How much potassium chlorate should be heated to produce 2.24 L of oxygen at NTP?

1 mole of potassium chlorate produces 3 moles of oxygen gas when heated, or 1 mole of potassium chlorate produces 1.344 L of oxygen gas at NTP. To produce 2.24 L of oxygen gas, you would need about 1.67 moles of potassium chlorate.