Chemistry lab report
Aim- to determine then enthalpy of neutralization for
- HCl +NaOH
And state the trends in the enthalpy of neutralization for acids.
The enthalpy of neutralization is the heat produced when an acid and a mole react together to form one mole of water. Strong acids completely dissociate in water. Weak acids on the other hand partially dissociate in water. Thus a certain amount of the energy evolved, in reacting a weak acid with a base, is used up in ionizing the unionized molecules.
Hence the enthalpy of neutralization should be more for the stronger acids and lesser for the weak acids. Thus the enthalpy of neutralization will be more for hydrochloric acid and sulphuric acid, which are stronger acids and lesser for ethanoic acid, which is a weak acid.
The hydrogen ion from the acid and the hydroxide ion from the base react to form the water molecule. the general equation of the reaction would be-
H+ + OH- H2O
The energy released when the above reaction takes place is -57.3 KJ/mol. Hence the energy released when HCl and H2SO4 reacts with the base should be the same since they completely dissociate in water. It should be slightly lesser for ethanoic acid since some of the energy released should be used up to ionize the unionized molecules.