问题 选择题

高温下,反应2HBr(g)⇌H2(g)+Br2(g)(正反应为吸热反应)达到化学平衡时,要使混合气体的颜色加深,可采取的方法是(  )

A.减小压强

B.缩小体积

C.降低温度

D.增大氢气的浓度

答案

A、减小压强平衡不移动,但体积增大,c(Br2)减小,混合气体的颜色变浅,故A错误;

B、缩小体积,压强增大,平衡不移动,c(Br2)增大,混合气体的颜色变深,故B正确;

C、降低温度平衡向逆反应移动,c(Br2)减小,混合气体的颜色变浅,故C错误;

D、增大氢气的浓度,平衡向逆反应移动,c(Br2)减小,混合气体的颜色变浅,故D错误;

故选B

单项选择题
填空题


SECTION A
In this section you will hear a mini-lecture. You will hear the lecture ONCE ONLY. While listening to the lecture, take notes on the important points. Your notes will not be marked, but you will need them to-complete a gap-filling task on ANSWER SHEET ONE after the mini-lecture. Use the blank paper for note-taking.
Now listen to the mini-lecture.


Ben Buchanan and A, Magic Book
The Texas teen is devouring the 672 pages of Harry Potter and the Half-Blood Prince written by J. K.
Rowling. When Buchanan got the first Harry Potter book in 1998, he was struggling with difficulty in reading.
But when his mom read the first chapter aloud to him, he was determined to conquer his first "real" book.
I. The success of Rowling’s books:
1) over (1)______ of Rowling’s books printed in U.S..(1) ______
2) kids’reading and (2)______ each title fervently. (2) ______
However, whether all of this hype of countdowns and midnight trips to book-
stores translates into a lifelong reading habit remains unclear.
II. Our society now needed a reading renaissance:
1) A study shows: adult (3)______ have dropped 10 percentage points. (3) ______
A. the loss of readers possiblly (4)______ to the booming world of technology;(4) ______
B. (5)______ offer experience that can’t be gained from these other sources. (5) ______
2) Thr facts reflect: fewer kids are reading for (6)______. (6) ______
A. This (7)______ retreat from books not taken a toll on reading ability. (7) ______
B. this indicates a poor future in reading ability development—the
very reason why many educators are hoping the Harry Potter
series can work some (8)______. (8) ______
III. The Harry Potter series has "broken the rules":
1) the book was as exciting as a video game;
2) 59 percent of U.K. kids think the books have (9)______ their reading skills; (9) ______
3) (10)______. say the books are the reason they read more. (10) ______
Part of the allure of The Harry Potter is the thrilling story, with well-developed characters and an avalanche of magical moments.