Name______Per____Date_____

CONDUCTIVITY

LAB ACTIVITY

Prelab. Activity

  1. Define ionic compounds
  1. List properties of ionic compounds
  1. Define molecular compounds
  1. List properties of molecular compounds
  1. Define electrolytes, strong electrolytes, and weak electrolytes
  1. Define nonelectrolytes

Purpose

Show the difference between electrolytes and nonelectrolytes.

Materials

3 D-cell batteries, 5 15-cm length of bell wire with ends scraped bare, clear plastic cap or beaker, distilled water, tap water, vinegar, sucrose (sugar), sodium chloride (table salt), sodium bicarbonate (baking soda).

Procedure

  1. Connect the batteries together by connecting the bare end of a wire to the positive terminal of the battery and the bare end of the other wire to the negative terminal.
  2. Connect the battery assembly to the light bulb using a wire.
  3. Do not close circuit! (It means that you have to leave 2 bare ends: one coming from the battery assembly, the other – from the light bulb).
  4. Check whether the battery assembly works by touching two bare ends together. (If the light bulb glows then it works!)
  5. Half fill the cup (or beaker) with distilled water. Hold the bare ends of the wires close together (but not touching each other) in the water. If the light bulb doesn’t glow then look for the production of bubbles. It is a sign that the solution conducts electricity.
  6. Repeat step 5 with tap water.
  7. Repeat step 5 with vinegar.
  8. Repeat step 5 with a concentrated solution of sucrose.
  9. Repeat step 5 with a concentrated solution of sodium chloride.
  10. Repeat step 5 with a concentrated solution of baking soda.

Analysis and conclusions

  1. What solutions produce bubbles of gas (or glow a bulb)? Explain why?
  1. Which solution is the strongest electrolyte? Explain why?
  1. Which solution is the weakest electrolyte? Explain why?
  1. What solutions did not produce bubbles of gas (or glow a bulb)? Explain why?
  1. Would you expect the same results if
  2. you used only one battery? Explain your answer.
  1. you used six batteries? Explain your answer.