Enthalpy of neutralization
 |
This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2007) |
The enthalpy of neutralization (ΔHn) is the change in enthalpy that occurs when an acid and base undergo a neutralization reaction to form water and a salt. It is a special case of the enthalpy of reaction.
When a reaction is carried out under standard conditions at the temperature of 297 K and 1 atm of pressure and one mole of water is formed it is called the standard enthalpy of neutralization (ΔHno).
The heat (Q) released during a reaction is
- Q = m cp ΔT
where m is the mass of the solution, cp is the specific heat capacity of the solution, and ∆T is the temperature change observed during the reaction. From this, the standard enthalpy change (∆H) is obtained by division with the amount of substance (in moles) involved.
- ∆H = - Q/n
The standard enthalpy change of neutralization for a strong acid and base is -57.3 kJ/mol.
The standard enthalpy of neutralization for mineral acids is slightly less exothermic than that of organic acids, because of the partially ionising property of weak acids. The bond between the proton and its conjugate base requires energy to be broken, hence the lower measured value enthalpy change.
 |
This chemistry-related article is a stub. You can help Wikipedia by expanding it. |
