问题 写作题

书面表达。

     初中生活即将结束,我们有很多不能忘记的美好记忆。与同学之间的友好交往,与老师之间的坦

诚沟通。与家长之间的倾心交流……已成为我们生活中的重要内容。请以(My Past Beautiful Life)为题,写一件你与同学(或朋友、老师、家长)等曾经经历过的美好事情,以表达对他们的感激或怀念之情。

     要求:1. 书写规范,层次清楚,真情实意。 

               2. 文章中不得使用你及你的朋友、同学、老师、家长的真实姓名和校名。 

               3. 词数不少于80词。

     部分参考词汇: an unforgotten time (一段难忘时光) meaningful(有意义的) thankful(感激的)

moved(感动的)

                                               My Past Beautiful Life

     _____________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

答案

                                                             My Past Beautiful Life

      Our life in middle school will come to an end soon. It was an unforgotten time. I will never forget you

an outgoing boy. There is always smile on your face and everybody likes to make friends with you. We used

to play basketball on the playground. It was very meaningful for us to play basketball. Sometimes we went to

the park and had a good time there. I always laughed a lot when I was with you. So I was thankful and moved. At this very moment I'm saying goodbye to you, I just want to give you my best wishes: I hope you are happy and healthy forever. I hope you are successful in the future.

(答案不唯一)

判断题
实验题

由正丁醇(用nC4H9OH表示)制备正溴丁烷(沸点:101.6 ℃)的反应如下:nC4H9OH+NaBr+H2SO4―→nC4H9Br+NaHSO4+H2O

副反应:nC4H9OHCH3CH2CHCH2↑+H2O

2nC4H9OH(nC4H9)2O+H2O

3H2SO4(浓)+2NaBr(固)=2NaHSO4+Br2↑+SO2↑+2H2O

已知反应物及其用量:固体NaBr 0.24 mol,nC4H9OH 0.20 mol,浓H2SO4 29 mL,H2O 20 mL。

制备过程经历如下五个步骤,试回答下列问题:

(1)投料:在圆底烧瓶中加入20 mL水,再慢慢加入29 mL浓硫酸,混合均匀并冷却至室温后,再依次加入0.20 mol正丁醇(约18 mL)和0.24 mol溴化钠,充分振荡后加入几粒沸石。

①冷却至室温后再加正丁醇和溴化钠的目的是________。

A.减少HBr的挥发

B.防止正丁醇的挥发

C.防止溴化钠被氧化

D.防止温度过高导致炭化结焦②本反应中硫酸与溴化钠作用生成氢溴酸,氢溴酸与正丁醇作用发生取代反应生成正溴丁烷。硫酸的用量和浓度过大都对本制备不利的主要原因是

_____________________________________________________。

(2)加热回流:反应装置选择Ⅱ而不选择Ⅰ的原因是_________________。在反应装置中冷凝水应该从________(填“A”或“B”)端进水。

(3)分离粗产物:反应结束待反应液冷却后,用直形冷凝管换下球形冷凝管,将其变为蒸馏装置进行蒸馏,得到的粗产物中除主产品外,还含下列选项中的________。

①C4H9OH ②SO2 ③(C4H9)2O ④Br2 ⑤NaHSO4   ⑥H2O ⑦H2SO4

(4)洗涤粗产物:将馏出液移至分液漏斗中,加入等体积的水洗涤后,分液得有机层。如果不能判断哪层是有机层,可以用_______________方法来判断。对有机层,进行洗涤除杂、除水后可得到粗产品。

(5)收集产物:将干燥好的产物移至小蒸馏瓶中,加热蒸馏,收集99~103 ℃的馏分。要证明最终产物是nC4H9Br,方法是_____________________________

___________________________________________。