问题 实验题

(14分)制印刷电路的废液含有大量CuCl2、FeCl2和FeCl3,测得某废腐蚀液中含CuCl21.5 mol·L1、FeCl2 3.0 mol·L1、FeCl3 1.0 mol·L1、HCl 3.0 mol·L1。取废腐蚀液200 mL按如下流程在实验室进行实验,

回答下列问题:

(1)用上述方法获得的铜粉中含有杂质,除杂所需试剂是__________;检验废腐蚀液中含有存在Fe2+的方法是______________________(注明试剂、现象)。

(2)实验室可用浓盐酸和固体MnO2反应制备Cl2。此反应中体现了盐酸的_________性质,反应的离子方程式为____________________。

利用图1制备Cl2并通入到FeCl2溶液中获得FeCl3溶液。请从图2中挑选所需的仪器,完成图1中的装置简图(可添加必要的塞子、玻璃导管、胶皮管。不画固定装置),并标明容器中所装试剂名称。

(3)按上述流程操作,需称取Fe粉的质量应不少于_____________g,需通入Cl2的物质的量不少于_______________mol。 

答案

(14分)(每空2分)

(1) 稀盐酸      取少量腐蚀液,滴加KMnO4溶液,KMnO4溶液退色

(2) MnO2+4H+ +2ClMn2++C12↑+2H2O    酸性和还原性

(3) 39.2     0.75  

(1)由于加入的铁粉是过量的,所以得到的铜中一定含有铁,除去多余的铁粉,可以利用稀盐酸;亚铁离子具有还原性,据此可以鉴别,即取少量腐蚀液,滴加KMnO4溶液,KMnO4溶液退色。

(2)实验室制取氯气的方程式是 MnO2+4H+ +2ClMn2++C12↑+2H2O,根据方程式可知,氯元素的化合价升高,依次氯化氢是还原剂。另外还有氯化锰生成,元素浓盐酸还起酸性作用,即体现了浓盐酸的酸性和还原性。

(3)由于氯气有毒,所以必须有尾气处理装置,可以利用氢氧化钠溶液吸收多余的氯气。

(4)200ml腐蚀液中含有铁离子是0.2mol、铜离子是0.3mol、氢离子是0.6mol,则分别消耗铁的物质的量是0.1mol、0.3mol和0.3mol,所以至少需要加入铁粉的质量是0.7mol×56g/mol=39.2g。此时溶液中共计含有亚铁离子的物质的量是0.7mol+0.2mol+0.6mol=1.5mol,所以至少需要通入氯气0.75mol。

填空题

When I was growing up, I was embarrassed to be seen with my father. He (1) severely crippled and very short, and when we would walk together, his hand on my arm (2) balance, people would stare. I would inwardly be afraid (3) squirm at the unwanted attention. If he ever noticed or was bothered, he never let (4) .
It was difficult to coordinate (5) steps - his halting, mine impatient - and because of that, we didn’t say much as we went along. But as we started out, he always said, "You (6) the pace. I will try to adjust to you. "
Our usual walk was to or (7) the subway, which was how he got to (8) . He went to work sick, and (9) nasty weather. He almost never missed a day, and would (10) it to the office even if (11) could not: a matter of pride!
He never talked about himself as an object of pity, (12) did he show any envy of the more fortunate or able. What he looked for in others was a "good heart", and if he found one, the owner was good enough for him.
Now that I am older, I believe that is a proper standard (13) which to judge people, even though I still don’t know precisely (14) a "good heart" is. But I know the times I don’t have one myself.
He has (15) gone many years now, but I think (16) him often. I wonder if he sensed my reluctance to be seen with him during our (17) . If he did, I am (18) I never told him how sorry I was, how unworthy I was, how I regretted it. I think of him when I complain about trifles, when I am (19) of another’s good fortune, when I don’t have a "good heart".
At such times I put my hand on his arm to regain my (20) , and say, "You set the pace, I will try to adjust to you.\

单项选择题