Question

Calculate the DH°rxn for the decomposition of calcium carbonate to calcium oxide and carbon dioxide. DH°f means delta or change of heat of formation DH°f [CaCO3(s)] = –1206.9 kJ/mol; DH°f [CaO(s)] = –635.1 kJ/mol; DH°f [CO2(g)] = –393.5 kJ/mol CaCO3(s) --> CaO(s) + CO2(g)

Answer 1

Answer: +178.3 kJ

Step-by-step explanation:

The chemical equation follows:

`CaCO_3(s)\rightarrow CaO(s)+CO_2(g)`

The equation for the enthalpy change of the above reaction is:

`\Delta H^o_(rxn)=[(1* \Delta H^o_f_((CaO(s))))+(1* \Delta H^0f_(CO_2)]-[(1* \Delta H^o_f_((CaCO_3(s))))]`

We are given:

`\Delta H^o_f_((CaO(s)))=-635.1kJ/mol\\\Delta H^o_f_((CaCO_3(s)))=-1206.9kJ/mol\\\Delta H^o_f_((CO_2(g)))=-393.5kJ/mol\\\Delta H^o_(rxn)=?`

Putting values in above equation, we get:

`\Delta H^o_(rxn)=[(1* (-635.1))+(1* (-393.5))]-[(1* (-1206.9))]`

The DH°rxn for the decomposition of calcium carbonate to calcium oxide and carbon dioxide is +178.3 kJ