North Smithfield High School
TOC #
_______
LAB: Flame Test
Name: __________________________________
Period: ____
Date: ___/___/___
BACKGROUND: Working as an analytical chemist at CheMystery Lab, Inc., your research group recently
received a letter from a local family requesting the lab’s assistance (see letter below).
9 Roggler Farm Drive
Woonsocket, RI 02895
Christopher Tucker, Director of Analysis
CheMystery Labs, Inc.
2600 Mendon Road
Cumberland, RI 02864
Dear Mr Tucker:
Our daughter recently found some abandoned, rusted barrels of chemicals while playing in a vacant lot behind our home. The barrels have begun to leak a
colored liquid that flows through our property before emptying into a local sewer. Earlier work done by a city lab indicates that the chemicals contain
dissolved metal compounds.
Because many metal compounds are often soluble in water and therefore easily absorbed into the body, we would like to have these metals identified by an
independent laboratory. Additionally, as many of these metals, such as lead, have been determined to be hazardous to your health, we are quite concerned for
our family’s safety and may decide to take further action against the property owners.
Thank you in advance for your help.
Sincerely,
Julius & Annette Benetti
It is imperative that your research into and analysis of this problem be both very accurate and efficient because
this situation directly affects the health and well-being of the whole community. And although we do not
have any capital expenditure funds for elaborate equipment purchases, we should be able to solve this
problem with the careful qualitative technique known as a flame test.
A flame test is a procedure used to test qualitatively for the presence of certain metals in chemical compounds.
When the compound to be studied is excited by heating it in a flame, the metal ions will begin to emit light.
Certain metal ions will turn the flame very distinctive colors; these colors in turn can help identify the presence of
a particular metal in a compound. Based on the emission spectrum of the element, the compound will turn the
flame a characteristic color. This technique of using certain chemical compounds to color flames is widely used
in pyrotechnics to produce the range of colors seen in a firework display.
OBJECTIVE: Observe the characteristic colors produced by certain metallic ions when vaporized in a flame
and then identify an unknown metallic ion by means of its flame test so as to inform the Benetti’s of the identity
of the chemicals discovered by their daughter in a local vacant lot.
To begin this investigation, your lab journals must be set-up appropriately so that the findings you produce are
able to be clearly communicated to the Benetti’s. (NOTE: This information will ultimately be used for the OnDemand Writing Task of this unit). The following requirements must be included in your lab journal for this
lab:
Focus Question, Planning (Independent/Dependent Variables & Operational Procedure Summary),
Pre-Lab Q’s, Data & Results, Analysis, and Claims & Evidence
BE SURE TO READ THROUGH THE ENTIRE LAB PRIOR TO SETTING UP YOUR JOURNAL.
FOCUS QUESTION: Propose a focus question that provides a link to this research project scenario, cannot be
answered with a simple “yes” or “no” response, and is investigable.
PLANNING: Identify the Dependent and Independent Variables in this investigation to determine which variable
will be changed and which will be kept constant and what will be observed or measured. Then describe the
sequence of events and the materials that will be used to conduct the investigation.
MATERIALS:
Set of solutions: Barium Chloride (BaCl2), Calcium Chloride (CaCl2), Copper (II) Chloride (CuCl2), Lithium
Chloride, (LiCl), Potassium Chloride, (KCl), Sodium Chloride, (NaCl), Strontium Chloride, (SrCl2), and
Unknown
Bunsen Burner
Striker
Q-tips
SAFETY:
1. GOGGLES MUST BE WORN AT ALL TIMES. Removal of goggles will result in removal from
the lab.
2. Long hair must be tied back. Loose clothing and dangling jewelry must be removed.
3. Use caution when working with flames. NO HORSEPLAY.
NON-COMPLIANCE WITH ANY OF THE ABOVE WILL RESULT IN REMOVAL FROM LAB
PROCEDURE:
1. Light the Bunsen Burner following your instructor’s directions and adjust it so that it is a hot blue flame.
2. Using a clean Q-tip, dip it into one of the solutions until it is saturated and then hold the Q-tip in the hottest
part of the burner flame. Observe the color of the flame. Try not to catch the Q-tip on fire, because if you do,
you can’t reuse it to double check the color of the flame test. Carefully record your observations in the data
table. Be accurate here – your description of the color must be accurate enough to distinguish this metal ion
from the other ions tested.
3. Using a different clean/unused Q-tip for each of the other solutions, check the color of their flame tests.
Record your observations for each solution.
4. When you have tested all the unknown solutions and can distinguish the color of each metal ion, obtain an
unknown solution and determine which metal ions are present by performing a flame test and comparing this
data to your previous data.
5. At the end of the lab, turn off the Bunsen burner and clean up your area as directed by your instructor.
PRE-LAB QUESTIONS:
1. Below is a circle graph depicting the colors in the visible spectrum. Transfer the information presented
visually into a data table in your lab journal (such as the one shown below) indicating the range of
wavelengths for each color.
Color
Wavelength range (nm)
2. Look up the safety hazards for each of the chemicals used in this lab activity and record this information into
a data table in your lab journal (such as the one shown below).
Chemical name
Hazard
3. What precautions (3-5) are being taken in this activity to limit the risks associated with using these
chemicals? Think of at least 2 that are additional to the list in the lab.
4. After reading through these directions, label the parts of the lab burner using the following word bank. Cut
out and paste these directions and the diagram for how use a Bunsen burner into your lab journal.
