THE IDENTIFICATION LAB (Lab Guidelines 1 2 3 4

the identification lab (lab guidelines: 1, 2, 3, 4, 5&6 [attach handout], 7, 12) purpose: to identify an unknown metallic halide solution

THE IDENTIFICATION LAB
(Lab Guidelines: 1, 2, 3, 4, 5&6 [attach handout], 7, 12)
Purpose: To identify an unknown metallic halide solution using data
from known metallic halide solutions.
Introductory Material: Metallic halides, cations, anions, basic
formula writing and naming, precipitate formation.
Materials: Known metallic halide solutions (0.10 M), silver nitrate
(0.10 M), sodium thiosulfate (0.50 M), ammonia (6.0 M), spot plate,
Bunsen burner, nichrome wire, concentrated HCl
Procedure:
DAY 1
Plan a procedure to test whether or not the known metallic halides
form precipitates when mixed with silver nitrate. Use 3 drops of each
solution.
If a precipitate does form, add ammonia and note whether or not the
precipitate dissipates. “Jiggle” the spot plate to assure complete
stirring has taken place.
If ammonia causes no change, add sodium thiosulfate, and note whether
or not the precipitate dissipates.
Compare your results to other groups to make sure there is consensus
in the class!
Next, you will need to perform all of the above steps with your
unknown metallic halide solutions. Remember to note the unknown letter
in your data.
Something to think about: Look at your data and determine whether the
above tests tell you more about the metal ion present or about the
halide ion that is present.
DAY 2
Note the proper procedure for conducting a flame test on the halides
of sodium, lithium, potassium, copper, barium, and calcium.
Now perform a flame test on your unknown metallic halide solutions.
Does this test tell you more about the metal ion present or about the
halide ion that is present in your unknown?
Data: Create an appropriate data table to chart precipitate formation,
dissipation, and flame test results.
Conclusion:
Discuss how you accomplished the purposes of the lab. Also include the
following!
1. Identify your unknown – the cation and the anion, and the formula
of the compound.
At the beginning of your conclusion section, please include a box with
the unknown letters,
cation present, anion present and formula of the compound.
2. Describe in detail how you know what it is. Refer to procedure and
data.
3. List at least three new chemical concepts you learned in this lab.