题目内容

【题目】听下面一段对话,完成五道小题,每小题填写一个这段对话你将听两遍。

【答案】

(1) welcome speech

(2) 9:30

(3) second

(4) science labs

(5) workshops

【解析】听力原文:

Welcome to Mountford school. Thank you for choosing our school and for joining the happy Mountford family which has been educating boys since 1916. We are so happy that you've taken time off to be with us today. It is with great pleasure that we have prepared some events that we hope will please you. At 9:00 a.m., our headmaster will give a welcome speech. This will be in the school hall. Please be seated by 8:45 a.m.. Following the speech is the guided tour of the exhibition at 9:30. Here, you can see the proud history of our school, and our achievements in the field of education. The exhibition is laid out in the classrooms on the second floor. Then the guided tour of science labs at 10:20 a.m., here you can see the subjects that new students will be studying. You will also notice that our labs have excellent equipment. At 11:00 a.m., you will be taken on the tour to practical areas. This covers our technical workshops, music and other areas of our school life. At Mountford, we believe in all round development of our students. Lunch will be at 12:00. It has been specially prepared for our guests. All our teachers and student leaders will be present to answer any questions that you have in your minds. We are so happy that you could be with us today.

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【题目】雯雯在自学碳酸钠性质时,查到了以下资料:

CO2+Na2CO3+H2O===2NaHCO3,CO2通入饱和碳酸钠溶液会产生白色沉淀,CO2不溶于饱和碳酸氢钠溶液。

碳酸钠、碳酸氢钠在不同温度下的溶解度如表:

0

10

20

30

Na2CO3

7.1

12.2

21.8

39.7

NaHCO3

6.9

8.1

9.6

11.1

【进行实验1】验证CO2通入饱和碳酸钠溶液会产生白色沉淀

配制碳酸钠溶液:取100 g 20 的水,加入35 g碳酸钠固体,搅拌后,静置,取上层清液。

利用装置一进行实验,连续5分钟向新制得的碳酸钠溶液中通入CO2

【发现问题】实验中,始终没有看到沉淀现象,原因是什么呢?雯雯进行了以下实验探究。

【进行实验2】

实验操作

实验现象

取100 g 20 的水,加入35 g碳酸钠固体,搅拌后,静置,取上层清液

利用装置二进行实验,连续5分钟向新制得的碳酸钠溶液中通入CO2

没有出现白色沉淀

(1)在0 ~30 ,Na2CO3和NaHCO3的溶解度受温度变化影响较大的是

(2)大理石与稀盐酸反应的化学方程式为

(3)装置二中饱和碳酸氢钠溶液的作用是

【进行实验3】

实验操作

实验现象

取100 g热开水,加入35 g碳酸钠固体,完全溶解,再降温至20 ,取上层清液

利用装置一和装置二分别进行实验,连续3分钟向新制得的碳酸钠溶液中通入CO2

装置一和装置二中的碳酸钠溶液中均出现白色沉淀

(4)雯雯在最初的实验中没有看到沉淀现象的原因是

(5)CO2通入饱和碳酸钠溶液会产生白色沉淀的原因是

(6)请你依据题中信息,写出一种能够区分碳酸钠和碳酸氢钠固体的实验方案

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