hii answer isExplanation: Heat2KClO 3 Heat 2KCl+3O 2 The mole ratio for the reaction is 2:2:1 meaning, two MOLES of KClO 3 yields 2 moles of KCl and 3 moles of O 2 CALCULATE the moles of oxygen from the 6.72 dm 3 given1 dm 3 =1 liter 6.72 dm 3 =6.72 liters of oxygenUsing the ideal gas law, which states that 1 mole of an ideal gas occupies 22.4 liters by volume we can calculate the moles of oxygen as follows:If 22.4 liters = 1 moleThen 6.72 liters = 1 × 6.72/ 22.4 = 0.3 molesFrom the equation above we FOUND the mole ratio for the equation to be 2:2:1That means, for 0.3 moles of oxygen to be liberated, we will need 0.3 × 2 = 0.6 moles of KClO 3 USE the 0.6 moles of KClO₃ to find the mass requiredMoles = mass / molar mass Then,mass = molar mass × molesmolar mass of potassium chlorate is 122.5 g/mol (GIVEN) and moles is 0.6(calculated)Therefore mass of KClO 3 required = 122.5 g/mol x 0.6 moles = 73.5 gTherefore you need 73.5 g of potassium chlorate to liberate 6.72 dm 3 of oxygen.