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the concentration of calcium in bones

the concentration of calcium in bones. Pat Benecewicz & Nathan Tompkins. Why we are doing this?. * 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.

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the concentration of calcium in bones

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  1. the concentration of calcium in bones Pat Benecewicz & Nathan Tompkins

  2. Why we are doing this? • * 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.

  3. Proposed Procedure • 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.

  4. Results

  5. Results (Cont.)

  6. Results (Cont.)

  7. Results (Cont.)

  8. Sample Calculations

  9. Discussion • 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.

  10. Discussion Cont. • 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.

  11. Discussion Cont. • 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.

  12. Any Questions?

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