Question

Lead 2nd sulphide crystal has nacl structure wht is the distance between pb2+ and 80'2-in pbs if its density is 12.7g cm-3 atomic mass of pb =207

Answer 1

Answer:

Explanation:Molar mass of gold =197

No. Of atoms in 2g of gold

2/197*6.022*10^23

=6.1137*10^21

As the FCC contains 4 atoms

Unit cell=6.1137/4=1.528*10^21

Hence it contains. 1.528*10^21 cells