NEET-XII-Chemistry
c2022 year:2022
- #47Copper crystallises in fcc unit cell with cell edge length of `` 3.608 \times 10^{-8} cm `` . The density of copper is `` 8.92 \,g\, cm ^{-3} `` . Calculate the atomic mass of copper.
(A) `` 65 \,u ``
(B) `` 63.1\, u ``
(C) `` 31.55 \,u ``
(D) `` 60\, u ``digAnsr: BAns : `` d =\frac{ Z \times M }{ N _{ A } \times a ^{3}} ``
`` 8.92=\frac{4 \times M }{6.022 \times 10^{23} \times\left(3.608 \times 10^{-8}\right)^{3}} ``
`` M =\frac{8.92 \times 6.022 \times 10^{23}}{4} \times 46.96 \times 10^{-24} ``
`` M =63.1\, g / mol `` (Molar Atomic Mass)
`` M =63.1 \,u `` (Atomic Mass)