问题 选择题

现将10gA和足量B混合加热,A与B发生化学反应,10gA完全反应后生成8gC和4gD,则参加反应的A与B的质量比是

A.1:1

B.2:1

C.4:1

D.5:1

答案

答案:D

题目分析:生成物的总质量为8g+4g=12g,反应物的总质量为10g+B,根据质量守恒定律:参加反应的物质质量总和等于生成物的质量总和可知,10g+B=12g得B=2g。则参加反应的A与B的质量比10:2=5:1,D正确。

填空题

Part 4


Questions 26-45


·Read the following text and decide which answer bestfits each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.

How to Tell Which Side You Favor


Brain researcher Ned Herrmann tested more than 7,000 people to find out which side of the brain they favored. He found a p relationship between hemisphere (26) and the way subjects made a (27) : left-brain-oriented subjects were more often lawyers, writers, bookkeepers, doctors, tax experts, etc. —jobs (28) with logical, language-related information. Those who favored the right hemisphere (29) out to be poets, politicians, musicians, architects, entrepreneurs, dancers and (30) —top executives. Herrmann’s studies showed that the most successful people in any (31) are those who use both the left and right brains.
One test for hemisphere dominance is to (32) how you turn your head and eyes when (33) questions asked by someone in front of you. Research suggests that if you generally turn to the left, you have a right-brain (34) ; if you turn to the right, (35) are you prefer work that (36) use of logic or language.
Another test for dominance involves directions for (37) a product. A left-hemisphere- oriented person usually follows instructions in a step-by-step (38) —from written sentence to written sentence. Someone with p right-side input will probably (39) the written directions and assemble the pieces by (40) the diagram or picture.
If you think you’re right-brained, (41) this teaser. Read the sentence below carefully and count the number of f’s:
FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC
STUDY COMBINED WITH THE EXPERIENCE OF MANY YEARS.
Did you find all six fs If not, don’t be surprised. Only 15 percent of those who take this test (42) .If you counted less than six—most count three—you probably (43) the f in each "of". Since "of" is pronounced "ov", the verbal left hemisphere took the verbal (44) and overrode the right, "seeing" hemisphere; (45) forcing the wrong conclusion.

A.takes

B.puts

C.involves

D.has

单项选择题