问题 选择题

下列关于“化学之最”,说法正确的是:(   )

①铝是地壳里含量最多的金属元素②油脂是产生能量最高的营养物质③H2O在第二周期和第VIA元素氢化物的沸点中均是最高的④乙炔是含碳量最高的烃⑤甲烷是含氢量最高的气态氢化物⑥HCl是卤化氢中沸点最低的⑦Na是短周期元素中原子半径最大的⑧Al3+是第三周期离子半径最小的

A.①②④⑤⑦

B.除④外全对

C.①②⑤⑥

D.全对

答案

答案:B

题目分析:④:乙炔不是含碳量最高的烃。含碳量“最高”的烃的含碳量没有上限,只有上界100%。因为完全可以构造一个有很多碳原子组成的分子(例如C60,但60不是上限),然后再拆掉其中局部的结构填上一个氢原子,那样含碳量很接近100%——至于稳定性则另当别论,故错。故选B。

点评:本题是一道元素周期表结构、元素周期律以及有机物知识的综合题目,要求学生具有分析和解决问题的能力,难度不大。

完形填空

What do you do if you don't get into your first choice of university? That's the question      faces thousands of students in Britain every year.

Many students turn to Clearing, an education agency that helps      (find) university places for students at the last moment.       students don't have enough marks to get into their first choice of universities, Clearing tells them about places available at other universities, though they might have to study another subject.

But this year has seen a record number of students     want to study in universities. This means that there's been a fiecer competition for university places than usual. Education officials say six students competed for one place. It’s said almost 190,000 students still don't have a place in a university. That's a rise of over 46,000 students from last year.

       (face) with these numbers, some students are going to be disappointed, others might be thinking of an interesting choice: studying abroad. The University of Nottingham, for example, is offering places in Ningbo, near Shanghai.

                the problems with university entrance, the UK's Higher Education Minister, David Willetts, encourages students to study at home or to learn one kind of skills, such as cooking, hairdressing and so on .      some people say that rising university costs, less hope to find jobs in the future, and a drop in graduate recruitment(大学招生)mean it's      (bad) time to be a university student in the UK.

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