Question

The hormone thyroxine is secreted by the thyroid gland and has the formula: C15H17NO4I4. How many milligrams of Iodine can be extracted from 15.0 grams of thryoxine?

Answer 1

Answer : The mass of iodine extracted can be 9796.7 mg

Explanation : Given,

Mass of thryoxine = 15.0 g

Molar mass of thryoxine = 776.86 g/mole

The molecular formula of thryoxine is, $C_{15}H_{11}NO_4I_4$

In $C_{15}H_{11}NO_4I_4$ compound, there are 15 moles of carbon, 11 moles of hydrogen, 1 mole of nitrogen, 4 moles of oxygen and 4 moles of iodine.

First we have to determine the moles of thryoxine.

$\text{Moles of thryoxine}=\frac{\text{Mass of thryoxine}}{\text{Molar mass of thryoxine}}=\frac{15.0g}{776.86g/mole}=0.0193moles$

Now we have to determine the moles of iodine.

As, 1 mole of thryoxine has 4 moles of iodine

So, 0.0193 mole of thryoxine has $4\times 0.0193=0.0772$ moles of iodine

Now we have to determine the mass of iodine.

$\text{Mass of iodine}=\text{Moles of iodine}\times \text{Molar mass of iodine}$

$\text{Mass of iodine}=(0.0772mole)\times (126.9g/mole)=9.7967g=9796.7mg$

conversion used : (1 g = 1000 mg)

Therefore, the mass of iodine extracted can be 9796.7 mg

Answer 2

I'm pretty sure it's 9726 milligrams of iodine. Hope this helps.