burner barrel (collar)
gas inlet
air vents
base
gas wheel
5. Copy a data table into your journal (such as the one shown below) to collect Data & Results for the following
chemicals: Barium Chloride (BaCl2), Calcium Chloride (CaCl2), Copper (II) Chloride (CuCl2), Lithium Chloride,
(LiCl), Potassium Chloride, (KCl), Sodium Chloride, (NaCl), Strontium Chloride, (SrCl2), and Unknown.
DATA & RESULTS:
Compound
Color
Wavelength Range (nm)
Barium Chloride, BaCl2
Calcium Chloride, CaCl2
ANALYSIS:
1.
Explain how the colors observed in the flame tests are produced. HINT: You should be referencing the “4 step
process of light emission) to answer this question!
2. Does the anion in each of the compounds affect the color observed in a flame test (e.g., sodium chloride,
“chloride” is the anion)? How do you know this based upon your observations?
3. Explain why we did not see distinct lines (like an emission spectrum) when the solutions were burned.
4. The energy of the emitted photon determines the color of light seen in the flame. Which metal ion had the
most energy? Least energy? Explain.
5.
State at least THREE problems that may be involved when using flame test for identification purposes.
6. A glass rod was heated in a burner flame and gave off a bright yellow flame. What metal ion is present in the
glass rod? Explain.
7. Colorful light emissions are applicable to everyday life. Where else have you observed such emission (besides in
the “Line Emission Spectrum Lab”? Are these emission applications related? Explain.
CLAIMS & EVIDENCE:
[PS1 (9-11)–1a] What is the identity of the unknown(s)? Use data to support your claim to the unknown identity and
also to support why ALL of the other substances are NOT the unknown. This will require that you make SEVEN
separate claims and evidence statements (1 to identify the unknown / 6 to identify why the other substances CANNOT
be the unknown.)
Grading Rubric for LAB: Flame Test
Focus
Question
Pre-lab
questions/
lab safety
(x2)
Planning
Data &
Results
Score Point 4
The question provides a clear and
comprehensive link to a possible
engaging scenario, cannot be
answered with a simple “yes” or
“no” response, and is easily
investigable.
Student completes all prelab
questions acurately and completely
demonstrating a readiness to safely
perform the lab activity
The general plan clearly and
concisely determines which
variable will be changed and
which will be kept constant and
what will be observed or
measured.
The operational plan clearly and
concisely describes the sequence
of events and the materials that
will be used to conduct the
investigation.
Data charts, tables, graphs, and
labeled diagrams and illustrations
demonstrate full command of
data organization. Data
organization is clear.
Analysis
(x3)
Student accurately answers all
questions using data/theory as
support.
Claims &
Evidence
(x2)
Claims are clearly and concisely
linked to the data collected or
observed and relevant evidence
justification is provided.
Score Point 3
The question provides a link to a
possible engaging scenario,
cannot be answered with a simple
“yes” or “no” response, and is
investigable.
Score Point 2
The question provides a basic link
to a possible engaging scenario,
cannot be answered with a simple
“yes” or “no” response, and is
somewhat investigable.
Score Point 1
The question provides a limited
link to a possible engaging
scenario, may be answered with a
simple “yes” or “no” response,
and is minimally investigable.
Student completes all prelab
questions acurately and completely
demonstrating a readiness to safely
perform the lab activity. Minor
errors do not exclude student from
participation in lab
The general plan determines
which variable will be changed
and which will be kept constant
and what will be observed or
measured.
Student completes some prelab
questions acurately and completely
demonstrating that with teacher
assistance they will be ready to
safely perform the lab activity
Student does not complete prelab
questions acurately and completely
and does not demonstrate a
readiness to safely perform the
lab activity
The general plan somewhat
determines which variable will be
changed and which will be kept
constant and what will be
observed or measured.
The general plan incorrectly
determines which variable will be
changed and which will be kept
constant and what will be
observed or measured.
The operational plan describes the
sequence of events and the
materials that will be used to
conduct the investigation.
The operational plan somewhat
describes the sequence of events
and the materials that will be used
to conduct the investigation.
The operational plan incorrectly
describes the sequence of events
and the materials that will be used
to conduct the investigation.
Data charts, tables, graphs, and
labeled diagrams and illustrations
demonstrate command of data
organization. There may be minor
errors but data organization is
mostly clear.
Student answers all questions
using data/theory as support with
minor errors that do not detract
from the meaning.
Claims are linked to the data
collected or observed and
evidence justification is provided.
Data charts, tables, graphs, and
labeled diagrams and illustrations
demonstrate some command of
data organization. There may be
errors that somewhat impede data
organization.
Student answers all questions with
major errors that detract from the
meaning. Data/theory may be
missing/inaccurate.
Claims are somewhat linked to
the data collected or observed and
basic evidence justification is
provided.
Data charts, tables, graphs, and
labeled diagrams and illustrations
demonstrate limited command of
data organization. There may be
minor errors often impede data
organization.
Questions are not answered.
Claims are minimally linked to
the data collected or observed and
limited evidence justification is
provided.
SCORE: ______
*This grade will account for 50% of your Unit Test grade. The remaining 50% will be accounted for through your
On-Demand Writing Task.
CUT OUT THE DIRECTIONS & DIAGRAM OF THE BUNSEN
BURNER AND GLUE INTO JOURNAL.
Using the Bunsen Burner
SAFETY PRECAUTIONS

