Question

Insulin contains 3.4% of sulphur.Calculate the minimum molecular weight of insulin.

Answer 1

3.4g S= 100g insulin

therefore, 32g S = 100×32 / 3.4

                           941.176

Insulin must contain at least one atom of S i.e 941.176 in its one molecule.

Answer 2

For Insulin solution with 3.4% of sulphur the minimum molecular weight of insulin was calculated as 941.1 g.

Given:

Mass by mass percentage of a solution (sulphur) = 3.4%

Molar mass of Sulphur (mass of solute) = 32g

To find:

Minimum molecular weight of insulin.  

Formula to be used is used:

Mass by mass percentage of a solution $=\frac{\text { Mass of solute }}{\text { Mass of solution }} \times 100$

Solution:

Mass by mass percentage of a solution $=\frac{\text { Mass of solute }}{\text { Mass of solution }} \times 100$

$3.4=\frac{32}{\mathrm{x}} \times 100$

$3.4 \times \mathrm{x}=32 \times 100$

$\mathrm{x}=\frac{32 \times 100}{3.4}$

$\mathrm{x}=\frac{3200}{3.4}$

x = 941.1 g