搜题请搜索小程序“爱下问搜题”
问题 选择题

已知C6H14有多种同分异构体，则其同分异构体中沸点最高的分子的一氯取代物的种数是

A．2

B．3

C．4

D．5

答案

答案：B

题目分析：根据有机物的同分异构体中支链越多沸点越低，得出C6H14中沸点最高的分子为直链分子，所以其一氯代物的种数即为等效氢的种数3种，答案选B。

填空题

Kofi Annan says helping survivors of last week’ s earthquake and (1) . in the Indian Ocean is (2) . The United Nations secretary-general says countnes that have offered aid must (3) and provide it. The offers add up to around (4) dollars. Unitd Nations officials say (5) of that is needed during the next six months.
The concern about offers of international aid is (6) . For example, the earthquake in Bam, Iran, in (7) of 2003 killed more than (8) people. Countries and groups offered hundreds of millions of dollars (9) . The United Nations says it has (10) only about (11) dollars in aid received so far. Governments and organizations that offered help (12) that, however.
On (13) Mr. Annan met with world leaders in Jakarta, Indonesia to discuss aid for (14) . The leaders discussed and (15) the idea of (16) owed by affected nations. But the leaders did not say they would do so. Some said that (17) to survivors would be more helpful.
Representatives of (18) countries and international organizations attended the meeting in Jakarta. Officials say they will cooperate to develop (19) for the Indian Ocean and the (20) .
查看答案
多项选择题

下面关于砂浆组成的表述正确的是（）。

A、水泥砂浆由水泥、沙子按一定比例配制搅拌而成

B、混合砂浆由水泥、石灰膏、沙子比例配制搅拌而成

C、水泥砂浆用在受湿度较大的墙体、基础部位

D、混合砂浆用于地面以上墙体的砌筑
查看答案