6．在恒温恒容的容器中进行反应H2S(g) H2(g) + S(g)，若反应物浓度由1mol/L降到0．6mol/L需20s，那么由0．6mol/L降到0．24mol/L，需反应的时间为 ( )
A．等于18s B．等于12s C．大于18s D．小于18s
5．将纯锌片和纯铜片按图方式插入同浓度的稀硫酸
中一段时间，以下叙述正确的是 ( )
A．两烧杯中铜片表面均无气泡产生
B．甲中铜片是正极，乙中铜片是负极
C．两烧杯中溶液的pH均增大
D．甲、乙溶液均变蓝
4．我国十分重视海水资源的综合利用，下列物质不需经化学变化就能从海水中获得的是( )
A．氯、溴、碘 B．钠、镁、铝 C．烧碱、氢气 D．食盐、淡水
3．下列说法正确的是 ( )
A．酸碱中和反应是吸热反应
B．吸热反应不加热就不会发生
C．放热反应不用加热也一定能发生
D．反应是放热还是吸热可以看反应物和生成物所具有的总能量的相对大小
2．有关化学用语正确的是 ( )
A．乙烯的最简式：C2H4
B．乙醇的结构简式：C2H6O
C．NaCl的电子式：
D．乙酸乙酯的分子式：C4H8O2
1．下列叙述正确的是 ( )
A．目前加碘食盐中主要添加的是KIO3
B．日常生活中无水乙醇常用于杀菌消毒
C．绿色食品是不含任何化学物质的食品
D．在空气质量日报中CO2含量属于空气污染指数
第 二 课 时
48. missed 49. behind 50. fail 51. shame 52. luckily
[书面表达]
One possible version:
Dear David,
Recently we have carried out the suggestion to play music during the class break, and the students have had many private talks about it. Their opinions mainly fall into two groups.
Most of us agree that music should be played. As we know, music can produce a lively and happy atmosphere. Besides, music brings us relaxation after hard study, which reduces the tiredness. Listening to music also makes us feel happy.
On the other hand, some students disagree. In their opinion, they can’t get the expected result from listening to music, as the break between classes is too short. What is needed during the break is peace instead of noise produced by the music. In addition, in class some students are still lost in the music they have heard during the break.
In my opinion, playing some music during the break is necessary, especially after the second period in the morning. And if we play some light music or some pop music that is not so noisy, it will be more popular with us students. Here, I’d like to listen to your opinion.
Yours,
Li Xiang
43. mistaken 44. quite 45. teachers’ 46. allow 47. fond
42. B。广告一中给出了地址：Adams Street”。
[对话填空]
H2(g) + S(g)，若反应物浓度由1mol/L降到0．6mol/L需20s，那么由0．6mol/L降到0．24mol/L，需反应的时间为 ( )
将纯锌片和纯铜片按图方式插入同浓度的稀硫酸