问题 句型转换

根据所给提示,完成句子。每空一词,含缩略词。

1. She does her homework every day. (变否定句)

    She                         her homework every day.

2. They knew little about this matter. (变反意疑问句)

    They knew little about this matter,                          ?

3. The police took the sick boy to hospital yesterday. (改为被动语态)

    The sick boy                           to hospital by the police yesterday.

4. He decided to walk there because the bus broke down on the way. (同义句)

    He              up his              to walk there because the bus stopped to work on the way.

5. It's said that he borrowed this book two days ago. (同义句)

    People say that he                         this book for two days.

答案

1. doesn't do  2. did they  3. was taken  4. made mind  5. has kept

实验题

氯化苄(C6H5CH2Cl)是一种重要的有机化工原料,广泛应用于医药、染料、助香料等有机化工产品的制备。氯化苄为无色液体,具有强烈的催泪作用,沸点为179.4℃,不溶于水,可混溶于乙醇、氯仿等多数有机溶剂。工业上采用甲苯与干燥氯气在光照条件下反应合成氯化苄。为探索不同光强条件对合成产率的影响,需要对不同光强条件下的粗产品进行纯度检测。每一组检测按照如下步骤进行:

①称取0. 255 g样品。

②将样品与25 mL 4 mol/L NaOH水溶液在100 mL圆底烧瓶中混合,水浴加热1小时后停止加热(在如图所示装置中进行反应,发生的反应为C6H5CH2Cl+NaOH→C6H5CH2OH+NaCl)。

③在烧瓶中加入50 mL 20% HNO3,混合均匀。

④将烧瓶中溶液全部转移到100 mL容量瓶中,加水定容。

⑤从容量瓶中取出25. 00 mL溶液于锥形瓶中,加入6.25 mL 0.100 mol/L AgNO3溶液,振荡混合均匀。

⑥在锥形瓶中滴入几滴NH4Fe(SO4)2溶液作为指示剂,用0.0250 mol/L NH4SCN溶液滴定剩余的AgNO3

⑦重复⑤⑥步骤三次,消耗0. 025 0 mol/L NH4SCN溶液的平均值为6.75 mL。

(已知:NH4SCN+AgNO3=AgSCN↓+NH4NO3)

根据以上实验信息回答下列相关问题:

(1)上图中烧瓶上的冷凝管所起的作用是____________。

(2)步骤③所加硝酸的目的是__________。

(3)在步骤⑤操作中,可用_________(填仪器名称)取6.25 mL 0.100 0 mol/L 的AgNO3溶液。

(4)在步骤⑥操作中,判断达到滴定终点的现象是_____________。

多项选择题