Paper 1 Required practicals

Give the formula to calculate uncertainty

Uncertainty = +- range / 2

Required practical 1:

• Making soluble salts

• Measure acid in a beaker

• Heat the acid gently using a bunsen burner, tripod and gauze

• Using a spatula, add small amounts of insoluble base until it is in excess (stir with a glass rod)

• Filter using filter paper and funnel

• Pour solution into evaporating basin

• Evaporate solution using a bunsen burner until it reaches crystallisation point; crystals begin to form

• Take off the heat and leave in a cool, dry place for at least 24 hours

• Gently pat the crystals dry with filter paper

Required practical 2:

• Carrying out a titration

• Using a pipette, measure and add a known volume of alkali to a conical flask

• Place the conical flask on a white tile

• Fill the burette with acid using a funnel

  • Don’t pour from above head height

• Record the initial reading of acid in the burette

  • From the miniscus

• Add 5 drops of indicator to the conical flask

  • Eg. methyl orange: acid red, neutral+ yellow

  • Eg. phenolphthalein: alkali pink, neutral+ colourless

• Add the acid drop by drop from the burette

• Swirl the conical flask

• Stop when there has been a colour change

• Record the final reading of the acid in the burette and calculate the volume that has been added to the conical flask

Required practical 3:

• Electrolysis

• Pour copper chloride solution into a beaker

• Add the lid and insert carbon graphite (inert) electrodes through the holes, making sure the electrodes don’t touch each other

• Attach crocodile clips to the electrodes and connect the rods to the DC terminals of a low voltage power supply

• Turn the power supply on

• Record observations at each electrode

(Chemical tests)

Required practical 4:

• Investigating the variables that affect temperature changes in reactions

• Place a polystyrene cup in a beaker (to keep it balanced)

• Add acid into the cup

• Measure and record the temperature of the acid

• Add alkali to the cup

• Quickly put a lid on the cup and gently stir the solution with a thermometer through the hole in the lid

• When the reading on the thermometer stops changing, record the temperature

• Repeat the steps by changing variables

Control variables:

• Volume of solutions

• Concentration of solutions