Enthalpy change of neutralization

In the case of a strong acid and a strong base, not only the salt, but also the reactants are completely dissociated. The reaction is effectively that between hydroxonium and hydroxyl ions, and it will apply for any strong acid with any strong base. As a result, we find that the enthalpy change of neutralization is approximately constant for any such reaction, and equals -56.07 kJ/mol. 

II) The enthalpy change of neutralization (AH ) is the standard enthalpy change when one mol of water is made in the neutralization of an acid by a base. Values are ... 

The standard enthalpy change of neutralization is the enthalpy change that takes place when one mole of hydrogen ions is completely neutralized by an alkali under standard conditions. 

An example of the enthalpy change of neutralization is from the reaction between sodium hydroxide solution and hydrochloric acid. The reaction can be described by the following thermochemical equation ... 

Figure 5.12 A graph of temperature versus volume of acid for an investigation to determine the enthalpy change of neutralization for an acid... 

A simple method for determining the enthalpy change of neutralization involves mixing equal volumes of dilute solutions of a strong acid and a strong base of known concentration and measuring the temperature rise. A thick plastic cup fitted with a lid makes a cheap and effective calorimeter. 

BO.OOcm of I.Omoldm-3 hydrochloric acid was added to BO.OOcm of I.Omoldm- sodium hydroxide solution. The temperature rose by 6.8°C. Calculate the enthalpy change of neutralization for this reaction. Assume that the density of the solution is I.OOgcm" and the specific heat capacity of the solution is4.18Jg °C . ... 

Use your results to determine the enthalpy change of the neutralization reaction, in kj/mol of NaOH. Write the thermochemical equation for the neutralization reaction. 

The structure and energy of a series of ions generated from penta-cyclo[3.3.1.13,7.01 3.05 7]decane (7) has been explored by using HF, MP2 and DFT methods to estimate enthalpy changes of isodesmic disproportionation reactions and by considering the reorganization of frontier orbitals as a consequence of addition or removal of electrons from the neutral molecule.8 The dication (72+), which is considered to be Three-dimensionally homoaromatic , is stable relative to a localized structure with similar features but is highly unstable compared to the radical cation (7+i)- hi contrast, the dianion (72 ) is unstable relative to the radical anion (T) and shows no evidence of electron delocalization. 

The appearance potential of an ion in the mass spectrometer corresponds to the enthalpy change of the reaction in which the ion is formed from the parent neutral species. For example, for... 

The standard enthalpy change for the ionization of water is +55.83 kJ mol", which means that the reverse reaction, which occurs when acids are neutralized by bases, is exothermic, i.e. ArH = —55.83 kJ mol-1. The corresponding change in standard Gibbs energy is —79.9 kJ mol - . The reaction ... 

As a result of the ability to make these extended combinations, silicates usually exist as large polymeric structures, with metal ions of various amounts and types incorporated to maintain electrical neutrality. The energy or enthalpy change leading to the formation of these complex silicates involves the making (or breaking) of silicate linkages. 

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