Question

Calculate the mass of potassium chlorate required to liberate 6.72 dm^3 of oxygen at STP molar mass of potassium chlorate is 122.5g/mol

Answer 1

Now the molar volume at STP for an ideal gas is 22.4 dm3/mol (assuming O behaves ideally we shall take this number). Intuitively speaking one mol of ideal gas occupies 22.4 dm3 volume. Hence if u have 6.72 dm3 of ideal gas u have 0.3 mol of that gas (6.72/22.4).