Question

Exactly 3.0 g of carbon was burned to ${CO}_2$ in copper calorimeter. The mass of calorimeter is 1.5kg and the mass of water in calorimeter is 2kg. The initial temperature was ${20}^{o}C$ and the final temperature was ${31.3}^{o}C$. If specific heat of copper is $0.0826cal/g-K$, the heat value to closest integer of carbon in kcal/g is

Answer 1

The quantity of heat transferred
$q=m_{water}\times S_{water}\times \Delta T_{water}+m_{copper}\times S_{copper}\times \Delta T_{copper}$
$q=2000\times 1\times 11.3+1500\times 0.0826\times 11.3$
$q=22600+1400=24000cal=24kcal$
This heat is for 3 g of carbon.
For 1 g of carbon, the heat transferred will be $\frac{24kcal}{3g}=8kcal/g$.