A.Mg B.1/Mg C.M/6.02×1023g D.6.02×1023/Mg
A.1/2 B.1/5 C.1/12 D.1/15
A.Vρ/(MV+2240) B.1000Vρ/(MV+2240) C.MV/22.4(V+0.1)ρ D.1000VρM/(MV+2240)