salts from copper oxide?
You would carry out making salts from copper oxide by:
1) . Measure acid (e.g sulphuric acid) into a beaker
2) . Heat the acid gently using a bunsen burner
3) . Add small amounts of of insoluble base (e.g copper oxide until it is in excess, when no more reacts)
4) . Filter the solution to remove the excess insoluble base.
5) . Evaporate the solution using a water bath until crystals start to form
6) . Leave the crystallising dish in cool place for at least 24 hours
7) . Gently pat the crystals dry between two pieces of filter paper.
How do you carry out electrolysis from copper oxide?
You would carry out electrolysis from copper oxide by:
1) . Add about 50 cm³ of salt solution into a beaker
2) . Add the lid and insert carbon rods (electrodes) through the holes. The rods must not touch each other.
3) . Attach crocodile rods to the electrodes. Connect the rods to the dc (red and black) terminals of a low voltage power supply
4) . Switch the power supply on
5) . Record observations at each electrode.
How do you carry out neutralisation?
You would carry out neutralisation by:
1) . Use the pipette to measure 25cm³ of alkali into a conical flask
2) . Stand the conical flask onto a white tile
3) . Fill the burette with acid using a funnel.
4) . Record the initial reading of acid in the burette.
5) . Add a small amount of indicator (e.g phenolphthalein, methyl orange, or litmus) to the conical flask.
6) . Slowly open the burette tap while swirling the conical flask
7) . Add acid drop-by-drop near the endpoint
8) . Close the burette when a colour change occurs in the indicator (phenolphthalein [pink → colourless], methyl orange [ yellow → red], litmus [blue → red].
9) . Record the final reading of an acid in the burette and calculate the titre
10) . Repeat until you have two concordant results (within 0.1 cm³ of each other).
How do you carry out temperature changes in a required practical?
You would carry out temperature changes by:
1) . Measure 25 cm³ of acid into a polystyrene cup
2) . Stand the cup inside the beaker (this will make it more stable).
3) . Measure and record the temperature of the acid
4) . Measure 5 cm³ of alkali and add it to the polystyrene cup
5) . Put a lid on the cup and gently stir the solution with the thermometer through the hole in the lid.
6) . When the reading on the thermometer stops changing, record the temperature
7) . Repeat steps 4 and 5 to add further amounts of 5 cm³ of alkali to the cup. A total of 40 cm³ needs to be added
8) . Repeat steps 1-7
9) . Calculate the mean maximum temperature reached for each of the sodium hydroxide volumes
How do you carry out chromatography?
You carry out chromatography by doing this scientific method:
1) . Draw a horizontal pencil line 2 cm from a short edge of the chromatography paper. Mark pencil spots at equal intervals across the line. Keep at least 1 cm away from each end
2) . Use a glass capillary tube to put a small spot of each colouring on the pencil spots. Label each spot in pencil
3) . Pour water into the beaker to a depth of no more than 1 cm
4) . Suspend the paper in the beaker so that the bottom edge of the paper dips into the water
5) . Wait for the water solvent to travel at least three quarters of the way up the paper. Remove the paper and draw another pencil line on the dry part of the paper as close to the wet edge as possible
6) . Hang the paper up to dry thoroughly
7) . Calculate the Rf values for each spot.
How do you obverse colour changes in rates of reaction?
You obverse colour changes in rates of reaction by:
1) . Measure 10 cm³ sodium thiosulfate solution into the conical flask
2) . Measure 40 cm³ water and add it to the conical flask
3) . Put the conical flask on the black cross
4) . Measure 10 cm³ of dilute hydrochloric acid
5) . Add the acid to the flask. At the same time, swirl the flask gently and start the stopcock
6) . Look down through the top of the flask. Stop the clock when you can no longer see the cross and record the time taken.
7) . Repeat steps 1-6 four times, using different volumes of sodium thiosulfate and water. This will change the concentration of sodium thiosulfate
8) . Repeat steps 1-7 twice more
9) . Calculate the mean time for each of the sodium thiosulfate concentrations.
How do you analyse a sample of water in water purification?
You would analyse a sample of water by doing this scientific method:
1) . Use universal indicator or a PH probe to test the PH of the water
2) . Measure and record the mass of an empty evaporating basin
3) . Pour 10 cm³ of water into it and evaporate the water using a Bunsen burner until the majority of the water has evaporated
4) . Once the evaporating basin is cool, reweigh and record the change in mass. Calculate the mass of dissolved solids in the water.
How do you do the flame test for metal ions?
You could do the flame test for metal ions by:
1) . Clean the nichrome wire by dipping it in dilute hydrochloric acid
2) . Dip the nichrome wire into the unknown solution
3) . Hold the tip of the wire in a blue Bunsen burner flame
How would you do the sodium hydroxide test for metal ions?
You are able to do the sodium hydroxide test for metal ions by:
1) . Add a few drops of sodium hydroxide solution to your unknown solutions
2) . If you form a white precipitate, add more sodium hydroxide until it is in excess.
How do you do the carbonate ion test?
You do the carbonate test by:
1) . Place a little limewater in a clean test tube
2) . Add a little dilute hydrochloric acid to the unknown solution
3) . If you see bubbles, transfer the gas produced to the limewater using a pipette or delivery tube.
How would you carry out the sulphate ion test?
You carry out the sulphate ion test by:
1) . Add a few drops of dilute hydrochloric acid to the unknown solution
2) . Add a little barium chloride solution
How would you carry out the halide ion test?
You carry out the halide ion test by:
1) . Add a few drops of dilute nitric acid to the unknown solution
2) . Add a little silver nitrate solution.
How would you purify a sample of water by distillation?
You purify a sample of water by distillation by:
1) . Place a water sample in a conical flask and set up the apparatus for distillation
2) . Heat the water gently using a Bunsen burner untick it boils. Then reduce the heat so the water boils gently
3) . Collect around 1 cm depth of water in the cooled test tube, the stop heating
4) . Analyse the water you have distilled with cobalt chloride paper.
How do you measure the volume gas produced?
You measure the volume gas produced by:
1) . Measure 50 cm³ of 2 mol/dm³ hydrochloric acid using one of the measuring cylinders. Pour the acid into the 100 cm³ conical flask
2) . Set up the apparatus.
3) . Add a 3 cm strip of magnesium ribbon to the flask and put the bung back into the flask. At the same time, start the stopcock
4) . Record the volume of hydrogen gas given off every 10 seconds. Stop when no more gas is given off
5) . Repeat steps 1-4 using 1 mol/dm³ hydrochloric acid
6) . Plot a graph of ‘volume of gad produced’ against ‘time’. Draw two curves, one for each concentration of acid.
