问题 选择题

将铜粉和炭粉的混合物在空气中充分燃烧后,最终所得黑色物质与原混合物质量相等,则炭粉在原混合物中的质量分数为(  )

A.20%

B.80%

C.15.8%

D.84.2%

答案

由题意可知:氧化铜中氧元素的质量等于原混合物中炭粉的质量.

因此原混合物中炭粉的质量分数就是氧化铜中氧元素的质量分数.

氧化铜中氧元素的质量分数为

16
80
×100%=20%

故选A.

填空题
阅读理解

As a professor at a large American university, there is a phrase that I often hear from students: “I’m only a 1,050.” The unlucky students are speaking of the score on the Schoolastic Aptitude Test (SAT), which is used to determine whether they will be admitted to the college or university of their choice, or even if they have a chance to get a higher education at all. The SAT score, whether it is 800, 1,100 or 1,550, has become the focus at his time of their life.

It is obvious that if students value highly their test scores, then a great amount of their self-respect is put in the number. Students who perform poorly in the exam are left feeling that it is all over.The low test score, they think, will make it impossible for them to get into a good college. And without a degree from a prestigious university, they fear that many of life’s doors will remain forever closed.

According to a study done in the 1990s, the SAT is only a reliable indicator of a student’s future performance in most cases. Interestingly, it becomes much more accurate when it is set together with other indicators--like a student’s academic proficiency(学业水平).They will never be able to test things like confidence, efforts and willpower, and are unable to give us the full picture of a student’s potentialities. This is not to suggest that we should stop using SAT scores in our college admission process. The SAT is an excellent test in many ways, and the score is still a useful means of testing students. However, it should be only one of the many methods used.

小题1: The purpose of the SAT is to test students’ _________.

A.strong will

B.academic ability

C.full potentialities

D.confidence in school work小题2: Students’ self-respect is influenced by their_______.

A.scores in the SAT

B.achievements in mathematics

C.job opportunities

D.money spent on education小题3:“ A prestigious university” in para.2 is most probably _______.

A.a famous school

B.a technical school

C.a traditional school

D.an expensive school小题4: The passage is mainly about_______________.

A.how to prepare for the SAT

B.stress caused by the SAT

C.American higher education

D.the SAT and its effects小题5: What is the writer’s attitude towards the SAT?

A.Subjective

B.Objective

C.Critical

D.Approving