- A student is analysing a sample of water. To determine its density, the student measures the volume with a measuring cylinder and the mass with an electronic balance.
(a) Identify one way to ensure that the volume is read accurately. [1]
The following data are collected:
Volume = (10.6 ± 0.2) cm³
Mass = (10.82 ± 0.01) g
(b) (i) Calculate the density of the sample and its absolute uncertainty. [2]
(ii) State your answers in kg m⁻³ and with correct precision. [1]
(Question 1 continued)
When the density was measured, the sample was at 35°C. The student has a graph that shows the variation with temperature of the density of pure water.
(c) Suggest whether the water sample can be considered pure. [2]