问题 填空题

炎热的夏天,池塘里常有大量的气泡从水中冒出,小莉同学想通过实验来检验此气体,设计了如右图甲所示的取气方法:将空的纯净水瓶装满水,瓶口向下对准冒出的气泡来收集气体.

(1)这种收集气体的方法叫______,由于瓶口偏小不便于收集,你的改进方法是______

(2)如图乙所示,若用水将瓶中收集到的气体排出,进水管应接______导管(填A或B).

(3)若将这种气体依次通过盛有氢氧化钠溶液(除去可能混有的CO2)和浓硫酸(吸收水蒸气)的

洗气瓶后,在尖嘴导管口处可以点燃,在火焰上方罩一个干燥而冷的小烧杯,发现烧杯内壁有水珠出现,将烧杯倒转过来,迅速向其中加入少量澄清石灰水并振荡,石灰水变浑浊.由此分析该气体中肯定存在含______元素的可燃性气体.写出石灰水变浑浊的化学反应方程式______.

(4)图乙除可以用作储气外,还可以用于洗气和集气等,按要求回答下列问题:

①若要除去CO中混有的CO2,瓶内盛______,气体从______管(填A或B)通人.

②用图乙所示的装置,请你设计三种方案收集一瓶氢气.

方案1:______;

方案2:______;

方案3:______.

答案

(1)池塘中的气体将瓶中水排出,这种排出水收集气体的方法称为排水集气法;瓶口偏小,可以插入漏斗以扩大收集气体的面积;

故答案为:排水法;将倒置的漏斗插入瓶口;

(2)注入的水将聚集于瓶底,把气体压至瓶上部,而气体应从瓶上部导管排出;

故选A;

(3)杯壁有水出现,说明气体燃烧生成了水,则气体中含H元素;澄清石灰水变浑浊,说明燃烧生成了二氧化碳,有二氧化碳生成说明气体含C元素;二氧化碳与澄清石灰水反应生成碳酸钙沉淀和水;

故选C、H(或碳、氢);Ca(OH)2+CO2=CaCO3↓+H2O;

(4)①在瓶内加入适量氢氧化钠溶液,并把混合气体从a管通入,使气体通过氢氧化钠溶液洗涤后排出;二氧化碳能与氢氧化钠反应生成碳酸钠和水而被吸收而除去;

故答案为:氢氧化钠溶液(或NaOH溶液);A;

②图乙的装置,若氢气从A管通入,则瓶内气体从B管排出,这属于向下排气法收集氢气;而把装置倒转,从A管通入氢气,瓶内空气将从B管排出,此仍为向下排气法收集氢气;装置内装满水,氢气从b管通入水则会在压强作用下从a管排出而收集一瓶氢气;

故答案为:氢气从B管通入;瓶内装满水,氢气从B管通入;装置倒置,氢气从A管通入.

选择题
阅读理解

阅读理解

     Sixteen years ago, Eileen Doyle's husband, an engineer, took his four children up for an early morning

cup of tea, packed a small case and was never seen or heard of again.Eileen was astonished and in a

state of despair.They had been a happy family and, as far as she knew, there had been nothing wrong with their marriage.

       Every day of the year a small group of men and women quietly pack a few belongings and without so much as a note or a goodbye close the front door for the last time, leaving their debts, their worries and

their confused families behind them.Last year, more than 1,200 men and nearly as many women were

reported missing from home-the highest in 15 years.Many did return home within a year, but others

rejected the past completely and are now living a new life somewhere under a different identity.

      To those left behind, this form of desertion (遗弃) is a terrible blow to their pride and selfconfidence.

Even the finality of death might be preferable.At least it does not imply rejection or failure.Worse than that, people can be left with an unfinished marriage, not knowing whether they will have to wait several years

before they are free to start a fresh life.

      Clinical psychologist Paul Brown believes most departures of this kind to be well planned rather than

impulsive."It's typical of the kind of personality which seems able to ignore other people's pain and

difficulties.Running away, like killing yourself, is a highly aggressive act.By creating an absence the people

left behind feel guilty, upset and empty."

1. When her husband left home, Eileen Doyle ________.

A. could not forgive him for taking the children

B. had been expecting it to happen for some time

C. could not understand why

D. blamed herself for what had happened

2. Most people who leave their families behind them ________.

A. do so without warning

B. do so because of their debts

C. come back immediately

D. change their names

3. Which might be the title of the passage?

A. Broken marriage

B. New life after desertion

C. A new social problem

D. Desertion and its influence

4. What can be inferred from the passage?

A. Many people choose to leave home quietly because they hate their family.

B. Paul Brown regards leaving home as an act of selfishness.

C. Those who are left behind will lose confidence and won't marry again.

D. Eileen's husband, together with his four kids, was probably killed in an accident.