Possible factors affecting absorbance readings of potassium permanganate solutions were investigated.
Parameters studied include water sources and the potassium permanganate precipitate age. Various concentration of potassium permanganate solutions were prepared, with different water sources, and their absorbance measured in timed intervals. By eliminating potential factors of degradation through experiments, it was concluded that the deionized water was the biggest factor affecting the degradation of potassium permanganate.
To eliminate potential factors of the degradation of potassium permanganate, process of elimination was employed. By changing one factor at a time, research was conducted to understand which factor brought in the most change. Potential factors include:
As written above, four different waters were used to test the degradation of
KMnO
4
.
When the source of water was changed, there was a difference in the degradation.
• Using Ultra-Pure water showed little to no change in the absorbance levels of potassium permanganate.
• Using the water effected by the Thomas fire showed escalated degradation as the water possibly contained organics to react with the potassium permanganate.
• Using the new deionized water also showed degradation, similar to the water effected by the Thomas fire.
• Using the old-deionized water also showed degradation, although the change was less than the other two water listed above.
After multiple experiments with different factors, it was determined that the source of water was the biggest factor in the degradation of potassium permanganate.
This was concluded after seeing that changing factors such as UV light, instrument, and source of powder showed no noticeable difference in the degradation of potassium permanganate. Only when the water source was changed we were able to see different degradation results. Through graphs, it was found that the reaction was first order. The graphs are shown below. Determining that the reaction is first order, it can be said that it is potassium permanganate reacting with organics in the water that is causing the degradation.
• UV Light
• Instrument
• Source of Potassium Permanganate Powder
• Source of Water
• Ultra-Pure
• Deionized Water before school ‘fixed’ the tank
• New deionized water
• Water effected by Thomas Fire
Each experiment had a variable of the each factor, and each factor was eliminated when it still showed degradation of the potassium permanganate powder.
Three out of the four factors – UV light, instrument, source of
Potassium Permanganate Powder – was eliminated when it was discovered that the potassium permanganate was still degrading at the same rate. However when the source of water was tested, the degradation of potassium permanganate was either halted or preserved.
0,25
0,2
0,15
0,1
0,05
0
0
-0,05
0,45
0,4
0,35
0,3
A detailed graph posted below shows the difference in degradation depending on the water source.
Sam .00016
Diana .00016
Claire .00016
Линейная (Sam
.00016)
Линейная
(Diana .00016)
-0,5
-1
-1,5
-2
-2,5
0
0 ln A vs Time (Old-Deionized Water)
20 40 60 80 100 120 140 160 180 200
Times (Hours)
1/A vs Time (New Deionized Water)
10
9
8
7
6
5
4
3
2
1
0
0 20 40 60 80 100
Time (Hours)
120 140 160 180 200
0,3
0,25
0,2
0,15
0,45
0,4
0,35
0,1
0,05
0
0
Absorbance vs Time (New Deionized
Water)
20 40 60 80 100
Time (Hours)
120 140 160 180 200
0,07
0,06
0,05
0,04
0,03
1 2 3 4 5 6
Days
7
Sam .000032 M
Diana .000032 M
Claire .000032 M
Линейная (Sam .000032 M)
Линейная (Diana .000032 M)
Линейная (Claire .000032 M)
As using Ultra-Pure water showed the minimal change in absorbance levels, it can be concluded that using Ultra-Pure water or proper de-ionized water is ideal when conducting this experiment. Using contaminated water can show escalated degradation of potassium permanganate. As the degradation of the potassium permanganate is substantial in the first three days, it can be concluded that the experiment should be conducted on the day the solution is made to get more accurate results.
0,02
0,01
0
0
-0,01
1 2 3
Days
4 5 6 7
As shown in the graphs to the left, the old-deionized water had the least effect on the degradation of potassium permanganate