Question

Calculate the molecular weight of the following

Lead nitrate $\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$

Answer 1

Definition of molecular weight

Molecular weight, also called molecular mass, is the mass of a molecule of a substance, based on 12 as the atomic weight of carbon-12. It is calculated in practice by summing the atomic weights of the atoms making up the substance's molecular formula.

Calculation

$$\begin{gathered} \mathrm{Molecular}\mathrm{weights}\mathrm{of}: \\ \mathrm{Pb}=207 \\ \mathrm{N}=14 \\ \mathrm{O}=16 \end{gathered}$$

The molecular weight = $207+2\times (14+3\times 16)=331$

The molecular weight of $\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$= 331 amu.