Chemical Measurements
Chemistry: Edexcel IGCSE, topic 5.1.15
Chemical Measurements
Every chemical measurement involves some uncertainty.
Uncertainty
- E.g. a digital thermometer is able to measure to a precision of 0.1oC.
- If this thermometer displayed a reading of 35.4oC, the actual temperature could be anywhere between 35.35oC and 35.45oC.
Reducing uncertainty
- The larger the uncertainty, the larger the range of results you should expect.
- This is a reason why it is important to repeat the measurements from experiments several times and calculate an average from them.
Test yourself on Chemical Measurements
If a digital thermometer can measure to a precision of 0.1°C, what is the range of temperatures that a 45.4°C reading can actually be?
A student compares two thermometers used to measure the same sample. Thermometer X has an uncertainty of 0.1°C and Thermometer Y has an uncertainty of 0.5°C. Which thermometer would give the wider range of possible actual temperatures for the same displayed reading?