问题 填空题

(一)下列实验操作中正确的是(填写序号)______.

A.蒸发操作时,待蒸发皿中的水分完全蒸干后再停止加热

B.分液操作时,分液漏斗中下层液体从下口放出,上层液体从上口倒出

C.蒸馏操作时,应使温度计水银球靠近蒸馏烧瓶的支管口处

D.把氢氧化钠固体放在托盘天平左盘的滤纸上称量

E.过滤操作中,为了加快过滤可用玻璃棒在漏斗中轻轻搅拌

F.配制溶液时,为了准确,溶解后应立即将溶液沿玻璃棒引流转移至容量瓶内

G.为加速固体物质的溶解可采用粉碎、振荡、搅拌、加热等方法

(二)海洋植物如海带、海藻中含有大量的碘元素,碘元素以碘离子的形式存在.实验室里从海藻中提取碘的流程如图:

(1)指出提取碘的过程中有关的实验操作名称:①______,③______;

(2)提取碘的过程中,可供选择的有机试剂是______.

A.苯、酒精   B.四氯化碳、苯   C.汽油、酒精  D.汽油、氢氧化钠溶液

(3)为使海藻灰中碘离子转化为碘的有机溶液,实验室有烧杯、玻璃棒、集气瓶、酒精灯、导管、圆底烧瓶、石棉网以及必要的夹持仪器、物品,尚缺少的玻璃仪器有______、______.

(4)从含碘的有机溶液中提取碘和回收有机溶剂,还须经过蒸馏,指出实验装置图中的错误之处:

①______;

②______;

③______.

(5)进行上述蒸馏操作时,使用水浴加热的原因是:______,最后晶态碘在______里聚集.

答案

一、A.蒸发操作时,待蒸发皿中的水分完全蒸干后再停止加热,晶体受热不均,容易溅出,应在有大量晶体析出时,停止加热,利用余热蒸干,故A错误;

B.活塞到漏斗管口还残留一部分下层液体.如果将上层液体也从下口放出,残留的下层液体会一起被放出,上层液体就不纯净了,故分液操作时,分液漏斗中下层液体从下口放出,上层液体从上口倒出,故B正确;

C.蒸馏操作中温度计控制的是馏分的沸点,温度计水银球靠近蒸馏烧瓶的支管口处,故C正确;

D.氢氧化钠固体具有腐蚀性,易潮解,不能放在滤纸上称量,应在玻璃器皿中称量,如烧杯,故D错误;

E.过滤实验中玻璃棒的作用是引流,防止液体溅出,用玻璃棒搅动漏斗里的液体,容易把滤纸弄破,使实验失败,起不到过滤的作用,故E错误;

F.配制溶液时,为了准确,应挥发到室温,再将溶液沿玻璃棒引流转移至容量瓶内,故F错误;

G.粉碎可以增大与溶剂的接触面积,搅拌可以改变固体周围的饱和状态,加速溶解,在试管内进行少量固体溶解可以用振荡,在烧杯内进行较多固体溶解可以用搅拌,加热可以增大分子的移动速率,可以加速固体的溶解,故G正确.

故选:BCG.

二、(1)操作①将浑浊液分成溶液和残渣的方法为过滤操作,操作③将碘从水溶液中转移到有机相中的过程为萃取.

故答案为:过滤;萃取.

(2)A.酒精与水互溶,故A错误;

 B.四氯化碳、苯与水不互溶,且碘在四氯化碳、苯中的溶解度远大于水中,故B正确;

 C.酒精与水互溶,故C错误;

D.碘与氢氧化钠溶液发生反应,故D错误.

故选:B.

(3)使海藻灰中碘离子转化为碘的有机溶液,涉及过滤操作与萃取操作,由给出的仪器可知,过滤操作缺少普通漏斗,萃取操作缺少分液漏斗.

故答案为:普通漏斗、分液漏斗.

(4)加热应垫石棉网,冷凝水应是下进上出,温度计水银球应与烧瓶支管口相平.

故答案为:缺石棉网;温度计插到了液体中;冷凝管进出水的方向颠倒.

(5)水浴加热受热比较均匀,容易控制温度.有机溶剂蒸出,碘留在蒸馏烧瓶内结晶.

故答案为:受热比较均匀,温度容易控制;蒸馏烧瓶.

单项选择题

Questions 52 to 56 are based on the following passage.
Good jobs are scarce these days, with roughly 15 million Americans out of work and a national unemployment rate of 10 percent. President Obama tried to address the jobs crisis in his State of the Union by proposing a $ 33 billion tax credit for small businesses to hire new workers and by calling unemployment the most pressing item on his schedule.
Apart from the federal government’s response to the jobs crisis, economists predict that certain industries such as health care, green technology, education and government, will grow in the coming years. Each week we search several job board--including Indeed, Vault and Yahoo to help us track the best job listings with salaries of $100 000 or more. For this week’s picks, we’ve presented jobs in new emerging fields:
The first one is Wind Energy Sales Director. Are you fascinated by the sight of wind power generator, or simply committed to conserving energy SKP USA, a Pennsylvania-based company that manufactures, sells, and maintains wind power generators, is looking for a senior-level sales executive with an MBA and an engineering background. Pros (优点): You’d get the chance to work on a wide range of renewable energy projects, including solar and tidal. Cons (缺点): The job would require the candidate to travel about 70 percent of the time, both home and abroad.
The second position is Sustainability Director. AECOM offers design, planning, engineering, and consulting services for urban design, city planning, environmental performance, and policy projects. Newsweek ranked AECOM one of the top 500 greenest companies in 2009. This position in D.C. oversees climate change and sustainability projects for clients that include federal, state, and city governments. Pros: The company has offices in 100 countries. Cons: Enthusiasm is not enough. They want to hire a self-promoter with published articles and a great speaker.
The third recommended position is Response Management Specialist. Don’t let this funny job title fool you. This position for the Defense Intelligence Agency. a support agency for the Department of Defense, involves mapping out how the agency is going to respond to disasters, including chemical or nuclear threats. Pros: As a federal employee, you’d get a pension and excellent benefits. Cons: You have to be willing to undergo a thorough background check.
The fourth position is Government Contract Manager. Somebody needs to track all of the money that governments and corporations spend on various contracts, enter the contract manager. This candidate needs to be organized, diplomatic, and analytical enough to recognize problems before they arise. Pros: You can be based in Washington, D.C., Reston, Va., San Diego, or Los Angeles. Cons: You need a minimum of six years of contract-management experience and must be willing to travel 50 percent of the time.

President Obama claimed the first problem he should handle is unemployment in order to ______.

A.draw attention to job crisis

B.get supports for the tax credit for small business

C.prove that his schedule was very busy

D.get new. better workers into small business

单项选择题