Question

A solution is made by dissolving lead nitrate in water.

6.62g of lead nitrate are dissolved in water. The volume of the solution is made up to

250 cm 3 . Calculate the concentration, in mol dm –3 , of lead nitrate Pb(NO 3 ) 2 , in this solution. (relative

atomic masses: Pb = 207, N= 14,O=16)

Answer 1

solution-

Moles of Pb is$\frac{(6.62)g}{(331.2)g}$  per mole = 0.02 moles 

250 cm$^3$ to dm$^-3$ is 0.25 dm$^-3$

Concentration in mol dm$^-3$ = moles per litre =  $\frac{0.02 moles}{ 0.25 dm^-3}$   =  0.08 mol dm –3