How many unit cells are present in a cube shaped ideal crystal of NaCl of mass 1.00 g ? Atomic masses : Na=23, Cl=3.55)

How many unit cells are present in a cube shaped ideal crystal of NaCl

1.	How many unit cells are present in a cube shaped ideal crystal of NaCl of mass 1.00 g ? Atomic masses : Na=23, Cl=3.55)
Answer» `1.28times10^(21)` `1.71times10^(21)` `5.14times10^(21)` `2.57times10^(21)` Solution :Mass of ONE unit cell (m)=`"VOLUME "times "density"` =`a^(3)timesd=a^(3)times(MZ)/(N_(0)a^(3))=(MZ)/(N_(0))` `therefore m=(58.5times4)/(6.02times10^(23))G` Number of unit CELLS in `1 g=1/m` `=(6.02times10^(23))/(58.4times4)=2.57times10^(21)`