Wooden Splints Flame Tests Lab

Name______Date ______

Introduction:

Have you ever seen a fireworks display? Where do all of the colors come from? In this activity, you will investigate the colors of light produced by metal salts. Just as a fingerprint is unique to each person, the color of light emitted by metals heated in a flame is unique to each metal.

A flame test is a procedure used to test for the presence of certain metals in chemical compounds. When the compound to be studied is excited by heating it in a flame, the metal ions will begin to emit light. Certain metal ions will turn the flame very distinctive colors; these colors in turn can help identify the presence of a particular metal in a compound. This technique of using certain chemical compounds to color flames is widely used in pyrotechnics to produce the range of colors seen in a firework display.

Flame Tests Activity

Materials:

▪ Bunsen burner ▪ 250 ml beaker ▪ Wooden splints (7 per group) ▪ An aluminum rectangular container that has the following metal salts in it : ➢ barium chloride ➢ strontium chloride ➢ calcium chloride ➢ copper(II)chloride ➢ sodium chloride ➢ potassium chloride ➢ lithium chloride ➢ 2 Unknown metal salt samples

Procedure:

1. Obtain 9 wooden splints that have been soaking in water. 2. Fill a 250ml beaker about half-full with distilled water that can be obtained from the opaque white container on the front counter. This will be your RINSE beaker. 3. Light the Bunsen burner so that you have the double cone non-luminous flame. 4. Dip the soaked end of one of the wooden splints in one of the metallic salts, then place it in the flame. Observe the color of the flame! Be careful not to leave it in the flame so long that you stop seeing the color and the splint is actually starting to burn! 5. Immerse the wooden splints in the beaker of RINSE water to fully distinguish it, after the lab is complete you may dispose of all the wooden splints into the regular trash bin. 6. Be sure to record the color of the flame as well as a brief description of its intensity in the data table.

7. Repeat steps 4-6 for the remaining metal salt samples.

8. You are not completely done yet. Obtain two unknown samples from your instructor and repeat steps 4 – 6 with both of these unknowns. Based on your collected data from the other metal salts, identify the metal ion present in each of the unknown samples. Record your answer in the spaces below the data table.

Data Table:

Metal found Flame Color and Intensity in the salt Lithium

Barium

Strontium

Calcium

Copper

Sodium

Potassium

Unknown #1

Unknown #2

Unknown #1 is ______Unknown #2 is ______