Question

化学热量计算已知下列各反应的反应热：Ca(s) + C(s,石墨) + 3/2 O2(g) = CaCO3 (s) △H

Answer 1

选A

CaCO3 (s) = Ca(s) + C(s,石墨) + 3/2 O2(g) △H1 = 1206.8 kJ/mol

Ca(s) + 1/2 O2(g) = CaO(s) △H2 = - 635.1 kJ/mol

C(s,石墨) + O2(g) = CO2 (g) △H3 = - 393.5 kJ/mol

以上三个反应相加,就可以得到CaCO3(s) = CaO(s) + CO2(g)

因此,反应热也是相加的关系△H =△H1+△H2+△H3=178.2 kJ/mol