Question

Insulin contains $3.4\%$ sulphur by mass. What will be the minimum molecular weight of insulin?

Answer 1

The number of sulphur atoms present in the insuline is not given in the question.
Therefore, the minimum number of sulphur atoms that can be present in this molecule is one.
The molar mass of sulphur = 32 g per mole.
Let x grams be the molar mass of insulin. The mass by mass percentage is given by:
We are given that the percentage of sulphur is $3.4\%$. So,
$3.4=\left(\frac{32}{x}\right)\times 100$
Therefore, 3.4 $x=32\times 100$
x = 941.176 g
Hence, the minimum molecular weight of insulin is 941.176 g.