30cm³ of 2.0M hydrochloric acid completely reacts with 5.0g of impure zinc carbonate. Calculate the per centage purity of zinc carbonate. (Zn=65, C=12, O=16)
Step III
Calculate the molar mass of ZnCo₃ that reacted with Hcl.

R.A.M Zn =
R.A.M C=
R.A.M O=
RFM of ZnCo3= 65 +	=(16 x)
=
Mass of ZnCo that reacted = moles x R.F.M	= 0.03 x	=g

Step IV
Work out the per centage purity of zinc carbonate in the mixture