交警常用装有重铬酸钾（K2Cr2O7）的仪器检测司机是否酒后驾车，因为酒中的乙醇分子能使橙红色的重铬酸钾变为绿色的物质．在K2Cr2O7中铬（Cr）元素的化合价是_刷题宝

题干

交警常用装有重铬酸钾（K₂Cr₂O₇）的仪器检测司机是否酒后驾车，因为酒中的乙醇分子能使橙红色的重铬酸钾变为绿色的物质．在K₂Cr₂O₇中铬（Cr）元素的化合价是（）

A：+2

B：+3

C：+6

D：+7

上一题下一题 0.0难度选择题更新时间:2020-02-29 08:10:23

答案(点此获取答案解析）

C

同类题1

根据短文理解，选择正确答案。

For Rent

A big apartment for a family of four people. ￥ 2,000 a month. Call Mr. Zhang.

Tel: (010) 8433-9211

Room Wanted

Look for a single（单人的）room under ￥ 650 a month. Please call Carrie at (010) 8433-9236.

Lost

ID card Name:Tracy Number: 232324198804125510

Please call (010) 8838-7166.

For Sale

Come and buy school things!

All kinds of school things!

Soccer ball:￥50 Basketball:￥40 Pen:￥15

Only five days, this week!

Lantian School Things Store, between No. 1 High School and Renmin Hospital

Shop keeper: Mr. White Tel: (010) 8836-7166

同类题2

给下面的字加偏旁组字，再组词

羽 ____ ____ ____ ____

争 ____ ____ ____ ____

次 ____ ____ ____ ____

既 ____ ____ ____ ____

同类题3

None of us had expected the middle-aged engineer died __________ his design uncompleted.

同类题4

现用山核桃的甲（AABB）、乙（aabb）两品种作亲本杂交得F₁，F₁测交结果如下表，下列有关选项不正确的是（　　）

测交类型	测交后代基因型种类及比值
父本	母本	AaBb	Aabb	aaBb	aabb
F₁	乙	1	2	2	2
乙	F₁	1	1	1	1

同类题5

These pictures will show you ________ 50 years ago.

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