题目

 A. (13 分)H2O2 在实验、医疗、化工方面有广泛的应用。 （1）H2O2 中 O 的化合价为          。 （2）实验室中用双氧水（H2O2 溶液）制取 O2 的化学方程式为                            。 （3）酸性高锰酸钾溶液可与双氧水中的 H2O2 反应，其化学方程式是： 5H2O2 + 2KMnO4 + 3H2SO4 = X + 2MnSO4 + 5O2↑ + 5H2O 已知：稀 MnSO4 溶液几乎无色 ①用双线桥法标出上述反应中电子转移的方向和数目。 ②X 的化学式是         ，KMnO4 的摩尔质量是      �Ⅲ.语法填空[20巧.哈尔滨六中高三二模]阅读下面材料，在空白处填人适当的内容a个单词）或括号内单词的正确形式。British families started going on holiday to the seaside around the middle of the 19th century.The14._______________ (invent) of the railways made this possible. The first holiday-makers 15. (be) quite rich and went for their health and education. The seaside was a place to cure people of illnesses. And doctors recommended bathing in the sea and drinking sea water. At that time ordinary working people had very little time off work. 16. _____________ ， in 1871， the government ntroduced four "Bank Holidays", that is, national holidays. This allowed people 17. _____________ (have) a day or two out now and then, 18. __________ gave them a taste for leisure at the seaside. At first, they went on day trips, taking advantage 19.___________ special trip tickets on the railways.By the 1880s, 20.______________(rise) incomes meant that many ordinary workers and their families could have a week's holi?day at the seaside. Rail fares were reduced and cheap hotels  21. _____ (build)  for them. Holidaymakers enjoy 22_____________(sit) on the beach, bathing in the sun and eating ice cream. Cheap entertainment was on offer and holiday-makers went to have fun. Today 23. ___________   English seaside remains popular with more than 18 million holidays taken there each year.