Question #0f3a3

1 Answer
Nov 5, 2016

x = 10


The molecular weight of anhydrous sodium carbonate is 106 and the molecular weight of water is 18. Therefore, the formula for the molecular weight of #Na_2CO_3 XH_2O# is 106 + 18X. Thus, by definition, one mole of #Na_2CO_3XH_2O# will have a mass of 106 + 18X.

Given that 107.25 g of the compound is equal to 0.375 mol, then 1 mole of the compound will have a mass of 286 g.

(Mass of compound = #107.25//0.375# = 286 g)

Therefore, knowing that one mole of #Na_2CO_3 XH_2O# has a mass of 106 + 18X we can calculate that X must be 10.

Therefore, the formula of the compound is #Na_2CO_3 10H_2O#.