Question

1.Give two examples of polatomic ions.
2.Calculate the molecular mass of-
H2O H2SO4 HNO3 ​

Answer 1

1. Polyatomic ions are ions which consist of more than one atom. For example, nitrate ion, NO3-, contains one nitrogen atom and three oxygen atoms. The atoms in a polyatomic ion are usually covalently bonded to one another, and therefore stay together as a single, charged unit.
2. molecular mass of HNO3.

atomic mass of hydrogen=1.

atomic mass of nitrogen =14.

atomic mass of oxygen=16x3=48.

molecular mass.

=48+14+1=63u.

molecular mass of H2SO4.

atomic mass of hydrogen=1x2.

atomic mass of sulphur=16

atomic mass of oxygen=16×4(because O has 4 atoms)=64

molecular mass=64+16+2=132u