问题 填空题

小明走进实验室发现一瓶标明溶质质量分数为10%的无色溶液,旁边还摆放了分别盛有氢氧化钠、氯化钠、氢氧化钙和碳酸钠固体的试剂瓶,估计是哪位同学用这几种药品中的一种配制了这瓶溶液,但忘了标明成分,他进行了如下实验检验溶液的成分:

溶液

滴入无色酚酞
溶液变红
滴入过量稀盐酸
溶液逐渐褪色,无气泡产生

小明认为该溶液中的成分肯定不是氢氧化钙,理由是______;根据图中所示现象分析得出这瓶溶液应该是______.

答案

氢氧化钙是微溶于水的物质,不能得到10%的溶液,所以不能为氢氧化钙溶液,根据实验现象可以知道,加入了无色酚酞液后变红,说明溶液为碱性,但是加入稀盐酸后没有气体产生,所以结合题干中所给的物质可以判断该溶液为氢氧化钠溶液.

故答案为:氢氧化钙微溶于水、不可能配制出10%的溶液;氢氧化钠溶液.

完形填空

第二节(共5小题;每小题2分,满分10分)

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

_71_ One of the best things you can possibly do is to start you own club. It’s great fun especially if you are the sort of person who feels there’s never anything to do during the school holidays.

The first thing you need to come up with is an idea for your club. _72_ Pets, clothes, pop music or dancing groups, sports, making things? The list is endless.

Next you need some friends to be in your club with you. _73_ All you need is three or four other people who are interested in the same thing as you.

_74 You should all sit down somewhere together with lots of pieces of paper and write down every name you can think up. That’ll keep you busy for ages.

At your first meeting you should make up a rule book. And the first rule should be no grown-ups or little/big brothers or sisters! The best clubs are always secret!

Now you have just about everything you need, except membership cards. These are very important and again you can speed a lot of time making them. 75 Why not leave some space for a photo of yourself? That will make the membership card really look like it.

So there you are, get clubbing! Once you get started you’ll think of loads of more interesting things to do!

A.That’s easy.

B.Enjoy your own club!

C.Invite a designer to join you.

D.What are you interest in?E.Some vacation is just around the corner.

F.Then you need to pick a name for your club.

G.Use a bright thick pen to make a special design.

问答题 简答题