1. 1  an implement, such as a hammer, saw, or spade, that is used by hand. 2  a power-driven instrument; machine tool. ( 3 in combination): a toolkit.
The standard enthalpy of combustion is the enthalpy change when one mole of a reactant completely burns in excess oxygen under standard thermodynamic conditions (although experimental values are usually obtained under different conditions and subsequently adjusted).he standard enthalpy of combustion is the enthalpy change when one mole of a reactant completely burns in excess oxygen under standard thermodynamic conditions (although experimental values are usually obtained under different conditions and subsequently adjusted).
Example 2 Standard enthalpies of formation are: C2H5OH(l) -228, CO2 -394, and H2O(l) -286 kJ/mol. Calculate the enthalpy of the reaction, C2H5OH + 3 O2 Â® 2 CO2 + 3 H2O Solution. From the definition of the enthalpy of formation, we have the following equations and the energy changes of reactions.rite the enthalpies of formation below their formulas in the equation, we have: A handbook gives the enthalpy of formation of NH. 1  Calculate the enthalpy of the reaction CH4 + 2 O2 = CO2 + 2 H2O from the enthalpies of formation: CH4 -75 kJ/mol, CO2 -394, and H2O(l) -286 kJ/mol.