Question

A suppository contains 3 mg of prednisolone (C₂₁H₂₇O₄). What mass of prednisolone sodium phosphate (C₂₁H₂₇O₄.PO₄Na₂ MW: 484.4) would the suppository contain? Answer to 3 significant figures.

Answer 1

Mass of prednisolone sodium phosphate will be 3.410 mgs

Solution:

Atomic wt. of Oxygen 15.999. Sodium 22.989. Phosphate 30.970

So total weight of molecule of sodium phosphate will be. 140.944

Now lets assume no.of molecules of prednisolon in 3 mg is n

Mol . Wt of prednisolne alone is 343.456

Now.
n(343.456) = 3 mg

So n = 3 divided by 343.456

Now we have to find mass this of prednisolone sodium phosphate

So put the values below

n(343.456+140.944) = mass ?

Put the value of n and calulate

Answer will be 3.410 mg