Question

calculate the mass of sodium which contains the same number of atoms present in 4g of calcium?

Answer 1

Moles of Ca in 4 g sample = Given mass of Ca/ Molar mass of Ca
= 4 g / 40 g mol^-1
​ = 0.1 mol
​Mass of 0.1 mole Na = Number of moles x Molar mass of Na
= 0.1 mol x 23 g mol^-1
​ = 2.3 g
So 4 g Ca will contain same number of atoms as 2.3 g Na.