题干

某化学实验小组欲探究盐酸、氢氧化钙两种物质的化学性质,取8支试管分别用A~H编号后,做如图实验.

(1)实验中观察到有气泡出现的试管是____ ,有沉淀生成的试管是 ____ .

(2)写出实验中无明显现象产生的试管中发生反应的化学方程式____ .

(3)实验后某试管中为红色溶液,当向其中加入过量的____ 后,溶液变为蓝色.由此推断,该试管中最初盛有的物质是____ .

上一题 下一题 0.0难度 选择题 更新时间:2018-09-02 07:31:25

答案(点此获取答案解析)

B、D,G、H,Ca(OH)2+2HCl=CaCl2+2H2O,NaOH溶液,紫色石蕊溶液

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完形填空。阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项。

    Virak Mao moved from Cambodia six and a half years ago. He was an exciting and 1 12-year-old boy,looking forward to his new life in Canada but fearful he wouldn't make friends, 2 since he didn't speak English. What great progress he has 3 since then.

    First of all, he got over those early difficulties and 4 friends. Mao not only mastered 5 but won the Grade 9 French award. At school, he 6 to organize school events. Mao also 7 at school, such as cleaning the library and helping others . Mao had wanted to be an engineer 8 after struggling with chemistry, he discovered a new passion for 9. At his Buddhist temple, Mao is a leader and 10 those who came to Canada for the first time to work hard. He also 11 in cultural dancing with other temple members, donating any 12 they raise back to the temple to buy supplies for the poor. Since the summer of 2011, he has held a job at a clothing store to help 13 his family. In June, Mao 14 from C.W. Jefferys and is now in the business management program at Ryerson University.

    He is also the first winner of a new scholarship 15 by the Graduate Business Council with the purpose of helping a student, 16 wants to improve his community and in 17 of money. Awarded the scholarship in June, Mao spoke about the 18 of the award. “I was so excited. It was a huge relief for me,” he said, adding he would buy textbooks and school supplies with the award. “I am really 19 they raised this money to award me the scholarship. I just have no words. Anyone who works hard gets well 20.”