You are completing an internship in a hospital medical anaylsis lab. A patient h

Question

You are completing an internship in a hospital medical anaylsis lab. A patient has volunteered to let you calculate the amount of Ca+2 in her blood to help you pass. You take a vial containing 2.00 mL sample of her blood into the lab for complexometric titration anaylsis with EDTA and Eriochrome Black T indicator. You reach the endpoint after addition of 2.53 mL of .00179 M EDTA. Calculate the amount of Ca+2 (not CaCO3) in your patient's blood in units of ppm. Normal blood calcium levels are between 90-110 ppm. Is your patient within this range?

I got 71.83 ppm but I am not sure if this is correct!

Explanation / Answer

Ca2+ + EDTA4- => Ca(EDTA)2-

Moles of Ca2+ = moles of EDTA4-

= volume x concentration of EDTA

= 2.53/1000 x 0.00179 = 4.5287 x 10^(-6) mol


Mass of Ca2+ = moles x molar mass of Ca

= 4.5287 x 10^(-6) x 40.08 = 0.00018151 g


Mass of blood = volume x density of blood (assume density equal to water)

= 2.00 x 1.00 = 2.00 g


Concentration of Ca2+ in ppm = mass of Ca2+/mass of blood x 10^6

= 0.00018151/2.00 x 10^6

= 90.8 ppm (or approximately 91 ppm)

So yes, the patient is in the normal range of 90-110 ppm.

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.