在浓CaCl2溶液中通入NH3和CO2,可以制得纳米级碳酸钙(粒子直径在1~10

题型:实验题

问题:

在浓CaCl2溶液中通入NH3和CO2,可以制得纳米级碳酸钙(粒子直径在1~100nm之间)。下图所示A~E为实验室常见的仪器装置(部分固定夹持装置略去),请根据要求回答问题。

(1)实验室制取、收集干燥的NH3,需选用上述仪器装置的接口连接顺序是(选填字母):

①a接_______,_______接_______,_______接h;

②用A装置制取NH3的化学反应方程式为______________________

(2)用下图所示装置也可以制取NH3,则圆底烧瓶中的固体可以选用__________(选填字母编号);

A.碱石灰 B.生石灰 C.无水氯化钙 D.无水硫酸铜 E.烧碱

(3)向浓CaCl2溶液中通入NH3和CO2气体制纳米级碳酸钙时,应先通入的气体是______________,试写出制纳米级碳酸钙的化学方程式__________________________;

(4)试设计简单的实验方案,判断所得碳酸钙样品颗粒是否为纳米级__________________________。

考点:其他物质的制备(硫酸铜晶体、铁红等)
题型:实验题

With the spread of inter-active electronic media a man alone in his own home will never have been so well placed to fill the inexplicable mental space between cradle and crematorium. So I suspect that books will be pushed more and more into those moments of travel or difficult defecation (1) people still don’t quite know what to do with.

When people do read, I think they’ll want to feel they are reading literature, or (2) something serious. (3) you’re going to find fewer books presenting themselves as no- nonsense and (4) assuming literary pretensions and being packaged as works of art. We can expect an extraordinary variety of genre, but with an underlying (5) of sentiment and vision.

Translators can only (6) from this desire for the presumably sophisticated. We can look forward to lots of difficult names and fantastic stories of foreign parts enthusiastically (7) by the overall worship of the "global village" Much of this will be awful and some wonderful, (8) don’t expect the press or the organizers of prizes to offer you much help in making the appropriate distinctions. They will be chiefly (9) in creating celebrity, the greatest enemy of discrimination, but a good prop for the (10) consumer.

Every ethnic grouping over the world will have to be seen to have a great writer--a phenomenon that will (11) a new kind of provincialism, more chronological than geographic, (12) only the strictly contemporary is talked about and (13) . Universities, including Cambridge, will include (14) their literature syllabus novels written only last year. (15) occasional exhumation for the Nobel, the achievements of ten or only five years ago will be largely forgotten.

In short, you can’t go too far wrong when predicting more of the same. But there is a (16) side to this--the inevitable reaction against it. The practical things I would like to see happen--publishers seeking less to (17) celebrity through extravagant advertising, (18) and magazines (19) space to reflective pieces--are rather more improbable than the Second Coming (耶稣复临). But dullness never quite darkens the whole planet. In their own idiosyncratic fashion a few writers will (20) be looking for new departures.

12()

A.which

B.where

C.when

D.what

题型:实验题

设函数f(x)=ax+cosx,x∈[0,π].

(Ⅰ)讨论f(x)的单调性;

(Ⅱ)设f(x)≤1+sinx,求a的取值范围.

题型:实验题

早餐前注射正规胰岛素,发生低血糖多在()

A.注射后半小时

B.注射后2~4小时

C.午餐后

D.晚餐前

E.夜间

题型:实验题

某仓储中心项目建设预计的现金流量表为:

假定该项目的行业基准折现率为12%,请根据表中数据计算该项目的NPV;

题型:实验题

跳汰机各室马达皮带轮直径分别为一室();mm、二室100mm、三室110mm、皮带型号为。

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