What volume of oxygen gas is released at STP if 10.0g of potassium chlorate is decomposed? The molar mass of KCIO_3KCIO3 is 122.55 g/mol?

1 Answer
Sep 7, 2016

KClO_3(s) + Delta rarr KCl(s) + 3/2O_2(g)

Approx. 3L of dioxygen gas will be evolved.

Explanation:

We assume that the reaction as written proceeds quantitatively.

Moles of KClO_3(s) = (10.0*g)/(122.55*g*mol^-1) = 0.0816*mol

And thus 3/2xx0.0816*mol dioxygen are produced, i.e. 0.122*mol.

At "STP", an Ideal Gas occupies a volume of 22.4*L*mol^-1.

And thus, volume of gas produced = 22.4*L*mol^-1xx0.0816*mol~=3L

Note that this reaction would not work well without catalysis, typically MnO_2.