试题与答案

下列化学方程式书写正确且符合题意的是( ) A.细铁丝在氧气中燃烧--4Fe+3

题型:选择题

题目:

下列化学方程式书写正确且符合题意的是(  )

A.细铁丝在氧气中燃烧--4Fe+3O2

 点燃 
.
 
2Fe2O3

B.试验使用过氧化氢溶液制氧气--2H2O2═2H2O2+O2

C.溶洞的形成--Ca(HCO32

加热
.
.
CaCO3↓+H2O+CO2

D.工业冶炼铁--Fe2O3+3CO

 高温 
.
 
2Fe+3CO2

答案:

A、铁丝在氧气中的燃烧产物是四氧化三铁而不是三氧化二铁,故A错误,

B、实验室制氧气生成的是水和氧气,不是过氧化氢和氧气,故B错误,

C、溶洞的形成实际上是石灰岩中的主要成分碳酸钙遇到溶有二氧化碳的水时,会反应生成溶解性较大的碳酸氢钙,故方程式为:CaCO3+H2O+CO2=Ca(HCO32,故C错误,

D、化学式书写正确,符合质量守恒定律,故D正确,

故选D.

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Tom is a student of Hongqi Middle school. He u______小题1:to be interested in comics about insects. He often borrowed some because he couldn’t a_______小题2:to buy too many comics. Every day he wasted most of his time on these comics and was not patient with h _______小题3:in his study.

One day Tom caught an insect at school and c_______小题4:lots of trouble. To his s_______小题5:, the insect died half an hour later. That night, Tom had a bad dream. He was so t________小题6: of it. Then he went to sleep with his bedroom light o________小题7:.

Tom knew it was the insect’s d_______小题8: that terrified him. Also, Tom found it was necessary for him to p______小题9: attention to his daily studies. Only in this way could he forget that insect. In the e______小题10:, Tom made a decision to change himself.

Now Tom has become one of the best students in his class.

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