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Unformatted text preview: difference being careful not to touch the vial containing the
calcium carbonate with your fingers. Use a small piece of folded paper wrapped
around the vial to handle the sample. Find the initial mass of vial; dispense the solid
in a 250 mL Erlenmeyer flask; and reweigh the vial. Record the precise masses in
your notebook. Calcium carbonate is insoluble in water. To dissolve the sample, add
about 20 mL of deionized water to it and then slowly add 6 M HCl drop-wise. You 25 will observe the evolution of CO2 gas as the carbonate reacts with the HCl. It will
take approximately 6-15 drops of HCl to neutralize the sample and dissolve it. Do
not over acidify.
Question A: Write the balanced chemical equation for the standardization of EDTA
It is absolutely essential that the pH of the calcium carbonate solution remain at 10
throughout the titration. To ensure that the pH remains at 10, in the fumehood add an
additional 5 mL of the ammonia buffer (found in the fumehood) and another 30 mL
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This note was uploaded on 04/09/2013 for the course CHE CHE 2C taught by Professor Nasiri during the Spring '07 term at UC Davis.
- Spring '07