题干

请用化学知识解释下列问题:

①用稀有气体可制成霓虹灯,原因是____

②加热时试管炸裂____(写出一点);

③白炽灯泡钨丝上放少量红磷,其原因是____.

上一题 下一题 0.0难度 选择题 更新时间:2018-10-18 03:26:12

答案(点此获取答案解析)

通电发出各种有色光,加热时试管外壁有水,除去灯泡内少量的氧气.

同类题3

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。

    Two hundred years after Charles Darwin's birth, studies have found new details of his life at the University of Cambridge. Six leather-bound ledgers (皮革账本) discovered in the university show this.____

    He lived in the most expensive rooms provided for a rich student at his time.____He had someone to clean his room, make his bed and take care of the fire in his bright rooms. He hired a dishwasher, a clothes washer and a man who cleaned his shoes. A tailor (裁缝), hatter and barber made sure he was well presented. A chimney cleaner and a coalman kept his fire going. Christ's College's basic food was meat and beer.____

    Darwin's bill topped 636 pounds during his three years of study at Cambridge. Later he described this time as the most joyful of his happy life. That large sum (金额) would have been fairly common for a student at Cambridge in the 19th century.

    ____

    In those days Cambridge was full of rich students living a pretty good life and Darwin was just one of them.____And thus he had plenty of time for socializing or private study. He would be out shooting, collecting beetles, doing his scientific hobbies or visiting friends. He played cards and drank wine at night, just like students always have.

A. Thanks to the richness, he was able to hire servants to help with the daily life.

B. The findings were published on the Internet.

C. So he paid five and a half pence extra each day to have vegetables.

D. He enjoyed the kind of comfortable university life that most of today's students can only dream about.

E. He had several people to help him to deal with the daily housework.

F. When you look at the ledgers, you can find there were many rich students in Cambridge.

G. The bills were paid by his wealthy father, Robert Darwin, a doctor.