Determine the formula of the compound: potassium – 38.64%, nitrogen – 13.86%, oxygen – 47.5%.

Let us define the formula of the compound KxNyOz. Let’s draw up an equation as the ratio of the percentage and atomic mass of an element:
x: y: z = 38.64 / 39: 13.86 / 14: 47.5 / 16.
x: y: z = 0.99: 0.99: 2.97.
Let’s convert to an integer relation:
x: y: z = 1: 1: 3.
Accordingly, the formula of the substance is KNO3 (potassium nitrate).

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