某同学用氯酸钾、二氧化锰为原料,在实验室制取氧气后,将残留物配制成一定质量分数的

题型:实验题

问题:

某同学用氯酸钾、二氧化锰为原料,在实验室制取氧气后,将残留物配制成一定质量分数的氯化钾溶液,方法是先提纯后配制.

(1)提纯氯化钾的实验步骤有:①溶解、②过滤、③蒸发,正确的操作顺序是 _______

(2)操作①、②、③中都用了玻璃棒,在①中用玻璃棒是为了 _________ ,在②中玻璃棒的作用是 _________ ,在③中玻璃棒不断搅拌是为了 _________

(3)若在实验中氯化钾未经干燥直接配制溶液,则溶液中溶质的质量分数 _________ (填“偏大”、“偏小”或“不变”,下同).

(4)若用量筒取水时,俯视液面则所得溶液中溶质的质量分数 _________

考点:溶液的配制粗盐的提纯
题型:实验题

在幼儿语言学习的活动中,永远相伴而存在的是______

A.观和学
B.读和写
C.听和说
D.背和记

题型:实验题
— How was your trip to the ancient village?
— Fantastic! We ______ to a natural museum of strange stones.

A.go
B.went
C.are going
D.wil go
题型:实验题

下列哪项检查对诊断最有帮助

A.血常规

B.尿常规

C.血糖测定

D.T3、T4、TSH测定

E.ACTH兴奋试验

题型:实验题

国家电网公司管理理念是:集团化、集约化、精细化、()。

题型:实验题

(A) 条件(1)充分,但条件(2)不充分.
(B) 条件(2)充分,但条件(1)不充分.
(C) 条件(1)和(2)单独都不充分,但条件(1)和条件(2)联合起来充分.
(D) 条件(1)充分,条件(2)也充分.
(E) 条件(1)和条件(2)单独都不充分,条件(1)和条件(2)联合起来也不充分.

At Company R, the average (arithmetic mean) age of executive employees is 54 years old and the average age of non-executive employees is 32 years old. What is the average age of all the employees at Company R
(1) There are 10 executive employees at Company R.
(2) The number of non-executive employees at Company R is four times the number of executive employees at Company R.

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