Flame Test: Watch Glass

Purpose:

  1. To observe the different colors emitted by ions in a flame test.

Materials:

  1. Barium Nitrate
  2. Calcium Nitrate
  3. Lithium Nitrate
  4. Potassium Nitrate
  5. Sodium Nitrate
  6. Strontium Nitrate
  7. Copper Sulfate
  8. Matches
  9. Methyl Alcohol
  10. 7 Watch Glasses
  11. Mortar & Pestle

Procedure:

  1. Powder the salts in the mortar, cleaning it out between salts.
  2. Put salt 1 in watchglass 1, salt 2 in watchglass 2, and so on.
  3. Pour 5 mL of methyl alcohol in each watchglass.
  4. Using a match, carefully ignite the alcohol in watchglass1.
  5. After the alcohol level nears the salt, record the color of the flame.
  6. Repeat steps 4 and 5 for all the salts in watchglasses 2-7.

Data and Information

Metal Ion Formula of Salt Color of Flame
Ba+2 Ba(NO3)2 Color:
Ca+2 Ca(NO3)2 Color:
Li+ LiNO3 Color:
K+ KNO3 Color:
Na+ NaNO3 Color:
Sr+2 Sr(NO3)2 Color:
Cu+2 Cu(NO3)2 Color:


Questions:

  1. What kind of colors are emitted by the ions?
  2. Does the alcohol change the color of the flame? Why, or why not?
  3. Can a flame be used to identify a metal ion? Why, or why not?