Uncertainty in measurements: 4.3.1 Chemical measurements, conservation of mass and the quantitive interpretation of chemical equations: AQA Q&A: GCSE (9:1)

23.5°C

A student reads a value of 23.0 degrees from a thermometer. The thermometer has an uncertainty of ₊⁻0.5°C. What is the maximum possible temperature for this reading?

Thermometer B has a higher resolution

A student has a choice of thermometers. Thermometer A reads to the nearest 0.5°C, and thermometer B reads to 2 decimal places. Which statement can be deduced from this information?

15.65

What is the temperature reading on this thermometer?

24.25

In an experiment the following four volume measurements were taken:

24.5 cm³, 24.0 cm³, 23.5 cm³, 25.0 cm³

Calculate the mean for these measurements

1.5 cm³

In an experiment the following four volume measurements were taken:

24.5 cm³, 24.0 cm³, 23.5 cm³, 25.0 cm³

Calculate the range for these measurements

0.75 cm³

In an experiment the following four volume measurements were taken:

24.5 cm³, 24.0 cm³, 23.5 cm³, 25.0 cm³

Calculate the uncertainty for these measurements

3

In an experiment the following four volume measurements were taken:

24.5 cm³, 24.0 cm³, 23.5 cm³, 25.0 cm³

How many significant figures are these values to?

±0.005 g

A balance is used to record the mass of a substance to 2 decimal places. What is the uncertainty value for this balance?

They are not to the same number of decimal places

A student repeats an experiment three times and records the following temperature changes for the same reaction conditions:

14.5 °C 10°C 9.5°C

What is wrong with the way the results have been recorded?

11.3 °C

A student repeats an experiment three times and records the following temperature changes for the same reaction conditions:

14.5 °C 10°C 9.5°C

Calculate the mean for the results, using all the readings, and record your answer to three significant figures

9.8 °C

A student repeats an experiment three times and records the following temperature changes for the same reaction conditions:

14.5 °C 10°C 9.5°C

Calculate the mean for the results, using only results that lie within 1°C of each other. Give your answer to two significant figures

± 2.5 °C (previously written 5 but prob. wrong)

A student repeats an experiment three times and records the following temperature changes for the same reaction conditions:

14.5 °C 10°C 9.5°C

Calculate the uncertainty for these values