TEN SOLUTION PROBLEM
HONORS CHEMISTRY PROJECT
THIRD QUARTER
2001
Purpose:
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To become familiar with chemical tests used to identify the presence or absence of a
particular cation/anion in a solution.
To use these tests to identify the cation and anion present in each of ten solutions.
To become familiar with the chemistry of common cations and anions.
To practice and develop skills involved in conducting chemical investigations and in the use
of specific equipment used in these investigations.
To practice and develop the skill of keeping an accurate experimental record.
To become familiar with the practice of writing net-ionic equations for chemical reactions that
occur in solution.
To practice and develop the skill of consulting technical literature.
Background:
Ten solutions, each containing one cation and one anion from the list below, are to be tested to
determine the cation and anion present in each. The solutions are 0.20 M. It is extremely important that
you do not contaminate these solutions. Only withdraw solution, using a clean, disposable pipet. Common
chemical reagents will be available for your use, i.e. HCl, AgNO3, etc. Other reagents can be made
available if they are in stock and sufficient time given for their preparation. Your tests may include, but not
limited to, mixing combinations of the ten solutions. The initial appearance of each solution might be
helpful in your analysis.
You are to work in pairs. Groups are not to interact with other groups on this project. You are
in violation of the Honor Code if you consult with another group, provide information to another group, or
receive information from another group. Each group will be assigned a basket that will contain two well
plates and several test tubes. You are to keep all of your materials together in a designated place in the lab.
Your experimental work is to be conducted on your own time. You may use your study hall/free period to
come in and work, or before and after school. Mrs. Allen or Ms. Jamison must be present in the lab room
when you conduct experimental work. Some class time will be set aside to allow you and your partner to
conduct experimental work. A detailed record of your work is to be kept in a journal, which will be given
to you later this week. The entries are to be made directly in your journal, in ink, including the date, what
you did, and a detailed description of your observations. You are expected to follow all prudent safety,
disposal, and clean-up practices and keep up with your basket of materials. If the lab begins to be messy,
ALL LAB GOUPS WILL HAVE POINTS DEDUCTED FROM THEIR GRADES. You will be penalized
for failure to do so.
The analysis of the results should include the identity of the ions present in each solution
supported by experimental evidence and based on the information derived from the literature. Balanced
net-ionic equations for the reactions involved in the identification are to be included.
Example: Solution X contains the carbonate ion, CO32-. This is based on the fact that carbonates
will release carbon dioxide gas when acidified; if the gas is passed through limewater [Ca(OH) 2] and a
white precipitate forms, the gas is carbon dioxide.
CO32- + 2 H1+  H2O + CO2(g)
CO2(g) + Ca2+ + 2 OH1-  CaCO3(s) + H2O
We acidified solution X by adding hydrochloric acid. The evolution of a gas was observed. We repeated
the acidification in a test tube connected with a gas delivery tube. The gas delivery tube was placed in a
small beaker of limewater, and the gas was allowed to bubble through it. The limewater clouded up,
verifying the presence of carbon dioxide.
The due date for this project is Tuesday, February 20, 2001. A penalty of 10% per day late
will be assessed. The project is equivalent to one test grade and one lab grade. DO NOT WAIT TO THE
LAST MINUTE. BEGIN EARLY AND DO A LITTLE EACH WEEK!
Cations
Ammonium
Barium
Calcium
Cobalt(II)
Copper(II)
Cations
Iron(II)
Lead(II)
Nickel(II)
Potassium
Sodium
Anions
Acetate
Bromide
Carbonate
Chloride
Hydroxide
Anions
Nitrate
Phosphate
Sulfate
Note: Two of the possible anions occur in more than one solution.
Each group will submit one report, which includes the following:
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Journal (In ink, showing dates, what you did, and your observations.)
Analysis (Should be typed.)
Bibliography
Evaluations of partner’s contributions to project. (Place in sealed envelope.)
Basket returned with clean materials
Grading will consist of the following:
20% for accurately determining the identity of each ion
60% for citing experimental evidence, support/reasoning for each ion. Net ionic equations where
appropriate are also required. Note: if proper support if given for an incorrect ion, no
penalty will be assessed.
15% for Journal evaluation: does it support your conclusions? Is it dated and signed? Is it
thorough?
5% for Bibliography
10% based on peer evaluation responses
(10% deduction for failure to return clean basket with materials)