In an experiment, potassium chlorate decomposed according to the following chemical equation. kclo3 → kcl + o2 (molar mass of kclo3 = 122.5 g/mol; kcl = 74.55 g/mol; o2 = 31.998 g/mol) if the mass of kcl produced was 180 grams, which of the following calculations can be used to determine the mass of potassium chlorate decomposed?

Answer : The mass of potassium chlorate decomposed is 295.715 g.

Solution : Given,

Molar mass of = 122.5 g/mole

Molar mass of = 74.55 g/mole

The mass of   = 180 g

First we have to calculate the moles of KCl produced.

Now put all the given values in above expression, we get

The balanced chemical reaction is,

From the given reaction, we conclude that

2 moles of KCl produced from 2 moles of

2.414 moles of KCl produced from = 2.414 moles of

The moles of = 2.414 moles

Now we have to calculate the mass of

Mass of = Moles of × Molar mass of = 2.414 moles × 122.5 g/mole = 295.715 g

Therefore, the mass of potassium chlorate decomposed is 295.715 g.