Solid potassium chlorate (kclo3) decomposes into potassium chloride and oxygen gas when heated. how many moles of oxygen form when 54.3 g completely decomposes?

The formula for potassium chlorate is: 2KClO₃ → 2KCl + 3O₂

If moles = mass : molar mass

then moles of KClO₃ = 54.3 g : [ (39 * 1) + (35.5 * 1) + (16 * 3) ] g/mol

= 54.3 g : (122.5 g) g/mol

= 0.4433 mol

Now the mole ratio of KClO₃ : O₂ is 2 : 3

∴ if moles of KClO₃ = 0.4433 mol

then moles of O₂ = (0.4433 mol : 2) * 3

= 0.6649 mol

Now since mass = moles * molar mass

∴ the mass of oxygen produced = 0.6649 mol * (16 * 2) g/mol

= 21.277 g

∴ the grams of oxygen gas produced when 54.3 grams of potassium chlorate is decomposed is ~ 21.28 g.