Question #0f3a3

Nov 5, 2016

x = 10

Explanation:

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 $N {a}_{2} C {O}_{3} X {H}_{2} O$ is 106 + 18X. Thus, by definition, one mole of $N {a}_{2} C {O}_{3} X {H}_{2} O$ 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 $N {a}_{2} C {O}_{3} X {H}_{2} O$ has a mass of 106 + 18X we can calculate that X must be 10.

Therefore, the formula of the compound is $N {a}_{2} C {O}_{3} 10 {H}_{2} O$.