The Flame Test Student Worksheet
- Put on lab apron and safety goggles.
- Add 15 drops of each 0.5M solution to a different clean test tube.
- To clean the wire, dip it into the test tube of 1M of HCl and heat
the wire in the hottest part of the flame until no color shows.
- When the platinum wire is clean, dip the wire in the test tube
containing a 0.5M solution and hold it in the hottest part of the
Record your observation of the color of the flame on the data table.
- Repeat the process of cleaning the platinum wire. Now get ready
to test another solution.
- Test all of the solutions and make sure that you record the
color of the flame for each element on the Data Table.
- Check your flame colors to known results.
- Fill one clean test tube with 15 drops of one of the 0.5M
solutions. The teacher keeps track of what element solution is in this
"mystery tube." Repeat the flame test, without telling the students
solution it is. Students must use the information gained from the
first part of the experiment to identify the mystery solution.
- Use the diffraction grating to observe the color of the flame for
following elements: Sodium, Barium, Copper, and Lithium. The students
should be able to see the individual lines making up the light from
the flame. This can be tricky! In order for it to work, the room will
have to be completely dark (in order to block out other light sources)
and the students will have to be close to the flame, holding the
diffraction grating up to their eyes. It may be necessary to rotate
the diffraction grating in order to see the emission lines. Be
- Record the colors of the elements' emission lines in column three
the Data Table.
- Before leaving the laboratory, wash your hands thoroughly with
soap and water.
|Calcium (0.5M CaCl)
|Sodium (0.5M NaCl)
|Barium (0.5M BaCl)
|Lithium (0.5M LiCl)
|Copper (0.5M CuCl)
Discuss the following questions in lab groups.
Remember you are trying to determine what is taking place during
the Flame Test whereby various colors of light are being emitted. One
person in your group will have the responsibility of writing the group
answers down. After discussing these questions in the group, another
person will be responsible for sharing your thoughts with the whole
class. You may refer to background material.
- What particles are found in the chemicals that may be
responsible for the production of colored light?
- Why do different chemicals emit different colors of light?
- Why do you think the chemicals have to be heated in the
flame first before the colored light is emitted?
- Colorful light emissions are applicable to everyday life.
Where else have you observed colorful light emissions. Are
these light emission applications related? Explain.
- What is the characteristic flame color for Sodium, Lithium,
Barium, Copper, Cesium, and Calcium? Explain why.
- When the diffraction grating was used to view the flame,
explain why different colorful emission lines were observed for the
Use the image below to view the spectra of
calcium (top) and sodium
(bottom). Solve for frequency and
energy of the two brightest emission lines for each element. Use the
brightest lines. Show your work and record your answers on the Data