Fill in the three omitted entries in Table 2.1.
The parts of the thermometer used in Experiment 3 are shown in Fig. 2.1. The liquid levels inside the thermometer are not shown. Finish Fig. 2.1 by drawing the liquid level to represent the starting temperature in Experiment 3 and the highest temperature reached in Experiment 3.
On the grid in Fig. 2.2, draw a graph of temperature rise against volume of Q. Plot $(0,0)$ because there is no temperature rise when no Q is added, plot the temperature rises and volumes of Q from Table 2.1, draw a straight line of best fit for the first four points, draw a straight line of best fit for the last three points, and extend the lines until they meet.
The place where the two lines cross shows the volume of Q that exactly neutralises $25.0\,\text{cm}^3$ of P. Determine the volume of Q at the crossing point of the two lines on the graph.
P is $1.25\,\text{mol dm}^{-3}$ aqueous sodium hydroxide. Use your answer to (d) to find the concentration of sulfuric acid in Q. $$2\text{NaOH} + \text{H}_2\text{SO}_4 \rightarrow \text{Na}_2\text{SO}_4 + 2\text{H}_2\text{O}$$
Describe and explain how the gradient of the straight line for the first four points on the graph would change if a metal cup were used instead of a plastic cup.
A burette may be used instead of a measuring cylinder to measure the volume of water in these experiments. Suggest how this improves the experiments.
State the dependent variable in this set of experiments.