water testing lab report

Nina Gabbay

Summer Chemistry

Dr. Forman

Group Lithium: Nina, Nicolette, Makena 

Water Testing Lab Report

It’s no myth, call us Lith. 

Don’t stop pour that drop, see that color change then stop. Get a table, write results, grab your group and then consult. Are there ions, are there not, it interests me a lot. 

Abstract: 

The purpose of this experiment is the test water to learn about precipitate and to detect invisible ions through the tests. Although the foul water lab only had 3 main steps, the water testing lab included four main steps: calcium ion test, iron ion test, chloride ion test, and sulfate ion test. In each test, we poured 5 different samples: the reference, the control, the tap water, the ocean water, and the distilled water. Through those steps we discovered that each water source reacted the same or differently than others after dropping ions in each substance. Ions were present in some sources, but not visible in others. 

Procedure: 

In this lab, teamwork was essential; the lab forced all group members to each take an a specific responsibility in order to accomplish our goals for the experiment. The materials we used were a beaker, wellplate, glass stirring rod, and a pipet. We decided to always make the first hole of the well the reference, the second hole the control, the third hole the tap water, the fourth hole the ocean water, and lastly, the fifth hole the distilled water. This system allowed us to stay on task and be organized throughout the whole lab. 

The first was the Calcium Ion test. We filled the first well with calcium chloride, the second with the control, the third with tap water, the fourth with ocean water, and the fifth with distilled water. After adding three drops of sodium carbonate for each source of water, we found different results. The tap water and the distilled water both turned pink. However, we then observed that our results were different from everyone else; therefore, we arrived at the conclusion that the group prior to us did not clean their well. At first we were a little bothered but quickly washed the well and started over. After starting over, our results slightly differed. The reference solution (calcium chloride) became cloudy and white with precipitates, the control remained clear with no precipitate, the tap water turned unusually pink with precipitates, and the ocean water and distilled water remained clear with no precipitate. Thus, calcium ions were present in the reference and the tap water but not in the control, ocean water, or the distilled water. 

Washing the well after the different result: 

Before sodium carbonate: 

After sodium carbonate: 

The second test was the Iron Ion test. We filled the first well with ferries nitrate, the second with the control, the third with tap water, the fourth with ocean water, and the fifth with distilled water. We made sure to use the one pipet for each substance so that we do not contaminate any which would change our results. After adding one to two drops of potassium thiocyanate, the results were different. The reference solution (ferris nitrate) turned from a yellow color to a deep redish black color with precipitate present. The control solution, tap water, ocean water, and distilled water all remained clear with no precipitate. Thus, iron ions were only present in the reference solution. 

Before potassium thiocyanate: 

After potassium thiocyanate: 

The third test was the Chloride Ion test. We filled the first well with calcium chloride which was the same reference solution we used for the calcium ion test. We then filled the second well with the control, the third with tap water, the fourth with ocean water, and the fifth with distilled water. After adding three drops of silver nitrate, we observed that more precipitate and ions were present than the calcium ion and iron ion test. The reference solution (calcium chloride) turned from a clear substance to a cloudy and milky substance with precipitate present. The tap water and ocean water also turned cloudy and more foggy with precipitate present. The control solution and the distilled water remained clear with no precipitate present. We realized that in all the tests so far, the control solution and the distilled water remained clear with no precipitate and no ions present. Therefore, chloride ions were only visible in the reference solution, tap water, and the ocean water. 

Before silver nitrate: 

After silver nitrate: 

Our fourth and final test was the Sulfate Ion test. After each test we made sure to wash the well plate very well because we did not want our results to be different like they were the first time. So after washing the well plate, we filled the first well with ferrous sulfate, the second well with the control, the third with tap water, the fourth with ocean water, and the fifth with distilled water. After adding three drops of barium chloride, we observed the color change and precipitates present for one last time. The reference solution (ferrous sulfate) became like a milky and cloudy yellow color with precipitate present. The control solution and ocean water also became cloudy with precipitates present, but the tap water and distilled water remained clear with no precipitates. Therefore, sulfate ions were visible in the reference solution, the control solution, and the ocean water. 

Before barium chloride: 

After barium chloride: 

Results: 

Calcium Ion Test: 

Solution	Observations (color, precipitate)	Result (ions present?)
Reference	Cloudy, precipitate present.	ions present
Control	Clear, no precipitate present.	ions absent.
Tap water	Pink, precipitate present.	ions present
Ocean water	Clear, no precipitate present.	ions absent.
Distilled water	Clear, no precipitate present.	ions absent.

Iron Ion Test: 

Solution	Observations (color, precipitate)	Result (ions present?)
Reference	Deep red color, like blood orange, precipitate present.	ions present
Control	Clear, no precipitate present.	ions absent.
Tap water	Clear, no precipitate present.	ions absent.
Ocean water	Clear, no precipitate present.	ions absent.
Distilled water	Clear, no precipitate present.	ions absent.

Chloride Ion Test: 

Solution	Observations (color, precipitate)	Result (ions present?)
Reference	Cloudy, precipitate present.	ions present
Control	Clear, no precipitate present.	ions absent.
Tap water	A bit cloudy, precipitate present.	ions present
Ocean water	Cloudy, precipitate present.	ions present
Distilled water	Clear, no precipitate present.	ions absent.

Sulfate Ion Test: 

Solution	Observations (color, precipitate)	Result (ions present?)
Reference	Cloudy, yellowish color, precipitate present.	ions present
Control	Cloudy, precipitate present.	ions absent.
Tap water	Clear, no precipitate present.	ions present
Ocean water	Cloudy, precipitate present.	ions present
Distilled water	Clear, no precipitate present.	ions absent.

Class results: 

For the ocean water, chloride and sulfate ions were present. But for the class, some groups had calcium ions present. 

For the control, sulfate ions were present. But for some groups, chloride and iron ions were present. 

For the reference, calcium, iron, chloride, and sulfate ions were present. 

The results for each group might have been different because each table maybe had a slight different solution which caused the results to differ.

Questions: 
1) A reference solution was used in order to see what reaction happens with a high value of the ions being tested. A blank was used to show that there is no reaction when the ion being tested for is not present in the solution.
2) Some possible problems associated with qualitative tests are that they cannot confirm ions are not  present and qualitative tests only test for the presence or absence of a substance, not the amount of the substance. 

3) These tests cannot absolutely confirm the absence of an ion because sometimes, the ion is present in such small amounts, it is not detected through the tests. 

4) If the wells are not cleaned, the results can be contaminated and therefore, incorrect data. This actually happened to our group because the group prior to ours did not clean their well plate well enough. Although the results for the first test was initially ruined, we cleaned the well plate in order to get accurate results. 

This experiment was very valuable and interesting to me. It made me realize that you can take any water sample, for example from Buckley’s turtle pond, and see what ions are present. Therefore, while initially I never thought I could test for ions myself, I then realized how simple it really is.