(13分)在75℃左右,用HgSO4做催化剂,乙炔可水化为乙醛,但HgSO4遇到

题型:实验题

问题:

(13分)在75℃左右,用HgSO4做催化剂,乙炔可水化为乙醛,但HgSO4遇到某些特定物质常会发生催化剂中毒而失去催化作用,H2S就是其中一种:现用乙炔水化法,只用块状电石、浓硫酸、水、NaOH溶液、HgO粉末五种物质制乙醛,装置如下图所示,请回答下列问题;

(1)实验开始时,仪器A中盛放电石,B中应装____________,其作用是_____  ______    _____

___________________________________。

 (2)仪器D中盛放水,其作用是_________________________________________________。

(3)蒸馏烧瓶F中应加入HgO和另外两种试剂,若将三者分别直接加入,请按加入的先后顺序写出包括HgO在内的各试剂的名称____________________。将HgO加放F中的操作方法是________________

___________________。

(4)装置图中,加热F的方法叫___________,所选用温度计G的量程表示正确的是______。(填代号)。

A.0℃~50℃B.0℃~100℃C.0℃~200℃
D.50℃~100℃E. 0℃~360℃
(5)检验乙醛已制出的操作及现象______________________________________________。

考点:气体的收集、净化、干燥氯气的制取其他物质的制备(硫酸铜晶体、铁红等)乙烯的制取
题型:实验题

已知函数f(x)=2x-x2,x∈[4,5],对于f(x)值域内的所有实数m,满足不等式t2+mt+4>2m+4t恒成立t的集合是(  )

A.(-∞,-5)

B.(-∞,-2)∪(5,+∞)

C.(-∞,-5)∪(2,+∞)

D.(-∞,-5)∪(-2,+∞)

题型:实验题

改错。

( ) 1. We are happy family.        ______________

    A B   C

( ) 2. They are talk.      ______________

    A  B C

( ) 3. My family live in China.    ______________

     A   B  C

题型:实验题

日终,柜员采用“不清零”方式的,现金箱交金库保管;采用“清零”方式的,现金实物缴存主出纳,由主出纳缴存金库统一保管,“清零”后柜员现金箱可入营业机构保险柜或金库保管。

题型:实验题

政府无论调高或调低价格,其结果()

A.都会使消费者得到好处

B.都会使生产者得到好处

C.都会使供求失衡现象消失

D.都可能使供求失衡现象持续存在

题型:实验题

Tidiness


Tidiness means keeping things out of sight and yet available when wanted. It implies that there is a (1) for everything and that each thing used finds its way (2) to its place by a continuos process, not by a spasmodic (3) . The process depends, however, upon the drawer, cupboard and storage (4) being provided, for lack of which one things may literally have (5) place to go. Like the perambulator and trolley, the luggage and the golfclubs (6) be homeless. The same may be true of the deck-chairs (7) the bulkier plastic toys. As there is no place for them, it is no (8) telling people to put them away. The architect who thus economises on (9) space is apt to claim that a good-sized sitting-room is (10) result. What advantage is there in that, however, (11) half the living-room has to be used for storage The aesthetic (12) depends, in turn, upon storage space. (13) it may be true that no house ever had cupboards enough, (14) are some houses which have practically no cupboards (15) all. In these our choice must lie between chronic (16) and ruthless destruction. That is not to say, however, (17) cupboard space will itself create tidiness. Some people (18) happier, it would seem, in chaos. There is the question, furthermore, (19) the cupboards themselves are tidy. That (20) has been swept out of sight is no proof, in itself, that everything can be found.

更多题库