Molar mass of sodium sulfate is 2MNa + MS + 4MO (Get M's off of PT)
fraction of Na in sodium sulfate is 2MNa / MNa2SO4 (let's call it f ) which is grams per gram or kg per kg
Use factor labeling. Start with what you know, cancel units, put in values that make the denominator and the numerator of the multiplying fraction "equal" (in this case 1kg of compound has f kg of Na)
100 kg Na ( 1 kg compound/ f kg Na) in order to get kg of compound (Note that the units tell you to divide.
Good luck!
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