Pat Benecewicz & Nathan Tompkins
* Compare concentrations of
calcium from species to species.
*Species:
•Cow
•Pig
•Deer
* The two methods will be a
whole bone soaking and a
ground-up bone soaking both
in vinegar.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Soak the bones in boiling water to take the meat off just leaving the cartilage and
bone.
Dry the bones overnight to remove any excess water off the bones.
Mass the femurs of each animal.
Put the femurs of each animal into a container and fill with vinegar to completely
cover the bones. Let them soak for a week.
Take the tibias of each animal and cut a 1 inch section from each bone.
Crush the bone using a mortor and pestle and mass 5 grams of bone from the
ground bones.
Put each 5g portion in a 150mL beaker and add 100mL of vinegar. Let them soak
for a week.
Make a .01M solution of EDTA using 1.8600g of EDTA in 500mL of DI water.
Make a .1M solution of CaCO3 using 1.000g of CaCO3 in 2M HCl. Make an
ammonia buffer with 6M NH4OH and adding 6M HCl until the pH is 10.00.
Standardize the EDTA solution with 3mL of the CaCO3, 5mL of ammonia buffer,
and 4 drops of calmagite indicator. Repeat two more times.
Remove the bones from the vinegar and allow the bones to dry. Record the
volume of vinegar used for the whole bones.
Take 5mL of the vinegar solution, 5mL of ammonia buffer, and 4 drops of
calmagite and titrate to the blue endpoint with the standardized EDTA.
Do this titration 3 times for each whole bone vinegar solution and 3 times for each
ground up bone vinegar solution.
Calculate the concentration of calcium in each vinegar solution.
Standardization
Of EDTA
First
Trial
mL EDTA
[EDTA]
1
13.09
.00916
2
15.70
.00764
3
12.91
.00929
Masses:
Bones (Type)
Mass:
Deer (Whole Bone)
108.5450
Lamb (Whole
Bone)
76.4206
Hog (Whole Bone)
292.5120
Deer (Ground Up)
4.9180
Lamb (Ground
Up)
5.0013
Hog (Ground Up)
5.0097
Average [ ]
Standard Dev.
.00870
.000917
Whole Bone
Titration
Deer
Lamb
Hog
Trail 1
39.69
45.90
20.00
Trail 2
39.89
45.90
17.75
Trail 3
40.04
45.91
17.89
% Ca2+ (Trial 1)
.012745
.020934
.002383
% Ca2+ (Trial 2)
.012809
.020934
.002115
% Ca2+ (Trial 3)
.012857
.020939
.002132
Average % Ca2+
.012804
.020936
.002210
Standard Dev.
.0000564
.00000263
.000150
Standardization
Of EDTA
Second
Trail
mL EDTA
[EDTA]
1
12.21
.02455
2
12.19
.02459
3
12.19
.02459
Average
Standard Dev.
.02458
.00002309
Ground Bone
Titration
Deer
Lamb
Hog
Trial 1
44.79
55.79
57.09
Trail 2
41.59
56.55
53.62
Trail 3
42.30
57.40
55.35
% Ca2+ (Trial 1)
.008971
.010988
.011225
% Ca2+ (Trial 2)
.008330
.011137
.010543
% Ca2+ (Trial 3)
.008472
.011305
.010883
Average % Ca2+
.008591
.011143
.010833
Standard Dev.
.000337
.000159
.000341



The purpose of this lab was to extract calcium
from bones using vinegar (acetic acid).
Acetic acid breaks apart CaCO3 in the bones
leaving the Ca2+ ion floating in the vinegar and
producing CO2 .
This was observed when bubbles were forming
around the bones when they were in the
vinegar.



We formed a hypothesis that the hog would
have the most calcium in it while the lamb
would have the least amount of calcium in it.
Our data proves otherwise. In both methods,
the lamb had the highest percent of calcium.
Grinding up the bones did not help extract
more calcium than the whole bone soak.


A precipitate formed when we added the
buffer to the vinegar. We found out that this
white precipitate was Ca(OH)2. Proving that
we had our target ion in the vinegar solution.
The precipitate disappeared once we reach the
endpoint.