What is the percent by mass of potassium in cap k sub 3 cap f e cap c cap n sub 6 ? Use percent Element is equal to total mass of element in compound over molar mass of compound times 100

The formula K₃Fe(CN)₆ contains 3 potassium atoms, so potassium contributes 3 × 39.10 = 117.30 g per mole of compound. The molar mass is 3(39.10) + 55.85 + 6(12.01) + 6(14.01) = 329.27 g/mol. Thus, the percent by mass of potassium is (117.30 ÷ 329.27) × 100 ≈ 35.62%, which is choice D, 35.62%.

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