问题 实验题

废易拉罐的成分比较复杂,据查,铝易拉罐各部分成分及含量(质量百分含量)见表:

 SiFeCuMnMgCrZnTiAl
罐身/%0.30.70.250.251.0~1.5   其余
罐盖/%0.20.350.150.2~0.54.0~5.0 0.10.25其余
拉环/%0.20.350.150.2~0.53.0~4.00.10.250.1其余
 

为了验证罐身的组成成分,进行了如下实验:

【实验仪器与药品】

仪器:酒精灯、烧杯、试管、试管夹、漏斗、滤纸、铁圈、玻璃棒、砂纸、剪刀

药品:易拉罐、去污粉、NaOH溶液、KSCN溶液、盐酸、镁试剂、高碘酸(H3IO6,弱酸)

【实验方案】

实验预处理:将剪好的易拉罐片用砂纸打磨,除去表面的涂料层,直到光亮后用去污粉清洗干净备用。

【实验过程】分别向试管a、b中加入少量上述易拉罐片,进行如下操作:

请填写下列空白:

(1)图中操作①②所用到的玻璃仪器有                             

(2)沉淀A的成分为              

(3)操作③观察到的现象为              ;反应的离子方程式为                 

                                      

(4)若试管a、b中取样相同,则分别加入足量的NaOH溶液、稀盐酸后,相同条件下理论上产生的气体体积V(a)       V(b)(填“>”、“<”或“=”)

答案

(1)漏斗、烧杯、玻璃棒(每个1分,共3分)

(2)Fe、Cu、Mn、Mg等(全对得2分,漏写得1分,错写不得分)

(3)开始生成白色沉淀,并逐渐增多,后沉淀部分溶解(2分);H++ AlO2-+H2O=Al(OH)3↓(2分);2H++ SiO32-=H2SiO3↓(2分);Al(OH)3+3H+=Al3++3H2O(2分)(书写时不要求顺序)

(4)<(2分)

题目分析:

(1)过滤使用到的有漏斗、烧杯、玻璃棒。

(2)不溶于NaOH溶液有Fe、Cu、Mn、Mg等。

(3)Na2SiO3和NaAlO2溶液中加入盐酸开始生成白色沉淀,并逐渐增多,后沉淀部分溶解;H++ AlO2-+H2O=Al(OH)3↓;2H++ SiO32-=H2SiO3↓;Al(OH)3+3H+=Al3++3H2O。

(4)根据金属的含量可以看出与盐酸反应的金属量多,放出气体较多。

单项选择题
单项选择题

An eight-year-old child heard her parents talking about her little brother. All she knew was that he was very sick and they had no money left. When she heard her daddy say to her (1) mother," (2) a miracle can save him now", the little girl went to her bedroom and took out her piggy bank. She (3) all the change out on the floor and counted it carefully. Then she (4) her way six blocks to the drugstore.

"And what do you want" asked the shopkeeper. "It’s (5) my little brother," the girl answered back. "He’s really, really sick and I want to buy a (6) . His name is Andrew and he has something (7) growing inside his head and my daddy says only a miracle can save him. " "We don’t (8) miracles here, child. I’m sorry." the chemist said, smiling (9) at the little girl.

In the shop was a (10) customer. He stooped down and asked the little girl, "What kind of miracle does your brother (11) " "I don’t know," she replied. "He’s really sick and mommy says he needs (12) . But my daddy can’t pay for it, so I have brought my (13) .""How much do you have" asked the man. "One dollar and eleven cents, (14) I can try and get some more," she answered quietly. "Well, what a coincidence," smiled the man. "A dollar and eleven cents—the (15) price of a miracle for little brothers. (16) me to where you live. I want to see your brother and (17) your parents. "

That well-dressed man was Dr Carlton Armp, a doctor. The operation was completed without any (18) and it wasn’t long before Andrew was (19) again. The little girl was happy. She knew exactly how much the miracle cost—one dollar and eleven cents—also the (20) of a little child.

4()

A.went

B.made

C.took

D.found