题目

现有一定量含有Na2O杂质的Na2O2试样，用如图的实验装置测定Na2O2试样的纯度。(可供选用的反应物只有CaCO3固体、6mol·L-1盐酸、6mol·L-1硫酸和蒸馏水) 回答下列问题： （1） 装置A中漏斗液体试剂选用，理由是。 （2） 装置B的作用是。装置C的作用是。装置E中碱石灰的作用是。 （3） 装置D中发生反应的化学方程式是。 （4） 若开始时测得样品的质量为2.0g，反应结束后测得气体体积为224mL(密度为 g/L)，则Na2O2试样的纯度为。阅读下列短文，根据短文中的信息完成文后表格。（每空一词）7 NovemberDear Dairy,Today is our Open Day. Our parents come and visit our school on this day.Our school looks nice and big. The playground is very big and our classrooms are clean and bright. We also have an art room, a music room, a biology room and a small hall.The Open Day starts at 9 a.m. in the playground. Everyone watches the students play different sports. Next we go to the art room to enjoy all the students’ pictures at 10 a.m. At 11 o’clock we all go to the school hall for a short meeting, and then we have lunch. After lunch, we have a little rest for half an hour in the hall. At 2p.m.we have a look at all the students’ work in the biology classroom. Finally we go to the music room and listen to some students play music at 4p.m.Everyone has a good time at school on this day.Open DayDate:     76 7thTime    77    Place9a.m.Watch the students      78   sportsPlayground10a.m.     79  students’ picturesArt room11a.m.     80  School hallAfter lunchHave a rest for thirty   81  Hall2p.m.    82   at students’ work   83    classroom4p.m.Listen to    84  Music roomEveryone has   85 on this Open Day.