Flame Test Lab.pdf

Mrs. E. Dharmai
SCH3U1 Flame Test Lab
Each element has a unique line spectrum. We can use these fingerprints to determine metals
present in unknown metallic compounds. Flame tests are used to do so. When an unknown
sample is heated, the resulting flame colour can be compared to a chart of known flame
colours.
Flame Test: a diagnostic technique in which a metallic compound is placed in a flame and the
colour produced is used to identify the metal in the compound.
This lab will be conducted in 2 parts:
a) Creating a flame test key from known metallic compounds
b) Identifying an unknown metal in a compound by using the flame test key
Materials:
Goggles
Nichrome test wire
Test tubes
Test‐tube rack
Bunsen burner
Hydrochloric acid,
dilute
Samples of the
following solids:
Sodium chloride
Barium chloride
Calcium chloride
Strontium chloride
Lithium chloride
Potassium chloride
Copper (II) chloride
Various unknown
metallic compounds
Procedure:
Part A: Creating a Flame Test Key
1. Obtain your solid samples and 5 mL of hydrochloric acid solution.
2. Light the Bunsen burner and adjust it until you get a blue flame.
3. Clean the nichrome wire by dipping it into the hydrochloric acid and then holding the
wire in the flame until the wire adds no colour to the flame.
4. Pick up a small amount of solid sodium nitrate with the wire loop. Hold the end of the
wire in the flame. Record your observations.
5. Clean the wire as in step 3.
6. Repeat steps 4 and 5 with the remaining known samples to complete your flame test
key.
Part B: Identifying Metals in Unknown Metallic Compounds
1. Obtain samples of the unknown metallic compounds.
2. Test each sample using the steps 3 and 4 from above. Record your observations and
determine the metal in the unknown samples.

Mrs. E. Dharmai
Discussion
1. Sodium chloride was tested in this lab and produced a specific flame test colour.
a) Describe the colour.
b) Predict the flame test colour if you had tested sodium nitrate. Explain.
2. Why do the compounds have to be heated in the flame first before the coloured light is
emitted?
3. This lab tested several salt compounds that contained a metal and a non‐metal. Is it the
metal or the non‐metal that was responsible for the colour that was produced in the
flame test? Explain.
4. Fireworks come in a variety of beautiful colours. What can you conclude about the
composition of a firework if it displays a red colour upon lighting?