While putting away the materials from an experiment that was set up by Dr. Burton, it was observed that six of the bottles had lost their labels. By checking the inventory of reagents used in the experiment the names of the six reagents was obtained. When Dr. Burton saw the list, she was able to set up a simple series of fifteen tests that would identify each of the unlabeled bottles. She realized that this was an even more challenging experiment that the one that was originally set up.

Dr. Burton now challenges you to identify these six reagents. What you need is a set of the same six reagents, but with their proper labels in place. You will mix two different reagents together and observe what happens. There are fifteen of these you have to perform. Then you repeat the experiment with the six unlabeled (except to keep track of them you have given each a different letter, so that you don't use the same solution twice in a test. Or repeat a test you have already done)

From the fifteen mixings using the unlabeled bottles and from the results you should be able to determine which unlabeled bottles contain which of the chemical substances ( remember you have given each its own identifying letter ) . Actually to get you started two tables have been prepared , one listing the chemicals and the other listing the assigned letters. The three indicators of a reaction that you will be observing are a) the formation of a solid, b) the formation of a gas, and c) the change in the amount of heat if neither a) nor b) are observed.

Equipment:

At least 15 test tubes, a test tube rack, disposable medicine droppers.

Chemicals:

The six unknown reagents in bottles (lettered A, B, C, D, E, and F), the same reagents, but with their correct labels. 0.10 M aluminum chloride, 0.10 M calcium chloride, 0.20 M sodium carbonate, 0.10 M sodium chloride, 0.20 M sodium hydroxide, and 0.20 M sulfuric acid (listed in alphabetical order)

Procedure

For each of the named compounds you should also write its chemical formula. You are going to need a table of solubility's so that you can tell what solid has been formed in a chemical reaction. One is provided with this experiment, but it contains more substances than you will be handling in this experiment. A table of gases produced in chemical reactions will also be provided, and again it will cover more gases than you will deal with in this experiment.

Mix the fifteen different combinations of the known solutions and record your results in the table provided. (Remember mixing NaCl with CaCl₂ is the same as mixing CaCl₂ with NaCl . ) Now repeat the fifteen different combinations with the unknown solutions and record these in the second table. By comparing the two sets of results you should be able to identify each of the unknown labeled bottles.

Once you have determined which reactions occurred, you should, if possible, write the chemical equation for that reaction. Your instructor will indicate which items are to be turned in so that you receive credit for this experiment.

Formula	AlCl3	CaCl2	Na2CO3	NaCl	NaOH	H2SO4
AlCl3
CaCl2
Na2CO3
NaCl
NaOH
H2SO4

Formula	A	B	C	D	E	F
A
B
C
D
E
F

Table of Solubility’s For water solutions.

1. All nitrate (NO₃ ^1- ) , ammonium (NH₄ ¹⁺ ) , potassium K ¹⁺ , sodium Na ¹⁺ salts are soluble .

2. All chloride Cl ^1- salts are solubleEXCEPT : AgCl , Hg₂Cl₂ , and PbCl₂ .

3. All sulfate (SO₄ ^2- ) salts are soluble EXCEPT : PbSO₄ , SrSO₄ , BaSO₄ .

The following sulfates are slightly soluble: Ag₂SO₄ , CaSO₄ , Hg₂SO₄ .

4. All carbonate (CO₃ ^2-) , and phosphate (PO₄ ^3-) salts are insoluble

EXCEPT : NH₄ ¹⁺ , Na ¹⁺ , and K ¹⁺ salts .

5. All sulfide S ^2- ,and hydroxide (OH ^1- ) salts (bases) are insoluble

EXCEPT : NH₄ ¹⁺ , Na ¹⁺ , K ¹⁺ , Ba ²⁺ , Sr ²⁺ , and Ca ²⁺ salts .