【单选题】What’s the tough decision that many students have to make before an exam?
B.
Whether to cheat or not.
C.
What to do if they fail.
D.
What to do if they succeed.
【简答题】元素属性声明语句中声明的内容包含什么? 元素属性声明中, [ 关键字 ] 的类型包含哪些?
【简答题】下列细胞分别属于哪种类型A. 肝细胞属于B. 呼吸道被膜细胞属于C. 骨骼肌细胞属于
【单选题】二氧化氯(ClO 2 )是一种黄绿色易溶于水的气体,常用作饮用水消毒。实验室通过如下过程制备二氧化氯。下列说法正确的是
A.
电解时发生反应的离子方程式为:NH 4 + +3Cl - 2H 2 ↑+NCl 3
B.
溶液X中大量存在的阴离子有Cl - 、OH -
【简答题】洪灾过后,饮用水的消毒杀菌成为抑制大规模传染性疾病爆发的有效方法之一。漂白粉是常用的消毒剂。根据所学知识,回答下列问题: ⑴工业上将氯气通入石灰乳制取漂白粉,反应的化学反应方程式为 ;漂白粉有效成分为(填名称) ;瓶装漂白粉久置空气中会呈稀粥状而失效,试用化学方程式表示失效的原因 。 (2)某化学兴趣小组为了探究HClO的漂白性,设计了如下的实验。 a.通入Cl 2 后,从集气瓶A、B的现象可得出...
【简答题】How do people think about money? There is a truth that many people value money too highly. They think money is all and believe that “money is a passport to anything”. So they can do anything, even imm...
【单选题】What’s the tough decision that many students have to make before an exam?
B.
Whether to cheat or not.
C.
What to do if they fail.