题目

下列依据热化学方程式得出的结论正确的是 A.已知2H2(g)＋O2(g)===2H2O(g) ΔH＝－483.6 kJ·mol－1，则氢气的燃烧热为241.8 kJ·mol－1 B.已知NaOH(aq)＋HCl(aq)===NaCl(aq)＋H2O(l) ΔH＝－57.3 kJ·mol－1，则含40.0g NaOH的稀溶液与稀醋酸完全中和，放出的热量小于57.3 kJ C.已知2C(s)＋2O2(g)===2CO2(g) ΔH＝a，2C(s)＋O2(g)===2CO(g) ΔH＝b，则a＞b D.已知CH4(g)＋H2O(g) === CO(g)＋3 H2(g)  ΔH=+206.1 kJ·mol–1，反应过程中使用催化剂，ΔH减小—      do you watch TV every day? — For about half an hour.A．How muchB．How oftenC．How longD．How many