00:01
Hello students in this question we have a bomb calorimeter and this reaction is happening at constant volume so when the volume is constant the change in volume is zero and here pressure is not constant also they are telling that the heat absorbed by the system at constant volume is plus 15 joules so to now find out the correct option we have to consider a few formulae so here we know that work done w is equal to p delta v and since delta v is zero w is also zero now we know at constant volume the internal energy that is delta e of reaction is equal to the heat absorb plus work done so we know that work done is zero so there therefore, the internal energy that is delta e of reaction is equal to heat absorbed that is qv which is equal to plus 15 joules.
01:19
So from here we got one relation and we know work done is zero.
01:25
So therefore if work done is zero, delta e of reaction is equal to qv and therefore this is another equation we got now we have constant volume so therefore talking about the enthalpy change we have at constant volume delta h that is the enthalpy change is to delta e of reaction that is internal energy plus v delta p so here we know that internal energy is plus 15 plus we have v delta p so there is some volume and there is some variable pressure so delta h cannot be just equal to plus 15 jules because of the reason that there will be something added to it so this we got also delta h cannot be equal to minus 15 as well so we have all these relations and if we consider the options so let us see the options now.
02:45
So we have option number a given to us that delta e of reaction is minus 15 joules which is wrong because we know that delta ef reaction is plus 15 joules.
03:01
So a is not the answer.
03:04
Now coming for the b we have q equal to w.
03:07
So no, q we have as plus 15 joules and w is 0.
03:12
So b is also not the correct option.
03:14
Now coming to c we have work done equals to 0...