Practical skills

• Weighing by difference involves weighing the substance in a weighing boat using a mass balance. Transfer to a beaker and then reweigh the empty weighing boat to find the mass transferred.
• When making a solution up to a certain volume, use a pipette for the last few drops to ensure you do not overshoot the graduated mark.
• If solution A (usually alkali) is titrated against solution B (usually acid), solution A is in the conical flask and solution B is in the burette.
• To calibrate a pH probe, place the probe in a standard buffer solution and record the pH reading. Repeat for multiple buffer solutions and produce a calibration curve.
• Concordant results are results within 0.1 cm^3 of each other.
• The uncertainty of a reading (one judgement) is +/- 1/2 the resolution.
• The uncertainty of a measurement (two judgements) is +/- the resolution.