Question

Insulin contains 3.4 % sulphur. Calculate the minimum molar mass of insulin.

Answer 1

There is a formula to calculate the total molar mass of a chemical and it is as follows.
$\text{Mass by mass percentage of a chemical = }\dfrac{\text{Mass of the solute}}{\text{Mass of the total chemical}}\times 100$

Complete step by step answer:
- In the question it is given that insulin contains 3.4 % of sulphur.
- We have to calculate the minimum molar mass of the insulin.
- In the question it is not given about the number of sulphur atoms present in insulin molecules.
- Then we have to consider one is the minimum number of sulphur atoms that should be present in insulin chemicals.
- We know that the molar mass of the sulphur is 32 grams per mole.
- Assume X is the grams of mass of the total chemical.
- Then substitute the known values in the below formula to get the minimum molar mass of insulin.
$\text{Mass by mass percentage of a chemical = }\dfrac{\text{Mass of the solute}}{\text{Mass of the total chemical}}\times 100$
- Mass by mass percentage of a chemical = 3.4
- Mass of the solute = 32
- Mass of the total chemical X we have to find.
- Then
$\begin{aligned} & \text{Mass by mass percentage of a chemical = }\dfrac{\text{Mass of the solute}}{\text{Mass of the total chemical}}\times 100 \\\ & 3.4=\dfrac{32}{X}\times 100 \\\ & X=941.17grams \\\ \end{aligned}$
Therefore the minimum molar mass of the insulin is 941.17 grams.

Additional information:
- Insulin is a hormone containing two peptide chains called chain-A and chain-B.
- The two chains are linked together by two disulfide bonds.
- In chain-A there are 21 amino acids and in chain-B there are 30 amino acids.

Note: Don’t be confused with solution, solvent and solute. They are not the same. Solute means a minimum amount of chemical present in a large amount of solvent. Solvent means a huge amount of chemical in it solute dissolves. Solution means a mixture of solute and solvent.