碘化钠是实验室中常用的分析试剂，也常用于医疗和照相业。工业上用铁屑还原法制备Na

发布时间：2017-07-30 23:53 │ 来源：www.tikuol.com

题型：填空题

问题：

碘化钠是实验室中常用的分析试剂，也常用于医疗和照相业。工业上用铁屑还原法制备NaI，其主要流程如下图，请回答下列问题

(1)判断碘是否已完全反应的实验方法是____________；

(2)将滤液在低温下分离出NaI样品过程中，要防止NaI被氧化，最好采取的措施是________________；

(3)测定产品中NaI含量的方法是：

a．称取3.000 g样品、溶解，在250 mL容量瓶中定容；

b．量取25. 00 mL待测溶液于锥形瓶中；

c．用0.1 000 mol/LAgNO₃溶液滴定至终点，消耗AgNO₃溶液体积的平均值为19. 00 mL。

①上述测定过程所需仪器中，需要检查是否漏液的仪器有_____________。

②上述样品中NaI的质量分数为________________

③若用上述方法测定产品中NaI的质量分数偏低（测定过程中产生的误差忽略不计），其可能原因有

______________________

考点：工业生产其他物质（工业制备碳酸锂，硫酸钡等化工原理）其他钠盐（氯化钠、硫化钠、氮化钠等）

题型：填空题

完形填空。

     Robby was 11 years old when his mother sent him to have his first piano lesson. I prefer that students
begin at an earlier age, but Robby said  1 had always been his mother's dream to hear him play the
piano. So I took him on  2   my student.
     Although Robby tried very hard,  3 he was not good at music. However, he continued and  4 the end of
each weekly lesson he'd always say: "My mom is going to hear me play someday." But it
seemed hopeless. He didn't have a talent for music.
     One day, Robby stopped  5  to our lessons. He told me that his mom had been sick and unable to
take him to piano lessons, but he was still practicing. He asked  6 he could take part in my concert
and I agreed.
     The night of the concert came. The high school gym  7  with parents, friends and relatives. The concert
was going well. Then Robby came up on the stage, and began to play the piano.
     He played 8   well that everyone was on their feet, clapping (鼓掌) excitedly. In tears, I ran up on
the stage, "Oh, Robby!  9  did you do it?".
     "Well, Miss Green…remember I told you my mom was sick? Well, actually she had cancer and died this
morning. And well…she was born deaf, so tonight was the  10  time she ever heard me play the piano.
I wanted to make it special.

( )1. A. it
( )2. A. with
( )3. A. and
( )4. A. in
( )5. A. come
( )6. A. why
( )7. A. packed
( )8. A. so
( )9. A. Why
( )10. A. good

B. it's
B. for
B. but
B. by
B. to come
B. if
B. was packed
B. such
B. How
B. better

C. that
C. in
C. /
C. to
C. coming
C. when
C. were packed
C. very
C. What
C. best

D. he
D. as
D. so
D. at
D. came
D. how
D. packing
D. quite
D. When
D. worst

查看答案

题型：填空题

临床上去除龋坏组织的标准主要根据

A．洞壁牙体组织的颜色深浅
B．洞壁牙体组织的硬度
C．洞底的位置
D．预计剩余牙体组织的多少
E．患者的敏感程度

查看答案

题型：填空题

综合性学习。（5分）

哥本哈根气候峰会的召开使得发展低碳经济、使用清洁能源成为共识。某班开展“倡导节能减排、践行‘低碳生活’”的主题活动。

①班里决定出一期板报，请你设计两个栏目标题。（2分）

②根据下面一段文字，概括说明什么是“低碳族”。(不超过30字) (3分)

随着灾难大片《2012》热映，“低碳一族”已悄然形成。把家中灯泡换为节能灯，减少收看电视时间，能坐公交就不开车……这些平日里大家都不注意的小事，如今已经有一些人开始关注。

“低碳族”是指：

查看答案

题型：填空题

试评析1922年新学制的指导思想、体系与特点。

查看答案

题型：填空题

从调查对象的范围看，调查研究分为全面调查和（）。

查看答案

更多题库