Ion Flame Test Inquiry - LABORATORY REPORT
NAME:
PURPOSE:
Focused Idea to Test / Testable Question / Hypothesis
To determine which ion of a compound is responsible for flame color in a flame test.
PRE-LAB NOTES and RESEARCH:
Pre-lab questions and any research or background information referring to the content of the lab.
1. What is an ion?
2. Give an example of a cation and anion.
3. Give an example of an ionic compound.
4. What is a flame test?
MATERIALS:
What materials and equipment were used in this lab?
0.1 M Solutions of:
Strontium Iodide
Potassium Iodide
Unknown and Control
Calcium Chloride
Wooden Splints
Sodium Chloride
Bunsen Burner
Copper Chloride
Sodium Iodide
MgCl2 – Magnesium Chloride
PROCEDURES:
What steps were taken to complete this investigation?
1.
PUT ON YOUR GOGGLES AND KEEP THEM ON!!!
2.
Hold a wooden splint with tongs in the flame.
3.
Watch the flame color and observe any changes from the control.
4.
Repeat for all compounds at your station.
OBSERVATIONS AND DATA:
What did you observe during the lab? What data did you collect? (may include data tables)
Compound
Compound
Formula
Control ??
Positive
Ion
None
NaCl
Negative
Ion
None
Flame
What ion
test color causes color?
None
Cl-1
Calcium
Chloride
Strontium
Iodide
NaI
CuCl2
Magnesium
Chloride
KI
Unknown 1
?
RESULTS / NARRATIVE OF FINDINGS:
Include any calculations such as averages, percent change, percent error and any graphs of data.
What did you observe during the flame tests?
DISCUSSION / INTERPRETATION OF RESULTS:
What do your results mean? How do they compare to your hypothesis? Answer any discussion or post-lab questions
here.
A.
Why is it important to test the flame color of the control without any compounds dissolved in it?
B.
To what group(s) on the periodic table do the positive ions (cations) belong? negative ions (anions)?Are they
metals or non-metals? Why do you think these ions form compounds?
C.
Do the cations or anions cause the change in flame color? Explain why based on your observations.
D.
Why do ions have these characteristic flame colors?(hint: use information from the pre-lab, think electrons!)
E.
Place the elements in order of the amount of increasing energy emitted during the flame test. (use your
electromagnetic spectrum!)
F.
What can flame tests be used for?
G.
If milk that’s boiling spills over into the flame and burns, what color might the flame be? How do you know
that?
H.
If metallic salts produce different colors of light when burned, what is way that this is used in the world?
IMPLICATIONS FOR FUTURE STUDY:
What is something that you could research after this lab? What is another lab that could be an extension of this one?
RELEVANCE:
How does this lab relate to and help you understand the content from class?
Challenge questions: (EXTRA CREDIT)
A. Potassium gluconate (formula = K+C6H11O7-) produces a light purple flame. Copper
(II) sulfate (formula = Cu2+SO4-2) produces a green flame. What flame color would
you expect for copper (II) gluconate (formula = Cu2+[C6H11O7-]2)? Explain.
B.
How could you tell the following three white artificial sweetener powders apart using
the flame test? You have:
1. Equal (C14H18N2O5, a non-ionic compound)
2. Ace-K (K+C3H4NO4S-)
3. Sweet ‘N Low (Ca2+[C7H4NO3S-]2).
C.
Boric acid is a molecular, non-ionic compound. Based on its flame test there is a color
observed, but is this due to positive ions or negative ions? Why?