Lab Report: Water Testing

LAB REPORT

Water Testing

6/25/13

Charlie, Ben, Georgie

Summer 2013

Dr. Foreman

PURPOSE: 

The purpose of this lab was to learn how to test the presence of dissolved ions in different kinds of water including; distilled water, reference solution, control solution, tap water, and natural water (ocean water). And by doing this, we learned a lot about ions.

ABSTRACT:

In this experiment, we tested for the presence of different ions through tests that confirms the presence of ions, otherwise known as confirming tests. My team and  I preformed four different tests  to test for the presence of dissolved calcium, iron, chloride, and sulfate ions. We would test for the these ions by using 5 five different solutions: distilled water, reference solution, control solution, tap water, and natural water (ocean water). By testing for ions with these different types of solutions, my team and I hoped we would be able to see which types of solutions had a change in color or  had an appearance of participate, or even no reaction at all. These tests are important to help us reach a conclusion to what contaminates our water, and can therefore go through the necessary processes needed to purify the water.

PROCEDURE:

•  Calcium Ion Test:
•  Place 20 drops of distilled water into a 24-well plate
•  Place 20 drops of reference solution (Ca Chloride) into a 24-well plate
•  Place 20 drops of control solution into a 24-well plate
•  Place 20 drops of Tap water into a 24-well plate
•  Place 20 drops of Natural water into a 24-well plate
• 
  

•  Add 3 drops of sodium carbonate test solution to each of the wells
• Record your observations in your data table
• Decide whether CA2+ cations are present and record your results
• Discard the contents of the well plates as directed by your teacher

• Iron Ion Test
•  Place 20 drops of distilled water into a 24-well plate
•  Place 20 drops of reference solution (Ferric Nitrate) into a 24-well plate
•  Place 20 drops of control solution into a 24-well plate
•  Place 20 drops of Tap water into a 24-well plate
•  Place 20 drops of Natural water into a 24-well plate
• 
  

•  Add one to two drops of potassium thiocyanate test reagent to each of the wells
• Record your observations in your data table
• Decide whether Fe3+ cations are present and record your results
• Discard the contents of the well plates as directed by your teacher

• Chloride Ion Test
•  Place 20 drops of distilled water into a 24-well plate
•  Place 20 drops of reference solution (Ca Chloride) into a 24-well plate
•  Place 20 drops of control solution into a 24-well plate
•  Place 20 drops of Tap water into a 24-well plate
•  Place 20 drops of Natural water into a 24-well plate
• 
  

•  Add 3 drops of silver nitrate test reagent to each of the wells
• Record your observations in your data table
• Decide whether Cl- anions are present and record your results
• Discard the contents of the well plates as directed by your teacher

• Sulfate Ion Test
•  Place 20 drops of distilled water into a 24-well plate
•  Place 20 drops of reference solution (Ferric Nitrate) into a 24-well plate
•  Place 20 drops of control solution into a 24-well plate
•  Place 20 drops of Tap water into a 24-well plate
•  Place 20 drops of Natural water into a 24-well plate
•  Add 3 drops of barium carbonate test solution to each of the wells
• Record your observations in your data table
• Decide whether SO4^2- anions are present and record your results
• Discard the contents of the well plates as directed by your teacher

RESULTS:

After my team and I preformed 4 different tests to test for the presence of dissolved calcium, iron, chloride, and sulfate ions, we were able to see which types of solutions had a ion appearance. And after filling out our data table, we are able to conclude that in the calcium ion test there was no presence of calcium ions in the distilled water, tap water, or control solution; however, in the reference solution and the natural water there was a presence of theses ions. In the iron ion test, we were able to conclude that there was no presence of iron ions in the distilled water, the natural water, and the reference solution; however, in the control solution and the tap water there was a presence of these iron ions. In the chloride ion test, we concluded that there was no presence of chloride ions in distilled water and natural water, on the other hand, there was a presence of these chloride ions in the reference solution, the control solution, and tap water. Finally, in our sulfate ion test, we were able to conclude that there was no presence of sulfate ions in the distilled water and the tap water; therefore, there was a presence of these sulfate ions in the reference solution, the control solution, and the natural water. Overall, I think my group and I worked better than we ever had. We were more organized than before, by assigning specific jobs to each other, and by listening to what we each had to say. Although we were confused on what to do in the beginning, we worked hard with each other, and created a better understanding of what we had to do to make this lab successful.

Data Table: Calcium Ion Test:

Data Table: Iron Ion Test:

Data Table: Chloride Ion Test:

Data Table: Sulfate Ion Test:

Class results:

For the class results, we focused mainly on the results from the control solution and the ocean water. From these results we created a histogram, with all of the classes data together. From the histogram, I was able to conclude that many groups had the same results, and many groups had a variety of results. Most groups for their calcium test got no appearance of calcium ion for there control substance, and a variety got yes for ion appearance in there ocean water. For the iron test, most groups got no for ion appearance in the control substance, and all groups got no for ion appearance for ocean water. For the chloride test, there was a variety for the appearance or no appearance of the chloride ion in the control substance; however in the ocean water, most groups did have the appearance of the chloride ion. For the sulfate test, all groups got the same results, which was there was an appearance of sulfate ions in both the control solution and the ocean water. I think the variety of results has to do with how well each group rinsed their wells after each test, and how much of each solution they used.

Lab Questions #1-4:

1. A reference solution is a solution of known compositions used as a comparison. There were both reference and blank solutions in each test to give us something to compare our results to.

2. Some possible problems associated with the use of qualitative tests are that these tests only test for the presence or absence of a substance, not the amount of the substance. Also a problem that may arise from this kind of test is that sometimes water may appear pure, and but can actually be contaminated. 

3. These tests cannot absolutely confirm the absence of an ion because sometimes a negative test might mean an ion is not present, or the ion is present in such a low amounts.

4. Our observations might have changed if we had not cleaned our wells or stirring rods thoroughly after each test because our observations would have been falsely impacted by the previous substances; therefore, giving us false results.