Jack M. Barrack Hebrew Academy
2013 – 2014, Tri 1
Honors Chemistry
Dr. Darin Katz
Lab Experiment # 3- Flame Tests
The objectives of this lab are:
(1) to experiment with flame tests on different salts;
(2) to predict the identity of an unknown metal ion;
(3) to understand how atomic absorption and emission relate to flame tests.
General Instructions:
1. Please read the attached lab sheets so that you are familiar with the procedure(s)
and what type of data you will collect. I have made many modifications to the procedure
so try your best to get a jist of what you will be doing.
2. Please answer the pre-lab questions on the next page after reading the lab. Your
completed pre-lab questions are due at the beginning of your lab period. They will
count towards your grade on this lab.
3. Important safety precautions: wear goggles and apron; flames will be on so tie
your hair back.
Instructions for Lab Report:
1. This WILL BE your formal lab report for Trimester 2. See Guidelines for Formal
Lab Reports.
2. Your lab report must contain the following:
a. Heading
b. Title
c. Introduction
(i) Paragraph 1 - objectives
(ii) Paragraph 2 – science concepts and vocab terms
d. Materials and Methods
e. Data (this is where your data table will go – remember to number and title it!)
f. Conclusion and Analysis :
(i) Paragraph 1- sources of real error
(ii) Answers to post-lab questions – typed and pasted in your lab book.
3. Your lab reports are due on:
Jack M. Barrack Hebrew Academy
2013 – 2014, Tri 1
Honors Chemistry
Dr. Darin Katz
Lab Experiment #3- Flame Tests
Pre-lab Questions/Exercises
Name
Please answer the following questions after reading your lab sheets. These completed
questions are due at the beginning of your lab period.
1. What safety equipment AND precautions are important for this experiment?
2. Of the metals that you will be testing (found on next page in Materials), list the group from
which they come:
Group 1 Metals:
Group 2 Metals:
Transition Metals (Groups 3 – 12):
3. List two common situations in which you would encounter metal ions giving a colored flame.
You may use the internet; cite your sources.
4. How exactly (be specific!) will you determine the identity of your unknown solution?
5. Which of the 6 divisions of chemistry would this type of experiment fall into?
6. Now create a data table to be used during the lab. The table should show the chemical name
of each compound you will test and a column for the color produced. Make sure to also include
a space for the unknown solution you will test. You will show the table to DDK before starting
the lab.
Lab Experiment #3- Flame Tests
Background Information
When atoms or ions in the ground state are heated to high temperatures, some
electrons may absorb enough energy to allow them to “jump” to higher energy levels.
These excited state electrons are unstable and they will “fall” back to their normal
positions of lower energy. As the electrons return to the ground state, the energy that
was absorbed is emitted in the form of electromagnetic energy. Some of this energy
may be in the form of visible light which means we can see it!
Lab Experiment #3- Flame Tests
MaterialsWooden splints
Bunsen burner
Spark lighter
Aqueous solutions of the following: (aqueous means the salts are dissolved in water)
Sodium nitrate
Lithium nitrate
Potassium nitrate
Calcium nitrate
Strontium nitrate
Calcium nitrate
Barium nitrate
Copper nitrate
Sodium nitrate/Potassium nitrate mixture
Sodium chloride
Solid Sodium chloride crystals
Unknown aqueous solution of a metallic ion
Procedure1) Take a wooden splint from each aqueous solution and place it in the Bunsen
burner flame. Carefully record the color that the solution imparts on the flame.
Record your data in the Data Table.
2) Place a few crystals of solid sodium chloride on a wet wooden splint. Hold the
splint in the flame and record the color that the crystals impart on the flame.
Record your data in the Data Table.
3) Obtain an unknown from DDK. Test it in the flame as you did with the known
substances. Record your data in the Data Table and determine the identity of
your unknown.
Post-lab Questions1) Is flame coloration a test for the metallic ion or the nitrate ion? Justify your
answer.
2) Why do solid sodium chloride crystals and the aqueous solutions of sodium
chloride and sodium nitrate all impact the same color to the flame?
3) Compare the results for the sodium nitrate/potassium nitrate mixture with the
sodium nitrate and potassium nitrate solutions when each was alone. Provide a
possible explanation for your results.
4) Several of the flame tests were shades of red. What could be done in the
laboratory other than repeating the flame test to correctly identify one of these
ions?
5) During a flood, the labels from three bottles of chemicals floated away. The
unlabeled bottles of white solids were known to contain the following: strontium
nitrate, potassium sulfate, and ammonium carbonate. Using what you have
learned from this lab exercise, explain how these three bottles could be easily
re-labeled.
6) The chemistry behind this lab experiment can be applied to fireworks. Using
internet sources or your textbook, research why fireworks produce different
colors when ignited. Write a one or two-paragraph answer to this question. Your
answer should include terms that we have been using in class (i.e., ground state,
excited state, others). Cite your sources.