题目

I’m Yangyang. Look! This is No. 2 High School. My friend Dongdong is in this school. Dongdong has long hair, a long neck, a small mouth and big eyes. He is thirteen. He is in Class Two, Grade Seven. He is a good student. He has two good friends in his school. They are Jim and Jack. They are English boys. They are twins(双胞胎). They are fourteen. They have small noses, small eyes, but they are very tall. Jim, Jack and Dongdong are in the same class. Mr. White is their (他们的) English teacher. 根据短文内容，判断正(T)误(F)。【1】Dongdong has big eyes and short hair.【2】（18分）张明同学对硫酸及其盐的某些性质中进行了如下实验探究。[实验一]探究浓硫酸的氧化性　　将实验室常用的药品放入如右图所示的实验装置后，加热装置甲。（夹持和加热装置省略）（1）该装置设计上存在明显缺陷，其缺陷是        _________________________________           ___。（2）装置甲中反应的化学方程式是___________                           ___。（3）装置乙中的试剂是_____________________________________________________。[实验二]探究某硫酸亚铁盐固体是否变质（4）请你帮助张明同学完成如下实验方案： 实验操作 预期现象和结论 [实验三]用KHSO4制取H2O2并测其质量分数查阅资料得知：工业上用电解KHSO4饱和溶液制取H2O2，示意图如下：张明用此法制取一定浓度的H2O2，并进行下列实验测定H2O2的质量分数：（离子方程式：2MnO4―＋5H2O2＋6H＋＝2Mn2＋＋8H2O＋5O2↑）①取5.00 mL H2O2溶液（密度为1.00 g/mL）置于锥形瓶中加水稀释，再加稀硫酸酸化；②用0.1000 mol/L KMnO4溶液滴定；③用同样方法滴定，三次消耗KMnO4溶液的体积分别为20.00mL、19.98 mL、20.02 mL。请回答：（5）电解饱和KHSO4溶液时，阳极的电极反应式为____________________________。（6）操作②中，滴入第一滴KMnO4溶液，溶液紫红色消失很慢，随着滴定过程中Mn2＋的增多，溶液紫红色消失速率加快。Mn2＋的作用是_____________              ___。（7）原H2O2溶液中溶质的质量分数是__________                  _____    ____。