# A 3.09-gram sample of a mixture of KCl and KClO3 is decomposed by heating and produces 169 mL of...

## Question:

A 3.09-gram sample of a mixture of {eq}KCl {/eq} and {eq}KClO_3 {/eq} is decomposed by heating and produces 169 mL of {eq}O_2(g) {/eq} measured at 23.5 degrees Celsius and 746 mmHg. What is the mass percent of {eq}KClO_3 {/eq} in the mixture?

{eq}2KClO_3(l) \to KCl(s) + 3O_2(g) {/eq}

## Stoichiometry:

In a reaction which has gaseous species, they are often expressed in volume which can be converted into number of moles using the ideal gas equation. The number of moles of the gas can be used to convert stoichiometrically to the desired species. In this case, the measured species is oxygen. From here, the mass of potassium chlorate from the mixture can be obtained.

## Answer and Explanation: 1

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The first thing to calculate is the number of moles of oxygen. This can be calculated using the ideal gas equation. It can be assumed that the...

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