问题 选择题

能够充分说明在恒温恒容下的密闭容器中反应:2SO2+O22SO3,已经达到平衡的标志是

A.容器中SO2、O2、SO3共存

B.容器中SO2和SO3的浓度相同

C.容器中SO2、O2、SO3的物质的量为2︰1︰2

D.容器中压强不随时间的变化而改变

答案

答案:D

A 错误 任何可逆反应在任何状态下反应混合物均共存;

B错误 容器中SO2和SO3的浓度是否相同,取决于反应的起始状态,此不能作为达平衡的标志;

C 错误2︰1︰2只是反应过程中反应物及生成物在反应过程中的物质的量之比,不能作为达平衡的标志;

D 正确只有容器中压强不随时间的变化而改变才说明在恒温恒容下的密闭容器中气体分子总数不变,正逆反应速率相等即反应达平衡状态。

阅读理解

In Singapore, many middle school students spend lots of their time on their studies.Most people think good education is a ticket to success(成功)in their future. So, many of these students try their best to get a good mark in their exams. They have a lot of homework every day and exams are a big trouble. Sometimes, some of them are even made to go to after-school classes.

Schools run activities outside school hours. The students can join in sports and games, music and dance, swimming and climbing, etc. They are also very interested in community service(社区服务).

In their spare time, most students like to listen to pop music. Hollywood blockbusters(大片), Hong Kong and Singapore movies are very popular among them. They understand IT very well. Some of them also spend their free time searching the Internet, e-mailing their friends, playing computer and video games.

They sometimes go to cafes, fast-food restaurants, shopping centers and big bookshops.

So, life as a middle school student in Singapore is not easy but it is rich and colorful.

小题1:Many students want to get good education to be ________ in the future.

A.popular

B.successful

C.interesting

D.happy小题2:_____ __ go to after-school classes in Singapore.

A.A11 of the students

B.Few of the students

C.Not all the students

D.Most of the students小题3:According to the passage,most students in Singapore like     _____

A.Hollywood blockbusters

B.writing to their friends

C.talking to their friends

D.having exams小题4:The meaning of the underlined sentence in the passage is       __

A.the middle school students' life in Singapore is easy.

B.the middle school students' life in Singapore is amazing.

C.the middle school students' life in Singapore is boring.

D.the m.iddle school students' life in Singapore is hard, but it's interesting.

单项选择题