Prashant Pradhan YR 11
Chemistry HL – Enthalpy of combustion
Chemistry Lab report – Enthalpy of combustion
Aim: To see the trend in the combustion of the first five alkanols.
Introduction:
The standard enthalpy of combustion is the enthalpy change when one mole of a substance completely reacts with oxygen under standard thermodynamic conditions (although experimental values are usually obtained under different conditions and subsequently adjusted).
E.g. The standard enthalpy of combustion of ethane is the energy released when one mole of ethane is completely burned in excess oxygen under standard conditions. i.e. the energy change for the reaction:
C2H6 + 3.5 O2 → 2CO2 + 3H2O
By definition, combustion reactions are generally strongly exothermic and so enthalpies of combustion are generally strongly negative.
It is commonly denoted as or
Enthalpies of combustion are typically measured using bond calorimetry, and have units of energy (typically kJ); strictly speaking, the enthalpy change per mole of substance combusted is the standard molar enthalpy of combustion (which typically would have units of kJ mol−1).
