3.2.1 Energetics - Calorimetry
Students should:
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Calculation of enthalpy changes
Change in energy = mass x specific heat capacity x change in temperature 
q = m x c x ΔT
Enthalpy changes (ΔH) are related to the number of mols in the reaction...if all the coefficients are doubled, then the value of ΔH will be doubled.
When a reaction is carried out in aqueous solution, the water will gain or lose heat from (or to) the reactants. Therefore, the change in energy, and so the ΔH value, can be calculated from q = m x c x ΔT where m is the mass of water present (kilograms), and c = 4.18 kJ Kg-1 K-1. The ΔH value can then be calculated back to find the molar enthalpy change for the reaction.
Experimental
A known mass of solution should be placed in a container, as insulated as possible, to prevent as much heat as possible from escaping. The temperature is measured continuously, the value used in the equation is the maximum change in temperature from the initial reading.
The result will be a change in temperature. This can be converted into a change in heat (or energy) by using the above equation q = m x c x ΔT.
Δ-H may then be calculated for the amount of reactants present, and then this can be used to calculate for a given number of mols.
