Question

A substance has 16% by mass of sulphur and 4% by mass of oxygen calculate minimum molar mass of substance

Answer 1

The compound has sulphur=16%

∴ 16g of S is present in 100g

∴ 32g of S is present in = 32×100/16=200

[Least molecular mass means that at least one atom of sulphur should be present in molecule]

Answer 2

Answer:

The minimum molar mass of the substance will be 600g.

Explanation:

Consider that the mass of the substance = 100g

Mass of the sulphur will be = 16g

Mass of oxygen = 4g

Number of moles of Sulphur $=\frac{16}{32}=0.5 mol$

Number of moles of oxygen $=\frac{4}{16}=0.25mol$

Molar mass of substance due to S = mass/no. of moles

                                                         $=\frac{100}{0.5}=200g$

Molar mass of substance due to O $=\frac{100}{0.25}=400g$

The minimum molar mass of substance = 200 +400 = 600g

Therefore, the minimum molar mass of the substance is equal to 600g.