问题 实验题

(5分)甲、乙两位同学分别用右图所示装置进行实验。

(1)甲同学验证燃烧的条件。取一小块白磷放入广口瓶中,一段时间白磷没有燃烧,然后从分液漏斗中加入适量的________,白磷仍然没有燃烧,再从a管通入________,白磷发生燃烧,该实验________(填“能”或“不能”)证明可燃物燃烧需要与氧气接触、温度达到着火点这两个条件。

(2)乙同学验证二氧化碳与水的反应。为验证使石蕊变色的物质是碳酸而不是水或二氧化碳,应该采取的实验操作顺序是_____________(填序号,可重复选用)。

① 从b端通氮气          ②将用石蕊溶液染成紫色的干燥纸花放入广口瓶中

③ 从a端通二氧化碳      ④从分液漏斗中滴加适量水

答案

(1)热水    氧气(或空气)   能

(2)②③①④③ 错答不得分。

题目分析:(1)根据物质燃烧的条件(可燃物、与氧气接触、温度达到着火点)进行分析,取一小块白磷(可燃物)放入广口瓶中,一段时间白磷没有燃烧,是因为没有与氧气接触,并且温度没有达到着火点,所以从分液漏斗中加入适量的热水,再从a管通入氧气(或空气),即可满足燃烧的条件,所以白磷燃烧了;通过该实验的前后对比,可以证明可燃物燃烧需要与氧气接触、温度达到着火点这两个条件。

(2)本题是验证使石蕊变色的物质是碳酸而不是水或二氧化碳,所以要先分别验证二氧化碳和水都不能使石蕊变色,然后再让二者反应生成碳酸,证明碳酸使石蕊变色;故要将石蕊溶液染成紫色的干燥纸花先放入广口瓶中②,然后从a端通二氧化碳③,此时用石蕊溶液染成紫色的干燥纸花不变色;此时,若直接从分液漏斗中滴加适量水,则水与集气瓶中的二氧化碳反应生成碳酸,继而使石蕊变色,则无法证明水不能使石蕊变色,所以要从b端通氮气①,以排除集气瓶中的二氧化碳;然后再从分液漏斗中滴加适量水④,此时用石蕊溶液染成紫色的干燥纸花仍然不变色;再从a端通二氧化碳③,则二氧化碳与水反应生成碳酸,此时用石蕊溶液染成紫色的干燥纸花变红,故填②③①④③。

点评:本题是课本实验的延伸,综合考查了学生的基本实验能力,对于此类验证型实验探究,要熟记物质的性质或变化规律,根据给出的实验设计方案,进行实验、分析和探究,并通过观察、记录和分析的实验现象,来验证该物质的性质或变化规律等。

完形填空

第二节:以下是五位专家的建议。请匹配这些建议及对应的生活感想或经验介绍(A、B、C、D、E和F)。选项中有一项是多余选项。请将答案代号(A、B、C、D、E、F)写在答题卷61~65的相应位置上。

61.        You should watch where your weight accumulates. You can use the waist. to. hip ratio to find if there is too much fat around the middle. Belly fat is especially dangerous because it release free fatty acids directly to the liver, virtually flooding it with fat.

62.        If a particular food is important to you, eat it, but work it off. You should try to learn the art of compromise.

63.        At the same time. the three-for-one is relatively simple to use. Fat grams and calories are listed on almost all boxed, canned or packaged foods—you have only to read the label and follow the rule. A five-year-old patient of mine can do this.

64.        Drinking water is basic, and drinking enough of it is necessary. Patients are sometimes surprised that basic things work when they do them consistently.

65.          Consume antioxidant foods. They protect the cholesterol C胆固醇), from oxidative damage, which helps prevent damage to blood…vessel walls.

A. More than nine years ago I was 70 pounds overweight and wore a very big dress. I had tried different diets and lost weight only to gain it back. Finally a simple “three. for. one’’ fat rule worked for me:consuming no more than three grams 0f fat for every 100 calories per serving. Following the rule and eating only foods that contain less than 30 percent fat, I spent eight months getting down to a size seven, and I’ve kept the weight off for nine years.

B. And for foods that aren’t packaged, you rely on what we already know about them. Red meat, as well as dishes made or served with butter, gravy, cream sauce or cheese, are almost never less than 30 percent fat—so you just don’t eat them. On the other hand, some non-packed foods—all fruits and vegetables。except avocadoes and olives—always pass the test. So do most fish。but not when fried.

C. I like vegetables, which are rich in vitamins. Most foods containing vitamins C and E(such as sweet potatoes, tomatoes, spinach and broccoli)are low in calories and are known as antioxidants(抗氧化物质). They can help reduce the possibility to develop hardening the arteries(动脉).

D. I gain weight around the belly—what we call abdominal obesity, the worst kind. The tendency seems to be hereditary(遗传的), and it’s common among men. This problem increases the risk of a stroke or heart attack. A guide I use in estimating belly fat is the waist-to—hip ratio, or WHR. To find yours. divide the circumference(周围)of your waist by the circumference of your hips. Women with ratios above 0. 8 and men with ratios above 1.0 are at increased health risk.

E. My ways of keeping healthy are very simple, and they are among our everyday activities:eating healthy food and doing exercise. In addition. I manage to do those basic things, such as drinking water, sleeping well and eating less fat. Sometimes I do some of the other things I used to do in my life like walking for half an hour a day.

F. Although I've put on ten pounds. I'm healthy and in good shape. I eat food that’s good for me…but 1 work off Susan’s homemade brownies(巧克力蛋糕), for example. To offset these extra calories, 1 walk for an hour or more, three times a week…often with Susan. We’re both busy and this is one way we have some quiet time together. Equally important, it permits me to practice dieting’s fine art of compromise.

单项选择题