问题 填空题

如图所示,A、F为石墨电极,B、E为铁片电极。按要求回答下列问题:

(1)打开K2,闭合K1,B为_______极,A的电极反应为_____,最终可观察到的现象是      

(2)打开K1,闭合K2,E为_______极,检验F极产生气体的方法是                     。该装置中发生反应的化学方程式为_________。

(3)若往U型管中滴加酚酞,进行(1)、(2)操作时,       极周围能变红(填A、B、E、或F)。

(4)若电源选用燃料电池,结构如下图,以熔融碳酸盐为电解质(非水溶济,能够传导CO32-),电池工作时电解质组成保持稳定,通入甲烷的电极为________极,请写出正极反应的方程式         ,若在标况下消耗11.2L的甲烷,电解NaCl溶液产生的H2的物质的量为        mol(假设燃料电池能量转化率为75%)。

答案

(1)负;(2分)O2+2H2O+4e===4OH;(2分)溶液中有红褐色沉淀生成(2分)(2)阴;(2分)用湿润的淀粉碘化钾试纸靠近F极,试纸变蓝,

证明是氯气(2分)2NaCl+2H2O2NaOH+H2↑+Cl2↑(2分)(3)A、E;(4分)

(4)负(2分)  2CO2+O2+4e-=2CO32-(2分);1.5(3分)

题目分析:(1)打开K2,闭合K1,则构成原电池,铁是负极,即B是负极,A是正极。此时发生铁的吸氧腐蚀,所以最终溶液中有红褐色氢氧化铁沉淀生成。

(2)打开K1,闭合K2,则构成电解池。E和电源的负极相连,作阴极,溶液中的氢离子放电。F和电源的正极相连,是阳极,溶液中的氯离子放电生成氯气。氯气具有氧化性,可用湿润的淀粉碘化钾试纸检验。

(3)根据以上分析可知,进行(1)、(2)操作时,OH分别在A和E极产生,所以在这两极溶液显红色。

(4)原电池中负极失去电子,发生氧化反应,甲烷在反应中被氧化,失去电子,所以在负极通入,空气在正极通入。由于电解质是熔融盐,能传递能够传导CO32-,所以正极的电极反应式为2CO2+O2+4e-=2CO32-。1mol甲烷在反应中失去8mol电子,11.2L甲烷是0.5mol,共转移电子4mol。根据得失电子守恒可知生成氢气是

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Oscar-winning director Ang Lee' s new epic "Life of Pi" reveals the relationship between a teenage Indian boy and a Bengal tiger. But in reality, the predators(食肉动物)are under increasing threat from humans. Animal rights group PETA is hoping to use the popularity of the film to focus people's attention on the real life of Bengal tigers.

With the rising demand for tiger parts from East Asia, illegal hunting remains a tremendous danger for the remaining cat population. Back in 1947, there were 40,000 tigers in India, but the number is experiencing a sharp decline t0 1,706 despite campaigns to protect the animal.

Rising man-animal conflict is also one of the leading causes of decline in tiger numbers. In one of numerous reported attacks on the endangered big cats, villagers near The Bangladesh-India border, armed with sticks and boat oars, set upon the animal suspected to have attacked a local fisherman and beat it to death earlier this month. So far this year, 58 tiger deaths have been reported in the country.

"The first instinct when a tiger is spotted is to just kill it,"grieved Gurmeet Sapal, a wildlife filmmaker. "The feeling of fear and revenge is so strong that it shuts out any other emotion. What we don' t realize is that the tiger never attacks humans until it is forced to. "'

India has been struggling to stop the tiger's decline in the face of the loss of habitat as well that encourages the animals to leave the forest for food. " The tiger's rapidly exhausted prey base causes the predator to go al! out to get its food. Consequently, livestock and human beings become easy prey, which leads inevitably to conflict," says a wildlife conservationist.

Filmmaker Sapal says it is only normal for people to think of the tiger as a dangerous animal, but its image as a human killer bears some injustice. "Tigers never kill for sport nor store meat. They kill their prey only in case of hunger. " 

小题1:How can PETA take advantage over the hot movie “ Life of Pi ”?

A.PETA can count on the movie to promote people' s awareness of tiger' s life.

B.PETA can make enough money by encourage people to watch the movie.

C.The movie demonstrates that humans and tigers can live in harmony.

D.The movie offers a wonderful opportunity for movie to act in.小题2:Why did the villagers beat the tiger to death?

A.Because it was a human killer and attempted to attack people.

B.Because it was suspected to be a threat to local people' s lives.

C.Because local people just followed their instinct to kill it.

D.Because people wanted to carry out their revenge for it.小题3:According to the article, when will tigers attack and kill people?

A.When they are annoyed by people.

B.When they have conflict with people.

C.When they are driven to act in the movie.

D.When they are hungry or attacked.小题4:What contributes to the facts that livestock and human beings become easy target of tigers?

A.It is easier for tigers to hunt human beings than other animal for food.

B.Tigers are losing their habitat and forced to go out of the woods.

C.People hold a strong belief that tigers are a born threat to their lives.

D.Tigers can't be treated equally as other animal in the forest