白钨矿（主要成分为CaWO4）是一种重要的含钨矿物，CaWO4中钨元素（W）的化合价是_刷题宝

题干

白钨矿（主要成分为CaWO₄）是一种重要的含钨矿物，CaWO₄中钨元素（W）的化合价是（）

A：+6

B：+4

C：+2

D：﹣2

上一题下一题 0.0难度选择题更新时间:2020-04-06 11:47:09

答案(点此获取答案解析）

A

同类题1

There sat an old man in a black coat, his head in his hands thinking.

同类题2

九年级学生高某因沉迷于网络游戏，学习成绩严重下降，在老师和家长的严厉批评、引导下，产生了戒掉“网瘾”的愿望。你认为他戒掉“网瘾”的有效方法有（）

①认清“网瘾”危害，自觉接受家长监督

②培养坚强意志，自觉抵制不良诱惑

③未成年人自控能力较差，应该自觉远离网络

④积极参与健康有益的文化活动，培养高雅情趣

同类题3

绘制生物图时，以下叙述正确的是（）

同类题4

A: Hello, sir, may I talk with you in English?
B: Of course.
A: I have learned English at school for one year. I have very few chances to talk with the English-speaking people.____
B: Oh, you speak English very well.
A: Thank you. By the way, ____
B: No, I’m not. ____
A: How long have you been in this city?
B: ____
A: I see. Do you like this city?
B:Yes. I like it very much. It’s a beautiful city.
A: Thank you.____

A. are you a student from America?
B. So I want to practice English.
C. I’ve lived here since three weeks ago.
D. I’m a student from Australia.
E. I’m glad you like it.

同类题5

.t℃，碳和水在密闭容器中发生下列反应：C(s)+H₂O(g)

CO(g)+H₂(g)，CO(g)+H₂O(g)

CO₂(g)+H₂(g) 当反应达平衡时，测得c(H₂)=1.9 kJ·mol^-1，c(CO)="0.1" kJ·mol^-1，则CO₂的浓度为

小学学科试题库

初中学科试题库

高中学科试题库