Passage V

A solution is a mixture of at least two substances. The solvent does the dissolving and the solute is dissolved by the solvent.

Some solutions containing solutes, called electrolytes, can conduct electricity because they can carry an electric charge when in solution; whereas nonelectrolytes cannot carry an electric charge. An ammeter is a device used to measure the current carried by a solution (see Figure 1).

The following experiments were performed to test the hypothesis that either increasing the amount of solute or the temperature of the solution will increase the solution's conductivity.

Experiment 1

The solutions consisted of 5.0 grams (g) of each solute dissolved in 100 milliliters (mL) of water at 20°C. The water was also tested without any solute. The results are shown in Table 1.

Experiment 2

Experiment 1 was repeated, except the amount of solute of each solution was increased to 10.0 g in 100 mL of water at 20°C. The results are shown in Table 2.

Experiment 3

Experiment 2 was repeated at 50°C. The results are shown in Table 3.