BRAINCAKEMinimising Errors and Uncertainties
Once you know where the uncertainty in an experiment comes from, you can suggest specific improvements. There are four main strategies.
1. Use more precise apparatus. Choose equipment with smaller divisions or a smaller tolerance: a burette or pipette instead of a measuring cylinder, a balance reading to 0.001 g instead of 0.01 g, or a thermometer read to 0.1 °C instead of 1 °C.
2. Measure larger quantities. For the same apparatus, a larger reading gives a smaller percentage uncertainty. Doubling the mass weighed halves its percentage uncertainty. In a titration, a titre of about 25 cm3 is better than 10 cm3, which can be achieved by changing the concentrations used. In an enthalpy experiment, a larger temperature change can be obtained by using more concentrated solutions.
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Key terms in this lesson
- calorimeter
- An insulated container used to measure the temperature change of a reaction so as little heat as possible is lost to the surroundings.
- anomalous result
- A measurement that does not fit the pattern of the other repeats and is usually discarded before taking a mean.
More in Errors and Uncertainties
- Uncertainty
- Percentage Uncertainty
- Adding Uncertainties
- Adding Percentage Uncertainties
- Percentage Yield
- Atom Economy
- Example Calculation - 1
- Example Calculation - 2
All 14 lessons in Errors and Uncertainties · All Edexcel AS-level Chemistry topics