Why does burning wood leaves an ash that is only a small fraction of the mass of the original wood.?

Explanation:

Burning wood leaves an ash which is a small amount of original mass of wood because when we burn wood, large amount of wood is converted into carbon dioxide and water vapor. In complete combustion, there would be no ash remaining, because all the fuel have been consumed completely. When we sum up the mass of gasses released in burning and the ashes we get the original mass.

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.