题目

The chairman told the speaker that she _____ to speak a little louder so as to make herself _____. A. was expected; heard  B. had expected; hear C. had hoped; hear        D. was hoped; heard 答案：A17．下列热化学方程式中，正确的是（　　）A．甲烷的燃烧热△H=-890.3kJ/mol，则甲烷燃烧的热化学方程式可表示为：CH4（g）+2O2（g）═CO2（g）+2H2O（g）△H=-890.3 kJ/molB．一定条件下，将0.5 mol N2和1.5 molH2置于密闭容器中充分反应生成NH3放热19.3kJ，其热化学方程式为：N2（g）+3H2（g）?2NH3（g）△H=-38.6 kJ/molC．在101kPa时，2gH2完全燃烧生成液态水，放出285.8 kJ热量，氢气燃烧的热化学方程式表示为：2H2（g）+O2（g）═2H2O（l）△H=-571.6 kJ/molD．HCl和NaOH反应的中和热△H=-57.3 kJ/mol，则H2SO4和Ba（OH）2反应的反应热△H=2×（-57.3）kJ/mol