问题 实验题

请你和小明一起进行实验室制取二氧化碳的探究实验。

(1)检查仪器药品:下面是实验桌上摆放好的该实验所需的用品。指出图中编号标识的各仪器的名称:

         ___,②           ,③          。其中②仪器也可换成_________________,该仪器与②仪器相比较,②仪器的优点是                    。为使该仪器较易插入橡皮塞的方法是___________                        ____.

(2)如果要制取二氧化碳,下图中缺少的仪器是     ________ ,缺少的药品是     ___________  

(3)选择装置。

通过对制取二氧化碳反应原理的分析,他选择   _____ (填仪器编号)组装成二氧化碳的发生装置,你认为他选择的依据是                        ______,写出此装置中制CO2的反应方程式______________________________;选择__________(填编号)组装成二氧化碳的收集装置。如果是收集氧气还可以采用_________收集,理由                                                  

(4)鲜鸡蛋会通过鸡蛋壳的小孔呼出二氧化碳,为保鲜鸡蛋,可把鸡蛋放到石灰水中,写出反应方程式________________________________。

答案

(1)锥形瓶 分液漏斗集气瓶 长颈漏斗 可以控制加液体药品的量  长颈漏斗的下端蘸水插入

(2)镊子 稀盐酸

(3)  a  b 反应物是固体与液体,不需加热  CaCO3 + 2HCl =CaCl2 +H2O +CO2  c  d  排水法 氧气不易溶于水

(4)Ca(OH)2 +CO2 =CaCO3↓+H2O

题目分析:(1)根据实验室常用仪器回答,图中仪器①的名称是锥形瓶,仪器②的名称是分液漏斗,仪器③的名称是集气瓶;其中②分液漏斗可用长颈漏斗来代替,但②分液漏斗可以通过调节活栓来控制所加液体药品的量,而长颈漏斗则不能;根据实验经验,为使该仪器较易插入橡皮塞,可将长颈漏斗的下端蘸水插入,并旋转推进。

(2)实验室常用石灰石或大理石和稀盐酸反应制取氢气,结合图示可知,缺少的药品是稀盐酸;而取用块状石灰石时,要用镊子,图示中未提供。

(3)实验室在用石灰石和稀盐酸反应制取二氧化碳的同时,还生成了氯化钙和水,故反应的化学方程式为CaCO3 + 2HCl = CaCl2 + CO2↑+ H2O;由此可知,该反应是固液体在常温下的反应,故制取气体的发生装置为“固液体不加热型”,故选a、b作为气体制取的发生装置;由于CO2密度比空气大且能溶于水,故只能用向上排空气法收集二氧化碳气体,故选c、d;如果是收集氧气,由于氧气不易溶于水,故还可以采用排水法收集。

(4)二氧化碳能与澄清石灰水反应,生成碳酸钙沉淀和水,故反应的化学方程式为Ca(OH)2 +CO2 =CaCO3↓+H2O。

点评:熟记氧气和二氧化碳的实验室制法、原理和操作注意事项,是解题的关键;此外,本题的重点是常用气体的发生装置和收集装置的选取方法,要学会根据反应物的状态和反应的条件选择发生装置,根据制取气体的溶解性和密度的大小选择收集气体的方法。

阅读理解

Cheating is when a person misleads, deceives or acts dishonestly on purpose. 小题1:If a basketball team is for kids under 8,it's cheating for a 9-year-old play on the team. At school, in addition to cheating on a test, a kid might cheat by stealing someone else's idea for a science project. 小题2:This kind of cheating is called plagiarizing (抄袭).

小题3:Jeff is doing it by sneaking answers to a test. And it's also cheating to break the rules of a game or contest or to pretend something is yours when it isn't. When people cheat, it's not fair to other people.

It's tempting(诱惑人的) to cheat because it makes difficult things seem easy, like getting all the right answer on the rest. 小题4:And it won't help on the next test-unless the person cheats again.

小题5:They want to get good grades but hate hard work. Other kids might feel like they can't pass the test without cheating. Even though there seems to be a "good reason" for cheating, cheating isn't a good idea.

A.Some kids cheat because they're lazy.

B.Cheating can happen in a lot of different ways.

C.But it doesn't solve the problem of not knowing the material.

D.Some kids cheat once and feel so bad that they never do it again.E. For kids, cheating may happen at school, at home, or while playing a sport.

F. There are plenty of reasons why a kid shouldn't cheat, but some kids have already cheated.

G. Kids may also cheat by copying a book report off the Internet and handing it in as it's his or her original work.

综合