Question

calculate the molar mass of Pb(NO3)2

Answer 1

Mass of Pb= 207
Mass of N=14
and of O=16
Therefore molar mass=207+(14×2)+(6×16)=331 u
or 331 gmu

Answer 2

Answer: calculate the percentage of water of crystallization in hydrated copper sulphate [CuSO4.5H2O.[Cu=64;S=32;O=16;H=1]

Explanation: g -molecular weight of CuSO4.5H2O=1(Cu)+1(S)+4(O)+5(H2O)

=1(64)+1(32)+4(16)+5(18)

=64+32+64+90=250g

G -molecular weight of five molecules of water=5(18)=90g.

Therefore percentage of water crystallization inCuSO4.5H2O.=90/250×100=36%.