question_answer

The heat evolved on combustion of 1 gm starch \[{{\left( {{C}_{6}}{{H}_{10}}{{O}_{5}} \right)}_{n}}\]  into \[C{{O}_{2}}\]  and \[{{H}_{2}}O\,\left( \ell  \right)\]  is \[17.49\,\,kJ\,\,g{{m}^{-1}}.\]  Compute the enthalpy of formation of 1 gm starch. Given \[\Delta {{H}_{f}}\,\,of\,\,{{H}_{2}}O\,\,\left( \ell  \right)\,\,=\,\,-\,285.85\,\,kJ\,\,mo{{l}^{-1}},\] \[\Delta {{H}_{f}}\,\,of\,\,C{{O}_{2}}\,\,=\,\,-293.7\,\,kJ\,\,mol{{e}^{-1}}\]

Answer:

-5.91