chemistry Lab 4,5, & 7

Experiment 1The Chemistry of Fireworks Experiment Inventory

Materials 5 mL Calcium Chloride Solution (CaCl2)

5 mL Lithium Chloride Solution (LiCl)

5 mL Potassium Chloride Solution (KCl)

5 mL Sodium Chloride Solution (NaCl)

Matches

Modeling Clay

3 Birthday Candles

Labware 4 Inoculating Loops

EXPERIMENT 1: THE CHEMISTRY OF FIREWORKS In this experiment, the flame from a birthday candle is the outside energy source. The flame emits a broad range of energy, but the electrons of the atom being heated will absorb only specific amounts of energy.

LAB SAFETY: Wear your safety glasses and choose an area that is well-ventilated (yet not windy), and have a fire extinguisher nearby. The candle should be on a flat surface. Matches, chemicals, and candle wax can cause a fire or burns to skin, clothing, or lab materials. Do not place any body part, loose clothing, or other flammable items in or near the flame. Never leave any burning fuel unattended!

PROCEDURE

1. Place a round piece of clay on the straight end of each inoculating loop. This will act as a holder.

2. Place in order the LiCl, NaCl, KCl, and CaCl2 solutions. Set one inoculating loop next to each sample.

3. Stabilize one birthday candle by placing the base of it in a piece of clay that is about 1 inch by 1 inch by 1 inch. The candle should stand freely and vertically (Figure 11).The other two candles are to be used if the first one burns down to the clay.

4. Use the matches to light the stabilized birthday candle. Hold the inoculating loop for the LiCl at the very end of the non-looped end in order to avoid burns. Heat the looped end in the candle flame until its loop is faintly orange and any coating is burned off (Figure 11).

CAUTION: Lit matches and candles can cause a fire or burns to skin and/or clothing if the flame comes into contact with skin or clothes. Be sure you have your safety glasses on!

5. Dip the loop into the LiCl solution.

Figure 11: Experiment setup and flame technique.

CAUTION: The loop will remain extremely hot for several minutes following being in the flame. Do not touch the loop!

6. Bring the looped end of the inoculating loop into the flame. Make observations about what is happening, especially any color changes.

Hint: The color change will be most apparent around the edges of the flame. You may have to try this a few times to see the color change.

7. Extinguish the candle, and record your observations in Table 1 on the Experiment 1 Data Sheet.

8. Repeat Steps 4–7 for each of the other three solutions. Use a different inoculating loop for each one.

9. When you’re done, take a photo of your experiment set up. Remember to include your name and lab access code handwritten in the background of the photo. To clean up, you may throw away the inoculating loops after they have cooled to room temperature.