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).
= 1211 kJ mol-1. Therefore the molar heat of combustion of ethanol is 1211 kJ mol-1 (The molar enthalpy of combustion of ethanol is 1211 kJ mol-1). (Note that the enthalpy change for the reaction is negative because the reaction is exothermic, so the enthalpy change for the reaction is -1211 kJ mol-1, ÎH = - 1211 kJ mol-1)