Calculate the number of atoms in a 7.45x10^3 g sample of sodium

The molecular mass of sodium = 23g

One mole of sodium consists of 23 g of sodium

One mole consists of 1 Avagadro (6.022 x 10^23 molecules) number of molecules

Therefore 23 g consists of 6.022 x 10^23 molecules of Sodium.

Hence 7.45 x 10^3 g of Sodium will consist of x no of molecules of sodium.

x no of molecules =

(7.45 x 10^3 g/23 g) x (6.022 x 10^23)

=1950.6 x 10^ 23 molecules (atoms).