Question

how many moles of sodium atoms in 255 grams of na2so4

Answer 1

$M_{Na_{2}SO_{4}}=142\frac{g}{mol}\\ m=255g\\\\ n=\frac{m}{M}=\frac{255g}{142\frac{g}{mol}}\approx1,8mol\\\\ 1,8mol*2=3,6mol \ of \ sodium \ atoms$