\(\Delta H = {(\Delta {H_{f}})_{CaO}} + {(\Delta H_{f})_{C{o_2}}} - (\Delta {H_{f}})CaC{O_3}\)
\(42 = - 152 - 94 - {(\Delta {H_{f}})_{CaC{O_3}}}\)
\( \Rightarrow \,{(\Delta {H_{f}})_{CaC{O_3}}} = - 246 - 42 = - 288\,kJ.\)
$ C(s)\,\, + \,\,{O_2}(g)\,\, \to \,\,C{O_2}\,(g)$ $\Delta H = \,\, - \,94\,\,kcal$
${H_2}\,(g)\,\, + \,\,\frac{1}{2}\,{O_2}\,(g)\,\, \to \,\,{H_2}O\,(g),$ $\Delta H\,\, = \,\, - \,68\,\,kcal$
${C_2}{H_5}OH\,(\ell )\,\, + \,\,3{O_2}\,(g)\,\, \to \,\,2C{O_2}\,(g)\,\, + \,\,3{H_2}O\,(\ell ),$$\Delta H\,\, = \,\,\, - \,327\,\,kcal$