What volume of oxygen gas is released at STP if 10.0g of potassium chlorate is decomposed? The molar mass of #KCIO_3# is 122.55 g/mol?

1 Answer
Sep 7, 2016

Answer:

#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#.