Lab: Flame Tests for Metal Ions
CP
Purpose
To observe the atomic spectra of a variety of metal ions and to identify the ion present
in an unknown solution.
Equipment and materials
• paper towel
• Laboratory Bunsen burner
• Colored drawing pencils
• Goggles
• Wooden splints, soaking in water
• Chemicals: NaCl, KCl, LiCl, CaCl2, SrCl2, CuCl2, and unknown.
Methods
Safety note: Wear goggles!!! And make sure the wooden splints are not burning when you
dispose of them in the trash cab.
1. Get a paper towel and label the paper towel with each of the solution formulas (NaCl, KCl,
LiCl, CaCl2, SrCl2, CuCl2, and unknown)
2. Obtain a wooden splint and dip it into one of the metal chloride solutions.
3. Carefully light laboratory burner and slowly pass the wooden splint back and forth
through the flame. After carefully observing the flame, put the wooden splint back on the
paper towel (if the wooden splint is on fire, just turn on the tap water at your sink and put
out the flame)
4. Record observations. ***give good written descriptions of the colors you see!!!
5. Repeat steps with another salt, until all ions have been tested.
6. Repeat steps with the unknown salt. Determine which ion is present in this solution.
7. Once the laboratory work is complete, throw out all wooden splints, the paper towel, and
used matches, put all other materials back where you got them, and wash hands with soap.
8. Answer questions #1 & 2 below.
Observations and data
Solution
Metal Ion
Present
Written description of color(s)
observed
NaCl (aq)
KCl (aq)
LiCl (aq)
CaCl2 (aq)
SrCl2 (aq)
CuCl2 (aq)
unknown
Calculations and conclusions:
1. Discuss some of the limitations of using flame tests to identify ions present in
solution.
2. Propose at least one possible method for improving the accuracy of results in this
laboratory experiment.