Question

A compound contains $3.2$ by mass of oxygen Write the minimum molecular weight of the Compound ?

• A. $300\text{u}$
• B. $440\text{u}$
• C. $350\text{u}$
• D. $500\text{u}$

Answer 1

The correct option is D $500\text{u}$

Let the mass of the compound be $100\text{g}$.

For the minimum molecular weight, there must be at least 1 atom of oxygen present in a molecule of the compound.

So, $3.2\text{g}$ of $O$ is present in $100\text{g}$ of the compound. (given).

Therefore, $16\text{g}$ of $O$ is present in $=\frac{100}{3.2}\times 16=500\text{g}$.

So, the molecular weight is $500\text{u}$.