Goggles are required at all times.

Tie hair back.

Do NOT lean over the flame.

Restrain baggy clothing.

Do NOT pass materials over the flame.

Remove flammable items from lab bench.

Do not leave your burner unattended.
Inspecting the Burner
1. Find and examine the burner at your workstation. Familiarize yourself with all parts. Inspect the
rubber hose, looking for cracks and a good attachment to the burner itself through the Gas Inlet.
Be sure that the Base of the burner is flat on the lab table surface.
Gas/Air Control
2. The Gas Wheel is the knob beneath the burner and controls how much gas enters your burner.
This gas wheel is OFF when screwed into the base (counterclockwise) as far as it will go without
forcing. Turn your GW to the ‘off’ position. No gas can enter your burner now.
3. The flow of air (not gas) into the burner is controlled by the position of the Burner Barrel
(Collar). By rotating COUNTER CLOCKWISE, more air is allowed in, making a larger flame.
Turn the barrel OFF by rotating CLOCKWISE; again do not force the barrel.
4. Locate the gas valve at your lab station. It is OFF when perpendicular to the burner hose. If it is
PARALLEL, then you have gas flowing. DO NOT TURN ON UNTIL YOU ARE READY! We
will either have this control ‘Full on’ or ‘Full off’.
Lighting Burner
5. Open the Air Vents slightly (3 or 4 full turns) by turning the burner barrel counterclockwise. You
should be able to see that the air vents are open.
6. Turn on the gas valve to full on. Turn the gas wheel two turns until you can hear the flow of gas
coming through the burner barrel.
7. Use the striker above the burner collar to light the Bunsen Burner. If you do not get a flame, turn
off the gas valve and let your instructor know.
8. Adjust the air flow to the burner by turning the burner barrel counterclockwise. The flame should
be blue by now and no noise should be heard; this is optimal.
Extinguish Burner
9. Turn gas off at the gas valve. Close the gas wheel. Do not close the burner barrel (since it may be
hot to touch)