题干

下列物质的鉴别错误的是(  )

选项

物质

试剂

现象和结论

A

氢气和氧气

带火星的木条

能使木条复燃者为氧气

B

一氧化碳和氢气

点燃

照在火焰上的干燥烧杯内壁出现水珠者是氢气

C

硫酸钠和碳酸氢钠

稀硫酸

有气体产生者是碳酸氢钠

D

硫酸铜和氢氧化铜

稀盐酸

溶液呈蓝色者是氢氧化钠

A:A 

B:B 

C:C  

D:D

上一题 下一题 0.0难度 选择题 更新时间:2019-07-12 06:01:48

答案(点此获取答案解析)

D

同类题5

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    What do the world's most successful people all have in common?

By examining the work habits of over 150 greatest writers and artists and scientists, the researchers including Stanford professor Jeffrey Pfeiffer found that high achievers like Robert Moses turned out to be all alike: 

Busy! Busy!

    ____ In a study of general managers in industry, John Kotter reports that many of them work 60 to 65 hours per week—which translates into at least six 10-hour days. The ability and willingness to work difficult and tiring hours has characterized many powerful figures. Energy and strength provide many advantages to those seeking to build power.

Just Say No!

    The difference between successful people and very successful people is that very successful people say “no” to almost everything. And that's what gives them the time to accomplish so much.____ And focus means saying “no” to a lot of distractions (分神).

____

    Ignore your weaknesses and keep improving your strengths. Don't waste time exploring skill areas where you have little competence. Instead, focus on—and build on—your strengths. This means knowing who you are, what you are and what you are good at.

Create Good Luck!

    ____ There's a science to it. Richard Wiseman studies lucky people for his book Luck Factor, and breaks down what they do right. Certain personality types are luckier because they behave in a way that offers the chance for good opportunities. By being more outgoing, open to new ideas, following the feeling that something is true, and being optimistic, lucky people create possibilities.

    Does applying these principles to your life actually work? Wiseman created a “luck school” to test the ideas—and it was a success. In total, 80 percent of the people who attended Luck School said that their luck had increased.____

A. Spend enough time to improve your weakness.

B. Achievement requires focus.

C. On average, these people reported that their luck had increased by more than 40 percent.

D. They never stop working and they never lose a minute.

E. Busy people are more likely to be lucky.

F. Know What You Are!

G. Luck isn't magical.