What is the mass percentage composition of potassium in saltpeter, $K N O_{3}$ $KNO_3$ ?

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Answer 1 · 2017-08-18T05:49:43

$% K$ $%K$ by mass in $K N O_{3} = \frac{Mass of metal}{Mass of compound} \times 100 %$ $KNO_3="Mass of metal"/"Mass of compound"xx100%$

And thus...............we interrogate the molar masses of the compound, and of potassium.....

$K % = \frac{39.1 \cdot g \cdot m o l^{- 1}}{101.1 \cdot g \cdot m o l^{- 1}} \times 100 % ≅ 39 %$ $K%=(39.1*g*mol^-1)/(101.1*g*mol^-1)xx100%~=39%$

How did I know the atomic mass of potassium?

What is the mass percentage composition of potassium in saltpeter, KNO3KNO_3?