Answer:-
g of carbon dioxide.
Solution:- The balanced equation for the combustion of methane is:
![CH_4+2O_2\rightarrow CO_2+2H_2O](https://tex.z-dn.net/?f=CH_4%2B2O_2%5Crightarrow%20CO_2%2B2H_2O)
There is 1:1 mol ratio between methane and carbon dioxide. Grams of methane are converted to moles and then using mol ratio we get the moles of carbon dioxide that could further be converted to grams. The calculations are shown as:
![6.40*10^-^3gCH_4(\frac{1molCH_4}{16gCH_4})(\frac{1molCO_2}{1molCH_4})(\frac{44gCO_2}{1molCO_2})](https://tex.z-dn.net/?f=6.40%2A10%5E-%5E3gCH_4%28%5Cfrac%7B1molCH_4%7D%7B16gCH_4%7D%29%28%5Cfrac%7B1molCO_2%7D%7B1molCH_4%7D%29%28%5Cfrac%7B44gCO_2%7D%7B1molCO_2%7D%29)
= ![1.76*10^-^2gCO_2](https://tex.z-dn.net/?f=1.76%2A10%5E-%5E2gCO_2)
So, complete combustion of given amount of methane gives
.
If the burning of magnesium to form magnesium oxide is incomplete, there will still br some elemental magnesium available to be burned (ie combined with oxygen) and so there will be a measureable amount of mass of magnesium left. Also, the amount of oxygen required to combine with the outstanding mass of magnesium could also be determined.