 Okay, in this problem what we are looking at is calculation of average molar composition here. Actually molar composition given mass composition. Typically we should remember that whenever gas composition is given it is usually either mole percent or volume percent. In this case specifically we have here mass percent. So we are trying to convert it into traditional molar percentage values composition. So the way we do it is, if we were to take 100 grams of this sample and 16 percent would be oxygen, right? So which means 16 grams would be oxygen and CO would be 4 grams similarly and CO2 would be 17 grams, right? And then nitrogen would be 63 grams, this we are familiar with. Now moles, if we want to calculate molar composition, molar composition is mass divided by molecular weight will give you the number of moles, so we are familiar with that. So that this divided by 32 will give us the oxygen and this divided by 28, I have given here the molecular weights listed. So this 4 grams, oops, yeah this is the total, I am sorry here, okay 100 grams is the total mass, 16 grams is O2 here, 16 divided by 32 will give us the moles of oxygen, 4 divided by 28 will give us the moles of carbon monoxide CO2, similarly divided by 44 and here nitrogen divided by 28, that will give us the number of moles of each of these compound. Okay, we have the composition now. This is the number of gram moles oxygen, number of gram moles of CO and number of grams moles of CO2 and number of gram moles of nitrogen. So now we have the number of moles, so it is easy now to calculate the molecular or molar percent. So the total number of moles that we have here are now 3.278 gram moles. The total mixture consists of now 3.278 gram moles, assuming that we start with 100 gram moles. So this mixture out of this 3.278 gram moles, the proportion of oxygen is 0.5 moles. So if we divide this by the total, which is 3.28, 3.278, let me write it clearly here, 0.278, similarly 3.278 divided by 3.278, you will get the mole fractions, okay. So these are the mole fractions of each of these gases, 0.152. The way we got it is 0.5 divided by 3.278, that's 0.152, 0.043 in this case, 0.117 and 0.686. When you add up these things, you will get one. So now this is the mole fractions, so when you add up all the fractions, some should be one. If we were to calculate the percentage of the composition, all we have to do is multiply because in one, there is 0.15, in 100, it will be 100 times more. So 15.2 percent would be your oxygen here and CO will be 0.043 times 100, which will be 4.3 percent and CO2 is 11.7 percent, rest of it is nitrogen, nitrogen is 68.6 percent. So the main thing that we need to look at here is this is the mass percent and this is the molar percent or volumetric percent. They're almost in the same range, however, there is difference here. Some of them have gone down and some of them have gone up. This is based on the molecular weight. So this is volumetric percent or mole percent. Gases are the same, the numbers will not change mole percent versus volumetric percent. That's it.