Tungsten has body centred cubic lattice. Each edge of the unit is 316 pm and density of the metal is `19.35"g cm"^(-3)`. How many atoms are present in 50 g of the metal ?

Explanation

Z = 2 (b.c.c. lattice)
a = 316 pm
`=3.16xx10^(-8)"cm"`
`d=19.35"g cm"^(-3)`
m = 50 g, n = ?
`d=(Zxxm)/(a^(3)xxn)`
`z=(Zxxm)/(a^(3)xxd)`
`=(2xx50g)/((3.16xx10^(-8))^(3)"cm"^(3)xx19.35"g cm"^(-3))`
`=(100xx10^(24))/((3.16)^(3)xx19.35)=(100xx10^(24))/(31.55xx19.35)`
`=1000/(31.55xx19.35)xx10^(23)=1.64xx10^(23)`