Water Testing Lab Report



WATER TESTING LAB

June 25, 2013

Abby, Jilly, Layla

Chemistry

Dr. Forman

Abstract:

   The purpose of the lab was to learn how to test various substances for ions. We tested distilled water, a reference solution, an unknown solution, tap water, and ocean water for calcium, iron, chloride, and sulfate ions. The distilled water was our blank well, in which we were to expect no precipitate. Our reference solutions were used to know what a precipitate would look like. If the substance changed when we added the chemicals then a precipitate would form and we could conclude that the ion was present. If the substance didn't create a precipitate then we would conclude that there were no ions present. This lab tested our teams' carefulness and we had to pay close attention to directions. In addition, we had to be extremely careful to not cross contaminate chemicals as that could cause false results. 

Procedure:

1. Preparation
1. be sure to clean all equipment before and throughout the lab
2. put on gloves and other safety equipment
3. Gather all of the chemicals 
2. Calcium Ion Test



1. Put 20 drops of each of the following into individual wells and label: distilled-water blank, calcium reference, unknown, tap water, and ocean or natural water. 
2. Add three drops of the sodium carbonate test solution to each of the wells. You should see no change in the coloring of the distilled-water well but you should see a reaction in the solution well. If these results are not the case make sure you are doing the procedure correctly. 
3. Stir with the glass rod being careful to wash and dry the rod after each well
4. Record results of the coloration in a table: 
5. We concluded that there was no ion present in the unknown substance
6. Wash the well plate, rod, and pipette with distilled water
3. Iron Ion Test

1. Put 20 drops of each of the following into individual wells and label: distilled-water blank, Iron reference, unknown, tap water, and ocean or natural water. 
2. Add one or two drops of the potassium thiocyanate test solution to each of the wells. You should see no change in the coloring of the distilled-water well but you should see a reaction in the solution well. If these results are not the case make sure you are doing the procedure correctly. 
3. Stir with the glass rod being careful to wash and dry the rod after each well
4. Record results of the coloration in a table: 
5. We concluded that there was no ion present in the unknown substance
6. Wash the well plate, rod, and pipette with distilled water
4. Chloride Ion Test
1. Put 20 drops of each of the following into individual wells and label: distilled-water blank,Chloride reference, unknown, tap water, and ocean or natural water. 
2. Add three drops of the Silver Nitrate test solution to each of the wells. You should see no change in the coloring of the distilled-water well but you should see a reaction in the solution well. If these results are not the case make sure you are doing the procedure correctly. 
3. Stir with the glass rod being careful to wash and dry the rod after each well
4. Record results of the coloration in a table: 
5. We concluded that there was no ion present in the unknown substance but there was in the tap and ocean water
6. Wash the well plate, rod, and pipette with distilled water
5. Sulfate Ion Test
1. Put 20 drops of each of the following into individual wells and label: distilled-water blank, sulfate reference, unknown, tap water, and ocean or natural water. 
2. Add three drops of the barium chloride test solution to each of the wells. You should see no change in the coloring of the distilled-water well but you should see a reaction in the solution well. If these results are not the case make sure you are doing the procedure correctly. 
3. Stir with the glass rod being careful to wash and dry the rod after each well
4. Record results of the coloration in a table: 
5. We concluded that the ion was present in the all of the substances except for the tap and distilled water
6. Wash the well plate, rod, and pipette with distilled water

Results:

1. There was a reference solution to see what an ion being present would look like while a blank is to see what a solution that doesn't create a precipitate looks like. 
2. The possible problems associated with qualitative tests are that there can be differing answers. 
3. The tests cannot completely confirm the absence of an ion because there could be such a small amount of an ion in a liquid that it doesn't change the appearance of the solution.
4. The observations may have changed if we hadn't properly cleaned the rod because we may have contaminated the wells to show false ions present.

Significance/ Results Discussion:

   We confirmed that the unknown solution had sulfate ions present. Our group had a differing conclusion as to if the control had calcium in it. We concluded that the control didn't have calcium while other groups concluded that it did have calcium. A possible reasons why it could be different are because we may have had a different control solution then the other ones in the class. Other possibilities include contamination or not properly reading chemicals. Because these are qualitative tests the interpretation of a precipitate could be different. 

Class Data: