问题 实验题

(18分)某化学兴趣小组的同学利用下图所示实验装置进行实验。(图中a、b、c表示止水夹)。

请按要求填空:

(1)利用B装置可制取的气体有             (至少填2种),写出实验室里利用A装置制取氯气的离子方程式                               

(2)只用A、C、E相连后的装置用于制取Cl2并进行相关的性质实验。若在丙中加入适量水,即可制得氯水。将所得氯水分成两份,进行Ⅰ、Ⅱ两个实验,实验操作、现象结论如下:

实验序号实验操作现 象结 论
将氯水滴入品红溶液溶液褪色氯气与水反应的产物有漂白性
氯水中加入 NaHCO3粉末有无色气泡产生氯气与水反应的产物具有较强的酸性
 

①请评价实验Ⅰ、Ⅱ的结论是否合理?若不合理,请说明理由。 (任选1个实验进行评价。)   

实验序号结论理由
  
  
 

②若要利用上述A、C装置设计一个简单的实验,验证Cl2和I2的氧化性强弱,可以在甲、乙、丙中分别装入浓盐酸、MnO2、淀粉碘化钾溶液,根据丙中产生的现象是                        ,则可证明Cl2的氧化性强于I2

(3)B、D、E装置相连后,在B中盛装足量浓硝酸和铜片(放在有孔塑料板上),可制得NO2并进行有关实验。

①B中发生反应的化学方程式                             

② 欲用D装置验证NO2与水的反应,其操作步骤:先关闭止水夹        (填写a、b或c),再打开止水夹       (填写a、b或c),若要使D烧杯中的水进入试管丁的操作是:通过              试管丁,使试管丁的NO2气体逸出,NO2与水接触后即可引发烧杯中的水倒流进入试管丁。

答案

⑴  H2、CO2、H2S等(2分) MnO2+2Cl -+4H+ Mn2++Cl2↑+2H2O(2分)

⑵ ①实验Ⅰ结论不合理(2分),因为Cl2也有氧化性,此实验无法确定是Cl2还是HClO漂白…(2分);或者实验Ⅱ结论不合理……(2分),因为制取的氯气中含有HCl气体,HCl溶于水后能与NaHCO3粉末反应产生气泡……(2分)②试管中溶液由无色变为蓝色………(2分)

⑶①  Cu+4HNO3(浓)= Cu(NO3)2+2NO2↑+2H2O  ………(2分)

②a 、b ……(2分);    c ……(2分)    双手紧握(或微热)………(2分)

题目分析:(1)该装置的最大特点是可以控制反应的发生和停止,药品一般是固体和液体在常温下能反应,且不需要加热。例如实验室用锌和稀硫酸制取氢气,Zn+H2SO4=ZnSO4+H2↑,锌难溶于水,氢气难溶于水,当将装置中的导气管关闭后,生成的H2使装置中的气压增大,从而使固体和液体分离,使反应停止,所以能用图中的装置制取氢气;与此类似的该装置还可以制备CO2、H2S等;实验室利用二氧化锰氧化浓盐酸制备氯气,反应的离子方程式为MnO2+2Cl -+4H+ Mn2++Cl2↑+2H2O。

(2)①实验室制得的氯气中有杂质气体水蒸气和氯化氢气体,要进行干燥的氯气不具备漂白性的验证试验,再进行实验Ⅰ才能得到结论;氯化氢气体溶于水形成盐酸,盐酸也能和碳酸氢钠反应产生二氧化碳气体,不一定是氯气与水反应的产物的酸性;

②验证Cl-和Br-的还原性强弱可根据反应Cl2+2Br-=2Cl-+Br2设计实验,在A装置中制备氯气,生成的气体通入到装有溴化钠溶液的C中,如烧瓶中有黄绿色气体生成,试管中溶液由无色变为橙色,可证明氯气的氧化性强于溴;

(3)①浓硝酸具有强氧化性,与铜反应生成二氧化氮气体,反应的化学方程式为Cu+4HNO3(浓)=Cu(NO32+2NO2↑+2H2O;

②浓硝酸与铜反应生成的二氧化氮收集于试管丁中,由于二氧化氮能和水反应,则烧杯内气体的压强会减小,小于外界大气压,烧杯中的溶液会倒流于试管丁,所以要先关闭止水夹a、b,然后再打开止水夹c,用微热法使试管中气体逸出,NO2与水接触后即可引发烧杯中的水倒流入试管丁中,从而验证NO2与水的反应。

单项选择题
填空题

World Health Organization (WHO) officials recently urged Asia-Pacific governments to shake off complacency and intensify the fight against tuberculosis (TB), which kills 1,000 people a day in the region. Shigeru Omi, regional director of WHO for the Western Pacific, said deaths caused by tuberculosis continue to rise in the region as ’more and more people are infected with the dreadful disease every year.
"Every year, an additional two million tuberculosis cases are diagnosed in the region," Omi said at a news conference during the opening of a two-day meeting of Asian’ parliamentarians to discuss strategies to control the disease. (41) "When it comes to developed countries, the reason for the increase of TB is related to the ageing society," he said." (42) ""One common fact among developing countries and developed countries is complacency, "Omi added." (43) "
WHO said among the "high burden, high risk" countries in the region are Cambodis, China, Laos, Mongolia, Papua New Guinea, the Philippines and Vietnam. (44) It noted that more that 40 million people are infected with the disease and "10 percent of them -will develop TB in their lifetime. "In Cambodia, more than 7 million people, or 60 percent of the population, are infected with the disease, while in Vietnam more than 145, 000 people are infected each year. "In several developed and newly industrialized countries in the Western Pacific region, TB prevalence has not decreased markedly during the last decade although economic growth should make more resources available to deal with the problem, "WHO said. (45) .
Omi expressed confidence that with renewed vigilance among health officials in the region. TB prevalence could be reduced by half by 2010.
[A] If you become elderly, your immune system is becoming weaker and weaker.
[B] In Japan, the number of diagnosed cases rose to 48, 264 in 1999 from 42, 472 cases in 1996.
[C] Omi pointed out that the main factor for the rise of TB cases in developing countries is the rapid increase of people who migrate into the big cities and live in unsanitary conditions.
[D] There is no doubt that tuberculosis will be eliminated completely everywhere in the world in the near future.
[E] They thought we have already conquered tuberculosis, so they become a little bit complacent.
[F] WHO records showed that in China, tuberculosis is one of the most common causes of death.
[G] In Asia, the number of diagnosed cases rose to 148, 264 in 2001 from 42, 472 cases in 2005.