In the equation #2KClO_3 -> 2KCl + 3O_2#, if 5.0 g of #KClO_3# is decomposed, what volume of #O_2# is produced at STP?
Find the relative mass of the molecule
Divide the total mass of the substance by its relative mass to find the number of moles of the substance.
There are two moles of
One mole of an ideal gas at STP (standard temperature and pressure) occupies 22.4L.
which should be your final answer, depending on how you've rounded.