57. They won’t buy new clothes because they__money to buy a color TV set.
A. save B. are saving C. has saved D. were saving
56. - Why? Tom, your shirt is so dirty!
- Mum, I _____ my storeroom downstairs。
A. cleaned B. have worked C. was cleaning D. have been cleaning
55. - I’m sorry, but I shouldn’t have been so rude to you.
- You _____ your temper but that’s OK.
A. have lost B. had lost C. did lose D. were losing
54. - It is said that another new car factory _____ now.
- Yeah. It _____ one and a half years.
A. is building; takes B. is being built; will take
C. is built; will take D. is being built; takes
53. He will stop showing off, if no notice _____ of him.
A. is taken B. will be taken C. takes D. has taken
52. - We _____ that you would fix the TV set this week.
- I’m sorry. I __ to, but I’ve been too busy.
A. had expected; had intended B. are expecting; had intended
C. expect; intend D. expected; intend
2、 硫酸根离子的检验(干扰离子可能有:CO32-、SO32-、SiO32-、Ag+、PO43-等离子):
待测液澄清液白色沉淀(说明待测液中含有SO42-离子)
[针对性训练]
甲、乙、丙三学生各设计了一个实验,结果各自都认为自己所检测的试样中含有SO42-离子。
(1)甲实验为:
试样A的无色溶液白色沉淀沉淀不溶解。
乙认为甲的实验不严谨,因为试样A中若含有 离子(仅填一种),也会有此现象。
(2)乙实验为:
试样B的无色溶液白色沉淀沉淀不溶解。
丙认为乙的实验也不严谨,因为试样B中若含有 离子(仅填一种),也会有此现象。
(3)丙实验为:
试样C的无色溶液现象I现象II。
若丙方案实验后公认为合理,则回答:试剂I是 ,实验中必须加至 ,此时的现象I是 ;试剂II是 ,此时的现象II是 。
1、硫酸的用途:制过磷酸钙、硫酸铵、硫酸铜、硫酸亚铁、医药、炸药,用于铅蓄电池,作干燥剂、制挥发性酸、作脱水剂和催化剂等。
3、用含FeS278%的硫铁矿制硫酸,若煅烧时,损失6%的硫,二氧化硫氧化成三氧化硫时损失2%的硫。要制取1t98%的浓硫酸,需这种硫铁矿 t。
3、环境污染和环境保护:
(1)环境污染:_________ _________ _________ ___________等。
(2)工业“三废”:___________ ____________ ______________。
[针对性训练]
1、接触法制硫酸时,二氧化硫在接触室中钒触媒的作用下,被空气中的氧气氧化而发生反应:2SO2(g)+ O2(g) 2SO3(g);=-1965kJ/mol,接触室的适宜温度为 。其理由是 。
工业上并未采用加压的措施来提高二氧化硫的产率,其理由是
。
2、在硫酸工业制法中,下列生产操作与说明生产操作的主要原因二者都是正确的是( )
A、硫铁矿燃烧前需要粉碎,因为大块的硫铁矿不能在空气中燃烧
B、从沸腾炉出来的炉气需净化,因为炉气中二氧化硫会与杂质反应
C、二氧化硫氧化为三氧化硫时需使用催化剂,这样可以提高二氧化硫的转化率
D、三氧化硫用98.3%的浓硫酸吸收,目的是防止形成酸雾,以便使三氧化硫吸收完全
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