Transcript LS10

Chemistry XXI
Lab Session 10
How can we use chemical
reactions to identify substances?
(Two-Week Experiment)
Your Challenge
Imagine that you work for a mining company that is
about to buy a new mine in Southern Arizona.
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You have been asked to identify the metals present
in samples of the ore extracted from the mine.
What different metals are present in the ore?
The Sample
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Your group will be
provided with a ore
sample from the
Rosemont Ranch
area of the Coronado
National Forrest
(pictured to the
right).
You assignment is to determine what metals
are present in the ore.
Your Analysis Scheme
Discuss with your group your proposed
analysis scheme. Make sure every
separation and identification steps are
sound and clear.
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Ba2+ , Al3+ , Ni2+, Cu2+
Solution
Precipitate
The
scheme
needs
to
be
tested.
2+
3+
Ni , Al
Ba2+, Cu2+
C2O42The ore needs to be put into solution. Re-dissolve
1 M HNO3
A method for re-dissolving the precipitates needs
Separate?
Separate?
to be identified.
Skill Building Tests
Apply your analysis scheme to a mixture of
known cations. Make the necessary
modifications to separate and identify the
metal cations in the mixture.
Available resources:
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 Anion and test solutions.
 Cation solutions prepared by your
fellow students.
 A mixed solution of all cations
prepared by the preproom.
 1 M HNO3
 Test tubes and other glassware.
You have 60
minutes
Results and Reflections
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Share with your classmates what worked
and what didn’t work in your proposed
analysis scheme.
Modify your analysis
scheme based on all
of the information
and data that you
have gathered.
Ore Analysis
Discuss how do you propose to
analyze the ore.
Develop a plan that addresses the following
points:
 How to dissolve the minerals in the ore;
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 How to separate undesired materials;
 How to separate and identify the different
metal cations in the ore.
Your Real Challenge
Analyze the ore sample.
Available resources:
 Anion and test solutions;
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 Cation solutions prepared
by your fellow students;
 1 M HNO3;
 An ore sample.
 Test tubes and other glassware.
You have 90
minutes
Claims and Evidence
Based on the results of your experiments,
present your major claims and the
evidence that you have to support the
answer to the challenge.
 Are their claims clear?
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 Is the evidence reliable?
 Is the evidence appropriate to support the
claims?
 How do you explain the results?
Final Reflections
 What did you learn from doing your
experiment?
 How would you improve what you did?
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 How have your ideas changed as a result
of this lab?
 What do you not completely understand?
 What new questions do you have?
Your Report
 Beginning questions (2 p):
What questions guided your explorations?
 Safety Considerations (2 p):
What did you do to stay safe in the lab?
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 Procedures and Tests (2 p):
What experiments did you do to answer your
questions?
 Data, calculations, and representations (6 p):
What observations did you make?
What data did you collect?
What calculations and representations helped
you make sense of the data?
Your Report
 Claims (2 p):
What can you claim to answer your questions?
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 Evidence and Analysis (6 p):
How did you interpret your results to support
your claims?
 Reflections and additional questions (10 p):
What did you learn?
What do you not completely understand?
How have your ideas changed as a result
of this lab?
What new questions do you have?
How would you improve what you did?
Next Week
Next week we will be testing a new
experiment in all of the Chemistry XXI labs.
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Necessary information will be posted in D2L.
Remember to complete the post-lab
quiz for this two-week experiment and
complete you lab report.