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Project 16: Investigation of Kidney Stones: Formation and Di

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Ashley Haney

on 10 March 2014

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Transcript of Project 16: Investigation of Kidney Stones: Formation and Di

Project 16: Investigation of Kidney Stones: Formation and Dissolution
By: Ashley Haney, Zack Howard, Alyssa Lamb
The main goals of this experiment were to investigate the formation of kidney stones and to suggest ways to dissolve and prevent them.
Experimental Design
When trying to produce magnesium phosphate and magnesium oxalate, the magnesium stock solution wasn't reacting with the other reactants.
This left us missing two of our kidney stones for week two.
When trying to filter our kidney stones, the precipitate was too thin and seeped right through the filter paper. This forced us to centrifuge the artificial stones.
For the synthesis of calcium phosphate, we only used one fourth of our diluted solution so that it could form a precipitate in the time given for the lab period, giving us a fourth of the predicted mass of our calcium phosphate kidney stone.
Because of the small amount of calcium phosphate precipitate that we had to work with, we did not have enough of that particular artificial kidney stone to complete all of week 2's tasks. We only had enough to test how long it would take for the calcium phosphate to dissolve in lemon juice.
After centrifuging the calcium oxalate precipitate, we kept the artificial stone in the test tube for the next week. Instead of keeping it in the test tube, we should have put it on a watch glass or filter paper so that it could fully dry for week 2.
Because our precipitate wasn't fully dried, this threw off the calculations for the actual yeild for calcium oxalate. There was the mass of the water accounted in the total mass of the precipitate, which made it seem heavier than it actually was.
This also made our actual yield over 100% because the actual yield was so much greater than the theoretical yield.
In the beginning of the experiment, we initially performed our stoichiometry incorrectly. This gave us the wrong mass numbers of reactants to use and ultimately led to our reactions not forming any precipitate. We eventually caught on to our mistake and recalculated the problems to get more accurate answers. In the long run, this mistake mostly only hurt us by taking up a lot of time that we could've used to do other tasks.
When the celery seed tea was measured out from the stock solution, the solution had brown stringy substances floating around in it. We tried our best to remove the floaters, but not all were big enough to remove. This might have affected the dissolution of the artificial kidney stones.
Week 1 Results:
CaCl2 (aq) + Na2C2O4 (aq) --> CaC2O4 (s) + 2NaCl (aq)
Net ionic: Ca2+ (aq) + C2O42- (aq) --> CaC2O4 (s)
White precipitate formed, solution was cloudy
Solid calcium oxalate was formed
After Vacuum filtration, centrifuging, and dilution:
2.76g solid calcium oxalate was obtained
Percent yield: 220%

Week 1 Results continued:
3Ca(NO3)2 (aq) + 2Na3PO4 (aq) --> Ca3(PO4)2 (s) + 6NaNO3 (aq)
Net ionic: 3Ca2+(aq) + 2PO43- (aq) --> Ca3(PO4)2 (s)
Slightly cloudy white precipitate formed in solution
After Vacuum filtration, centrifuging, and dilution:
0.76g solid calcium phosphate was obtained
Percent yield: 60.8%

Week 2 Results:
5 methods of dissolving kidney stones:
Hydochloric acid
Took 4.3 mL of 3M HCL to dissolve 0.111g CaC2O4 (s)
Lemon juice
0.1g Ca3(PO4)2 (s) dissolved in 50 mL lemon juice in 10 min
0.131g CaC2O4 (s) dissolved in 50 mL lemon juice in 30 min
0.145g CaC2O4 (s) dissolved in 9.2 mL 0.05M EDTA
Olive Oil
0.2g CaC2O4 (s) dissolved in 50 mL olive oil in 30 min
Celery Seed Tea
0.376g CaC2O4 (s) dissolved in 75 mL celery seed tea in 30 min

In preparation for this lab, our group had to do independent research on kidney stones.

The most common types of kidney stones are:
· Calcium Oxalate: Accounts for 70% of all kidney stones (CaC2O4)

· Calcium Phosphate: Accounts for 10% of all kidney stones (Ca3(PO4)2)

· Struvite: Accounts for 10% of all kidney stones and is composed of calcium, ammonia, and phosphate

· Uric Acid: Accounts for 5-10% of all kidney stones (C5H4N4O3)

We decided to synthesize both the Calcium Oxalate and the Calcium Phosphate stones
· Struvite was too difficult to synthesize

· Uric Acid stones are not within our ability to synthesize

We decided to also make Magnesium Oxalate and Magnesium Phosphate stones
· Magnesium and Calcium have very similar properties so they should be interchangeable in each synthesis equation
Formation of Stones
· Our goal was to make 5g of synthetic stones so stoichiometry was used in order to find the amounts of reactants needed to reach this goal
Calcium Oxalate:

o Dissolved 4.33g of Calcium Chloride (CaCl2) in 10 mL of water

o Dissolved 5.23g of Sodium Oxalate (Na2C2O4) in 10 mL of water

o We then mixed the two aqueous solutions to form a precipitate

Calcium Phosphate

o Dissolved 7.935g of Calcium Nitrate (Ca(NO3)2) in 10 mL of water

o Dissolved 5.285g Sodium Phosphate (Na3PO4) in 10 mL of water

o We then mixed the two aqueous solutions to form a precipitate

Magnesium Stones would not form a precipitate like they should have so these reactions were disregarded.
The solutions were then filtered by vacuum filtration but the precipitates went through the filter paper

The solutions were then placed in test tubes and centrifuged so that the precipitates would gather at the bottom of the test tubes

The fluid was then drained and our synthetic stones were allowed to dry for a week.

Week 2
Dissolving stones
· We decided at the beginning of the experimentation process that strong acids would work best in dissolving kidney stones because they have a high Ka

· Strong acids dissociate completely in water allowing them to contribute more protons to the kidney stone samples

· This would make the stone molecules positive and allow them to be dissolved in water more easily by making bonds with the negative ends of water molecules

· Adding acids with a high Ka increased the Ksp of the kidney stones.

Titrations: We used burettes to add small amounts of Hydrochloric acid and EDTA to Calcium Oxalate stone samples
***We did not have enough Calcium Phosphate to perform these reactions

1. HCl
o We added 3M HCl to a .111g sample of the Calcium Oxalate
o It dissolved with 4.3 mL added to it

o We added .05M EDTA to a .145g sample of Calcium oxalate
o It dissolved with 9.2 mL added to it
Stir tests: the sample stones were submerged in different liquids and continuously stirred until they completely dissolved

1. Lemon Juice
o Dissolved .1g Calcium Phosphate in 50 mL of lemon juice
It dissolved in about 10 minutes
o Dissolved .131g Calcium Oxalate in 50 mL of lemon juice
It dissolved in about 30 minutes

2. Olive Oil: Did not have Calcium phosphate for this experiment
o .2g Calcium oxalate dissolved in 50 mL of olive oil in 30 minutes

3. Celery seed tea: Did not have Calcium phosphate for this experiment
o .376g Calcium Oxalate dissolved in 75 mL of celery seed tea in 30 minutes

Fun fact: The largest known kidney stone weighed 1.36 kilograms
Calcium Oxalate
Calcium Phosphate
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