Question

$0.3\, g$ of ethane undergoes combustion at $27^{\circ} C$ in a bomb calorimeter The temperature of calorimeter system (including the water) is found to rise by $05^{\circ} C$ The heat evolved during combustion of ethane at constant pressure is ___$kJ \, mol ^{-1}$ (Nearest integer) [Given : The heat capacity of the calorimeter system is $20 \, kJ\, K ^{-1}, R =83 \, JK ^{-1}\, mol ^{-1}$ Assume ideal gas behaviour Atomic mass of $C$ and $H$ are 12 and $1\, g\, mol ^{-1}$ respectively]

Answer 1

The correct answer is 1006.
(Bomb calorimeter → const volume
Heat released
By combustion of 1 mole
C2​H6​(ΔU)=−0.320×0.5​×30=−1000kJ
C2​H6​(g)+7/2O2​(g)→2CO2​(g)+3H2​O(l)
Δng=2−(2+7/2)=−(7/2)
ΔH=ΔU+ΔnRT
=−1000−7/2×8.3×300kJ
=−1000−6.225
=−1006kJ
So heat released =1006kJmol−1