题干

下列实验“操作和现象”与“结论”对应关系正确的是(   )

操作和现象

结论

A

向装有Fe(NO32溶液的试管中加入稀H2SO4,在管口观察到红棕色气体

HNO3分解生成了NO2

B

向淀粉溶液中加入稀H2SO4,加热几分钟,冷却后再加入新制Cu(OH)2浊液,加热,没有红色沉淀生成

淀粉没有水解成葡萄糖

C

向饱和Na2CO3溶液中通入足量CO2,溶液变浑浊

析出了NaHCO3

D

向无水乙醇中加入浓H2SO4,加热至170℃产生的气体通入酸性KMnO4溶液,红色褪去

使溶液褪色的气体是乙烯

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:2017-03-02 08:40:20

答案(点此获取答案解析)

C

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     Qi Haoran, a Junior Grade One student at a High School Attached to Harbin Institute of Technology, was quite busy over the past winter holiday – and not just with homework. Qi, together with 10 other classmates made a volunteer group to call on people to join the Clean Your Plate Campaign (光盘行动).

     These students went to many restaurants and told people the importance of saving food. “Excuse me, do you know that 950 million people around the world still haven't got enough to eat? Please don't waste food.” They would say this kind of thing hundreds of times every day.

     The Clean Your Plate Campaign began on the Internet in January. It calls on people to reduce food waste. China in recent years has experienced serious problems with wasted food. CCTV reported in January that the food Chinese people waste every year is enough to feed 200 million people for a year.

     Chinese people are well-known for being hospitable(好客的) and generous. Many even feel that they lose face if their guests have eaten all the food.

     Luckily, the campaign has got the support of many. In a restaurant in Xinjiang, the owner gives the guests who have eaten up all that they ordered a sticker(贴花). People can enjoy a free meal when they have 10 stickers. More than 750 restaurants in Beijing have begun to offer smaller dishes and encourage their guests to take leftovers (剩饭剩菜) home.

     To reduce food waste is a big task, and it needs time. It's important that everyone does their bit, just like Qi. Did you finish your meals today?