Can someone show his way of calculation for this Question, plz
OK right, here goes:
i) Moles of butane: 0.01/24=0.000417
From the equation, 1 mole of butane reacts with 6.5 moles of oxygen
Therefore, 0.000417*6.5=0.00271
So volume of oxygen reacted: 0.00271*24*1000=65cm
3 Therefore, volume of oxygen left: 100-65=
35cm3ii) From the equation, 1 mole of butane gives 4 moles of carbon dioxide
Therefore, 0.000417*4=0.00167
So volume of carbon dioxide formed: 0.00167*24*1000=
40cm3That was the technical way of doing it. Here is a simply way, but only applies if calculations involve gases only:
Consider this formula:
Volume of gas (in dm3)
Moles of gas = --------------------------
24
Because we know one mole of gas occupies 24dm
3 at r.t.p., therefore we can go about it this way:
i) From the equation, 1 mole of butane reacts with 6.5 moles of oxygen
So, 10cm
3 of butane reacts with 10*6.5=65cm
3 of oxygen
Therefore, volume of oxygen left: 100-65=
35cm3ii) From the equation, 1 mole of butane gives 4 moles of carbon dioxide
So 10cm
3 of butane gives 10*4=
40cm3 of carbon dioxide
However, the way I've gone about it using ratios can only be applied to gas volumes calculations, as explained above. For a lot of the others, you'll still need to apply the formula:
Mass
Moles = ------
Mr
If you still don't get it, let me know!