问题 填空题

(15分)某同学发现在灼热的煤炭上洒少量水,煤炉中会产生淡蓝色火焰,煤炭燃烧更旺,因此该同学得出结论“煤炭燃烧时加少量水,可使煤炭燃烧放出更多的热量。”(已知煤炭的燃烧热为-393.15 kJ/mol,氢气的燃烧热为-242 kJ/mol,一氧化碳的燃烧热为-283 kJ/mol)

(1)写出该同学看到燃烧现象所涉及到的所有热化学反应方程式;

                                                                    

                                                                       

                                                                     

                                                                                                                              

(2)你认为该同学的结论是否正确,请简要说明理由。                             

答案

(1)C(s) + O2 (g) = CO2(g)            △H = -393.15 kJ/mol  

H2 (g) + 1/2 O2 (g) = H2O (l)            △H = -242 kJ/mol

CO(g) + 1/2 O2 (g) = CO2(g)            △H = -283 kJ/mol

C(g) + H2O (l) = CO(g) + H2 (g)        △H =" +131.85" kJ/mol

(2)不正确。因为根据盖斯定律,反应过程中的热效应与途径无关,只与反应物和生成物的能量差有关。

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