Предмет: Химия, автор: isekret00

какой объем этина можно получить из карбида кальция массой 24 г. содержащего посторонние примеси, массовая доля которых составляет 7%?

Ответы

Автор ответа: Аноним
0

Ответ:

Объяснение:

какой объем этина можно получить из карбида кальция массой 24 г. содержащего посторонние примеси, массовая доля которых составляет 7%?

Вычислим  массу  чистого  карбида кальция.   Если доля  примесей 7%, то доля  чистого  вещества  100 - 7 = 93%.

m(CaC2)  =  24× 0,97  = 23,3 г  

Молярная  масса  карбида  кальция  64 г/моль  и  23,3 г  соответствуют 0,364  моль

    0,364 моль                                   0,364 моль

      СаС2  +  2Н2О   =  Са(ОН)2  +  НС≡СН  ↑

   V(C2H2) = 22,4 л/моль  ×  0,364 моль = 8,15 л

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Тема письма: most school children are against wearing a school uniform

Nowadays, people must abide by the dress code is. For example pupils in schools have to go to a school uniform, but students do not like it.
I think that many teens do not like to wear a school uniform. Let me give some reasons for my opinion. To begin with each student would like to have your own style and wearing clothing as he wants. Moreover pupils want to look beautiful, to express their culture through clothes and emotions. And the last but not the least some students against school uniforms because of their religion. For example, someone wearing headgear (scarves) as the national dress, but the school does not provide this clothes and each student must wear a well-defined school uniforms.
But some people believe, that school children must comply with dress code, because when all the kids are dressed in uniforms they feel on par with everyone.More than that school uniform maintains discipline in the school, the children become more responsible and learn to follow the rules. 
It is pity but i don't to share this point of view. I must say that children have the right to choose what kind of clothes they wear to school. We should not prohibit or impose them a certain school uniforms. 
To finish it up, speaking about the aspect I would agree with that idea that some teenagers against school uniforms. 

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