Flame Test Lab
You will be conducting flame tests to see the different colors emitted by
substances and then use what you have observed to identify an
unknown substance.
SAFETY: You must wear googles. Hair should be tied back and loose
articles of clothing should be restrained. Any objects that have been
burned should be doused with water before throwing into the trash.
Procedure:
1. Obtain a beaker with distilled water.
2. Obtain cotton swabs.
3. Take one of the beakers of labeled substances to your lab station.
4. To light your burner. Hook the rubber tubing to the gas and the
burner. Have your flint ready (or match lit) and turn on the gas. If
using a match, slowly raise the match from the bottom of the
burner to the top. Adjust the oxygen ring until you have a blue
flame.
5. Dip the cotton swab in the water, then into the substance.
6. Hold the cotton swab in the flame and note the color.
7. Put the cotton swab in water then dispose in the trash.
8. Repeat with the other substances including the unknown.
Name
Formula
of Metal
Chloride
Color of
Flame
Approximate
Wavelength
Lithium
chloride
;Sodium
chloride
Barium
chloride
Potassium
Chloride
Strontium
chloride
Copper
chloride
Unknown
Representative Wavelength
Color
Wavelength
Region
(nm)
(nm)
Violet
420
400 - 440
Blue
455
440 - 470
Blue480
470 - 490
green
Green
525
490 - 560
Yellow
565
560 - 570
-green
Yellow
580
570 - 585
Orang
620
585 - 630
e
Red
660
630 - 700
Analysis Questions
1. Most salts contain a metal and a non-metal. Look at the
compounds we tested and determine whether it is the metal or
the non-metal that is responsible for the color produced in the
flame test for that salt. How can you be sure your answer is
correct?
2. What colors did the unknown produce in the flame? What is the
unknown?
3. Could flame tests be useful in determining identities of metals in a
mixture of two or more salts? If so, what problems might arise? If
not, why not? Explain your answer.
4. How sensitive is the flame test? Could it be used to accurately
identify metal ions? What difficulty could there be when
identifying ions by the flame test?
5. Fireworks come in a variety of colors. Explain how the fireworks
manufacturers could get these colors.
Hints for your lab report
Introduction: You might have to look online to get some information about this
topic. Think about your procedure, what problem are you trying to solve and
how are you trying to solve it? Think about what background information
both you and your reader would have to know to understand what you will
base your conclusions on.
Conclusion: Since you haven’t learned much about this topic, it is really important
that you talk about what this experiment makes you curious about and what
you think you might need to know to get accurate results.