反应2SO2+O22SO3在一定温度下达到平衡，下列说法正确的是( ) A．增大_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

反应2SO₂+O₂ 2SO₃在一定温度下达到平衡，下列说法正确的是( )

A．增大压强，平衡向右移动，平衡常数K增大

B．此时一定满足c(SO₂)=2c(O₂)

C．增加O₂的浓度平衡向右移动，SO₂的转化率增大

D．平衡向右移动时反应物的浓度减小，生成物的浓度增大

答案

答案：C

平衡常数只与温度有关系，改变压强，平衡常数不变，A不正确；平衡时SO₂和氧气的浓度不再发生变化，但二者不一定满足2倍的关系，B不正确；增大氧气的浓度，平衡向正反应方向移动，SO₂的转化率增大，C正确；D不正确，平衡向正反应方向移动，反应物的浓度不一定减小，生成物的浓度不一定增大，答案选C。

单项选择题

甲乙两个乡村阅览室，甲阅览室科技类书籍数量的1/5相当于乙阅览室该类书籍的1/4，甲阅览室文化类书籍数量的2/3相当于乙阅览室该类书籍的1/6，甲阅览室科技类和文化类书籍的总量比乙阅览室两类书籍的总量多1000本，甲阅览室科技类书籍和文化类书籍的比例为20：1，问甲阅览室有多少本科技类书籍（）

A．15000

B．16000

C．18000

D．20000

完形填空

完形填空（共20小题；每小题1.5分，满分30分）
On August 26,1999,New York City was struck by a terrible rainstorm.The rain caused the streets to 51 and the subway system almost came to a stop.
Unfortunately,this happened during the morning rush hour.Many people who were going to work were 52 to go home.Some battled to 53 a taxi or to get on a bus.Still others faced the 54 bravely,walking miles to get to work.
I 55 to be one of people on the way to work that morning.I went from

subway line to subway line only to find that most 56 had stopped.After making my way 57 crowds of people,I finally found a subway line that was 58 .Unfortunately,there were so many people waiting to 59 the subway that I could not even get down the stairs to the 60 .So I took the train going in the opposite direction,and then switched back to the downtown train.Finally,after what seemed like forever,the train 61 my stop.Then I had to walk several blocks in the increasingly heavy rain.When I finally got to my office,I was 62 through,exhausted and 63 .
My co-workers and I spent most of the day drying off.When it was 5∶00 pm,I was ready to go home.I was about to turn off my computer 64 I received an email from Garth,my Director:
I would like to thank all of you who made the effort and 65 reported to work.It is always reassuring (令人欣慰),at times like these,when employees so clearly show their 66 to their jobs.Thank you.
Garth’s email was short,but I learned more from that 67 message than I ever did from a textbook.The email taught me that a few words of 68 can make a big difference.The rainstorm and the traffic 69 had made me tired and upset.But

Garth’s words immediately 70 me and put a smile back on my face.

B．discouraged

B．appreciation