If we burn 3 moles of carbon in air (as per the equation), what mass (in grams) of carbon dioxide will be produced? What volume will this gas occupy at standard temperature and pressure?

So firstly, we assume that the oxygen is in excess (i.e. the amount of oxygen reacting won't limit the amount of carbon that can react), so we know that exactly 3 moles of carbon will be burnt. Then, from the equation we can see that for every one mole of carbon burnt, one mole of carbon dioxide is going to be produced. Therefore, if we know that we are producing 3 moles of CO2, we can work out the mass using the formula mass = moles*RFM.For the next part of the question, how much volume will this occupy, we can answer using our knowledge of gases. At standard temperature and pressure, one mole of any gas occupies 22.4 dm^3 of space, and so 3 moles of gas will have triple this volume, or 67.2 dm^3.