Question

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Calculate the molecular masses of the following:
(i) ${\text{SO}}_2$ (ii) ${\text{CO}}_2$ (iii) ${\text{NO}}_2$ (iv) ${\text{H}}_2\text{O}$

Answer 1

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> The mass of one molecule of an element or compound is known as molecular mass. It is represented by 'u'.

Molecular mass of ${\text{SO}}_2$= Atomic mass of sulphur + 2 $\times$ Atomic mass of oxygen
Molecular mass of ${\text{SO}}_2$= $32+2\times 16$ = $64u$

Molecular mass of ${\text{CO}}_2$= Atomic mass of carbon + 2 $\times$ Atomic mass of oxygen
Molecular mass of ${\text{CO}}_2$ = $12+2\times 16$ = $44u$

Molecular mass of ${\text{NO}}_2$ = Atomic mass of nitrogen + 2 $\times$ Atomic mass of oxygen
Molecular mass of ${\text{NO}}_2$= $14+2\times 16$ = $46u$

Molecular mass of ${\text{H}}_2\text{O}$ = 2 $\times$ Atomic mass of hydrogen + Atomic mass of oxygen
Molecular mass of ${\text{H}}_2\text{O}$= $2\times 1+16$= $18u$