What mass in grams of sodium carbonate, Na, Co, is produced if 50.0 g of sodium oxide, Na,0, are reacted
with excess carbon monoxide, CO, according to the fol-
lowing chemical equation? (Hint: see Sample Problem
8A.)
2Na, O(s) + CO(g) → Na, Co,(s) + Na(s)

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

the correct answer would be d. hope this !