potassium chlorate decomposes into potassium chloride and oxygen gas when heated. in one experiment, $300\mathrm{.}0$ g of potassium chlorate generated $83\mathrm{.}4$ g of oxygen gas and $129\mathrm{.}5$ g of potassium chloride. what mass of potassium chlorate remains unreacted? you do not need to know nomenclature or what a mole is to solve this