【单选题】阿伏加德罗常数约为6.02×10 23 mol?L -1 .下列叙述中正确的是( )
A.
在室温下,8g 甲烷含有的共价键数约为6.02×10 23
B.
3.2g的Cu与足量的浓硝酸反应生成的气体分子数约为6.02×10 23
C.
含有6.02×10 23 个中子的D 2 0的质量为2.0g
D.
pH=2的硫酸氢钠溶液中的硫酸根离子数约为6.02×10 23
【单选题】打火机的燃料是丁烷(化学式为C 4 H 10 ),它燃烧时,火苗高且明亮.下列叙述中正确的是( ) ①丁烷由碳、氢两种元素组成 ②丁烷由丁烷分子构成 ③丁烷分子由碳、氢两个元素构成 ④丁烷由4个碳原子和10个氢原子组成 ⑤丁烷分子由碳原子和氢原子构成 ⑥丁烷由碳和氢两种单质组成.
【多选题】阿伏加德罗常数约为6.02×10 23 mol -1 .下列叙述中正确的是( )
A.
32g含有少量臭氧的氧气中,共含有氧原子数为2×6.02×10 23
B.
200mL1mol/LAl 2 (SO 4 ) 3 溶液中,Al 3+ 和SO 4 2- 离子数的总和是6.02×10 23
C.
5.6g铁粉完全溶于硝酸,失去的电子数介于0.2×6.02×10 23 ~0.3×6.02×10 23 之间
D.
在SiO 2 晶体中,若含有1mol Si原子,则含Si-O键数为2×6.02×10 23
【简答题】阅读理解。 Long, long ago there was no zero. To write the number sixty-three people wrote 63. To write six hundred and three, people wrote 63. The space between six and three was there to mean.' not any'te...
【单选题】Why do few men take a long parental leave?
A.
A long leave will have a negative impact on their career.
B.
They just have too many responsibilities to fulfill at work.
C.
The economic loss will be too much for their family to bear.
D.
They are likely to get fired if absent from work for too long.
【单选题】MOH和ROH两种一元碱的溶液分别加水稀释时,pH变化如图所示.下列叙述中正确的是( )
【单选题】.下列叙述中正确的是( )
A.
等质量的O 2 、O 3 中所含氧原子个数之比为2:3
B.
标准状况下,体积相等的CCl 4 和Cl 2 ,前者含有的氯原子数是后者的两倍
C.
1molCO和CH 4 的混合气体所含的碳原子数和1molCO 2 所含的碳原子数相等
D.
10g NH 3 中含有原子数目约为4×6.02×10 23
【简答题】2016五年级暑假学习生活英语答案第63页暑假即将开始啊,不要忘记做暑假作业啊,求2016五年级暑假学习生活英语答案第63页
【单选题】We mustn't pretend _____ what we don't know. [ ]