00:01
In the question, we are given with the enthalpy of combustion of c7h8.
00:07
Okay? so the enthalpy of combustion, that means del hc is given as minus 3910 .3 kilojoules mole in years.
00:32
Okay? and this is given for c7h8.
00:40
And we are asked to calculate the energy of combustion.
00:49
So we know what energy of combustion is equal to magnitude of enthalpy of combustion.
01:10
That means deluxe.
01:14
Or what we can get? we can get that energy of combustion is equal to 3910.
01:29
3 kilojoules more inverse.
01:33
Hence this will be the correct answer.
02:00
Now coming to b, in b we are given that the enthalpy of formation for co2 is given as minus 393 .3 .5 kilojoule inverse.
02:29
Then we are given with the enthalpyte of formation for water that is minus 285 .8 kilojoule more in there.
02:47
Next we are given with the enthalpy of formation of o2 and that is given as 0.
02:57
Why it is 0 because pure and stable form of element has the enthalpy of formation is 0.
03:07
Okay? so we can write the general equation here what? when c7h8 will or it reacts with o2, it gives rise to co2 plus h2...