# In order to calculate the enthalpy change of Calcium Carbonate to Calcium Oxide, which is exceedingly hard to control and measure the energy change we must use Hess' law

Results

In order to calculate the enthalpy change of Calcium Carbonate to Calcium Oxide, which is exceedingly hard to control and measure the energy change we must use Hess’ law which states:-

“The total enthalpy change for a chemical reaction is

independent of the route by which the reaction takes lace,

provided initial and final conditions are the same”

So therefore on adding Hydrochloric acid, which reacts readily with both, Calcium Carbonate and Calcium Oxide they both form Calcium Chloride crating a enthalpy energy triangle.

ΔH3

CaCO (s)                                              CaO(s) + CO (g)

ΔH1                                                     ΔH2

CaCl (aq)

Therefore:-

ΔH1 - ΔH2 = ΔH3

But we cannot enter our results directly into Hess’ equation, we must convert them into Enthalpy energies. With the enthalpy energy values for Calcium Carbonate and Calcium Oxide only then can we calculate the enthalpy change for Calcium Carbonate and Calcium Oxide.

Enthalpy Calculations

There are a few equations I must use to obtain my final answer firstly I must calculate the energy transferred in the reaction using the following equation:-

Equation 1

Mass of liquid(g) x specific heat capacity of

aqueous solution(Jg K ) x temperature rise(°C) = Energy Transferred (J)

OR

ΔH = -M x Cp x ΔT

But this doesn’t calculate the energy transferred per mole, to do this I must use:-

Equation 2

= No. of Moles (mol)

Mass of Chemical used(g)  _

Molecular weight of Molecule

Lastly we must convert the energy transferred into moles to do this:-

Equation 3

1

No of Moles

...