The hormone, thyroxine is secreted by the thyroid gland, and has the formula: c15h17no4i4. how many milligrams of iodine can be extracted from 15.0grams of thyroxine?

9.73 grams of iodine

Explanation:

First we calculate the molar mass of the tyroxine C₁₅H₁₇NO₄I₄:

M = 15 × 12 + 17 × 1 + 1 × 14 + 4 × 16 + 4 × 127 = 783 g/mole

The taking in account that 1 mole of tyroxine have 4 moles of iodine atoms (508 g) we devise the following reasoning:

if from   783 g of tyroxine we can extract 508 g of iodine

the from  15 g of tyroxine we can extract X g of iodine

X = (15 × 508) / 783 = 9.73 grams of iodine

that's what i got you can count the number of atoms