Question

How can I calculate the mass and volume of oxygen released when 29, 4 potassium chlorate discomposed to form potassium chloride and oxygen??

Answer 1

2 KClO3 ==> 2KCl + 3O2

mols KClO3 = g/molar mass = 29.4/122.5 = 0.24
Convert to mols O2 formed using the coefficients in the balanced equation.
mols O2 formed = 0.24 x (3 mols O2/2 mols KClO3) = 0.24 x 3/2 = 0.36
1. For mass, grams O2 = moles O2 x molar mass O2 = ?
2. You don't list the pressure or temperature for the volume but for volume @ STP, 0.24 mols O2 x 22.4 L O2/mol = ?
Post your work if you get stuck.