题干

铁、铜混合粉末17.6 g加入到800mL 1.0mol/L的 FeCl3溶液中,充分反应后,所得溶液中Fe2+和Cu2+物质的量浓度之比为8∶1。下列有关说法正确的是(   )

A:混合粉末中铁与铜的物质的量之比是1∶2

B:反应后的溶液最多还可以溶解铁粉5.6g

C:反应后所得溶液中c(Fe2+)=1.0mol/L (假设反应前后溶液体积无变化)

D:向反应后的溶液中加入2.0 mol/L NaOH溶液至金属离子恰好全部沉淀时,需加入NaOH溶液的体积是1.6 L

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C

同类题2

阅读下文,完成小题。

有一种雅量叫容人

    ①容人是一种美德,是一种思想修养,也是一种优良的生命质地,它喜与宽厚结伴,乐与谦和为伍。我们立身处事需有容人的雅量。

    ②容人要有用人之长的慧眼。人才是第一资源,只有网罗人才,吸引人才,用好人才,才能推动事业发展。刘邦出身低微,文才武略平平,却能一统天下,原因何在?刘邦在总结自己成功经验时讲过一段发人深省的话:“夫运筹策帏帐之中,决胜于千里之外,吾不如子房。镇国家,抚百姓,给馈饷,不绝粮道,吾不如萧何。连百万之军,战必胜,攻必取,吾不如韩信。此三者,皆人杰也,吾能用之,此吾所以取天下也。”用人之长是一种智慧,一种胸怀,一种境界。古今中外,还有许多容人之长的典范:徐庶推荐诸葛亮,而诸葛亮推荐庞统;徐特立将教育部长之职让给瞿秋白,自己甘当他的手下;钢琴演奏家李斯特则推荐当时并不出名的肖邦.

    ③容人要有谅人之短的胆识。金无足赤,人无完人。一般来看,越是在一个方面有突出才能的人,往往在另一个方面的缺点也更明显。美国南北战争时,林肯总统任命嗜酒贪杯的格兰特将军为总司令。当时有人告诫他,此人嗜酒贪杯,恐难担大任。林肯却不以为然。他何尝不知道酗酒可能误事,但他更清楚在诸将领中,唯格兰特是决胜千里的帅才。后来事实证明格兰特的受命正是南北战争的转折点。林肯在用人时能够扬人之长、谅人之短,颇受后人称颂。然而谅人之短并不是无原则的,所谓能容忍的“短”,必须是小节,是不影响大局的。如果是涉及根本原则、妨碍大局的短处,就不能谅解了。

    ④ 容人要有忘人之过的气度。“人非圣贤,孰能无过”。只要能宽容有过错的人,激励他改过自新,他就会迸发出无限的创造力,一心一意作贡献。在这一点上,***善待徐向前就是一个成功的范例,1937年,党内一致声讨惨败而归的西路军总指挥徐向前,惟***对其大加抚慰,并力排众议予以重用。最终在1948年,徐向前率领一支由地方武装改编而成的不足六万人的队伍,一个月内歼敌10万余人,解放县城14座,创造了军事史上的一个奇迹。人的一生难免会犯错,对待他人所犯的错误我们要公正看待,不以偏盖全,不苛责求全,而应宽其过、恕其失、抚其痛、安其心,让那些有发展潜质的人才不至于被一个缺点影响、被一个错误困住、被一个污点束缚。

    ⑤容人要有释人之怨的胸襟。不计前嫌,化敌为友,这是容人的极致。官渡之战前,陈琳为袁绍写讨伐曹操的檄文。在檄文中,曹操的祖宗三代都被骂得狗血喷头。曹操看了檄文之后竟连声称赞道:“陈琳的文章写得真不赖,骂得痛快。”官渡之战后,陈琳落人曹操之手。陈琳心想:当初我把曹操的祖宗都骂了,这下子非死不可了。然而,曹操不仅没有杀陈琳,还委任他做了自己的文书。陈琳深为曹操的宽宏大量所感动,竭尽全力辅佐曹操,使曹操颇为受益。

    ⑥“良匠无弃木,明主无弃士”。天空包容每一片云彩,不论其美丑,故天空广阔无比;高山包容每一块岩石,不论其大小,故高山雄伟壮观;大海包容每一朵浪花,不论其清浊,故大海浩瀚无涯.如果我们每一个人都有容人的雅量,谦虚待人、谦和处事、谦恭自居,何愁人与人之间不能理解,何愁世界不变得更加美好?

同类题5

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    While Jennifer was at home taking an online exam for her business law class, a monitor a few hundred miles away was watching her every move.

    Using a web camera equipped in Jennifer's Los Angeles apartment, the monitor in Phoenix tracked how frequently her eyes moved from the computer screen and listened for the secret sounds of a possible helper in the room. Her Internet access was locked-remotely-to prevent Internet searches, and her typing style was analyzed to make sure she was who she said she was: Did she enter her student number at the same speed as she had in the past? Or was she slowing down?

    In the battle against cheating,this is the cutting_edge and a key to encourage honesty in the booming field of online education. The technology gives trust to the entire system,to the institution and to online education in general. Only with solid measures against cheating, experts say, can Internet universities show that their exams and diplomas are valid—that students haven't just searched the Internet to get the right answers.

    Although online classes have existed for more than a decade, the concern over cheating has become sharper in the last year with the growth of “open online courses.” Private colleges, public universities and corporations are jumping into the online education field. Spending millions of dollars to attract potential students, while also taking steps to help guarantee honesty at a distance.

    Aside from the web cameras, a number of other high-tech methods are becoming increasingly popular. Among them are programs that check students' identities using personal information, such as the telephone numbers they once used.

    Other programs can produce unique exams by drawing on a large list of questions and can recognize possible cheaters by analyzing whether difficult test questions are answered at the same speed as easy ones. As in many university classes, term papers are scanned against some large Internet data banks for cheating.