Question

Calculate the heat of decomposition for this process at constant pressure and 25°C:CaCO3(s) CaO(s) + CO2(g)AHf of CaCO3 = -1207.6 kJ/molAHỆ of CaO = -634.9 kJ/molAHf of CO2 = -393.5 kJ/mol

Answer 1

1) Balance the chemical equation.

`CaCO_(3(s))\rightarrow CaO_((s))+CO_(2(g))`

2) List known values

ΔHf of CaCO3 = -1207.6 kJ/mol

ΔHf of CaO = -634.9 kJ/mol

ΔHf CO2 = -393.5 kJ/mol

3) Write the enthalpy change equation.

`\Delta Hº=\Sigma n\Delta Hºf(products)-\Sigma n\Delta Hºf(reactants)`

n= stoichiometric coefficients

4) Plug in the known values

`\Delta Hº=\lbrack(1*CaO)+(1*CO_2)-(1*CaCO_3)\rbrack`
`\Delta Hº=\lbrack(1*-635\text{ }kJ/mol)+(1*-393.5\text{ }kJ/mol)-(1*-1207.6\text{ }kJ/mol)\rbrack`
`\Delta Hº=+179.1\text{ }kJ/mol`

The

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