The mole

10.0 cm³ of 1.00 mol/dm³ aqueous hydrogen peroxide, $H_2O_2$, decomposes according to the equation:

$2H_2O_2(aq) \rightarrow 2H_2O(l) + O_2(g)$.

The volume of oxygen collected at room temperature and pressure is 120 cm³.

What is the percentage yield of oxygen?

(1 mol of gas occupies 24 000 cm³ at room temperature and pressure.)