I.
Objectives: The objectives are to use the flame
test to determine the identity of the cation in an unknown solution based on
its characteristic color flame.
II.
Materials & Procedures:
A. Materials:
Bunsen burner, 7 small test tubes, test tube rack, 7 small cotton swabs, NaCl,
CaCl2, LiCl2, KCl, BaCl2, SrCl2,
CuCl2
B. Procedures:
1.Draw
the data table including compound cation and color.
2.Label
the test tubes and add 1ml of chemicals to the test tubes.
3.Dip
one end of the swab in the chemical and hold it in the flame. Record the color.
Set swab aside.
4.Repeat
step 3 for each chemical using a different swab for each one.
C. Safety:
III.
Analysis:
A. Data
Table
|
Compound Formula
|
Cation
|
Color
|
|
NaCl
|
|
|
|
CaCl2
|
|
|
|
LiCl2
|
|
|
|
KCl
|
|
|
|
BaCl2
|
|
|
|
SrCl2
|
|
|
|
CuCl2
|
|
|
B. Questions:
1.Each
salt solution produces a unique color. Would you expect this based on the
modern view of the atom? Explain.
2.Some
commercially available fireplace logs burn with a red and/or green flame. On
the basis of your data, what elements could be responsible for these colored
flames?
3.Aerial
fireworks contain gunpowder and chemicals that produce colors. What element
would you include to produce crimson red? Yellow?
IV.
Conclusion:
