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[Chem] Separation

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Separation

想請問下2013年 paper 2 呢條past paper,
點解一定要用 liquid-liquid extraction ge?
3樣野boiling point差咁遠, 點解唔可以就咁用fractional distillation一齊heat, 結果都係hex-1-ene會出先?



其實用咩準則決定要用呢個方法, 而又唔可以用 普通 or fractional distillation 呢?

Million thanks!
   

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其實你見條題目4分,都知唔應該答fractional distillation,因為你只會答到1-2個point,要答liquid liquid extraction先答到4個point......

至於實際上點解我都唔清楚

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there is a major difference between 2 methods - heating which will burn the flammable alkane / alkene
liquid liquid extraction avoids it

p.s. harry is right, amount of marks given is everything

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引用:
原帖由 firoazen 於 2016-1-15 10:31 PM 發表
there is a major difference between 2 methods - heating which will burn the flammable alkane / alkene
liquid liquid extraction avoids it

p.s. harry is right, amount of marks given is everything
Thanks
但個marking最後都係要做fractional distillation on hex-1-ene and octane,
如果好似你咁講咪都都會燒左 hex-1-ene and octane?

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Water is polar --> immersible with organic matter

Fractional distillation helps to separate organic mixture which boiling points are greater than certain difference.

I seldom heard of something called burned away in fractional distillation, if you do not burn and vaporize the liquid until reaching the boiling point, how can it become gas and liquefy in cooler compartment and be being extracted?

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temperature difference is not large engouh to seperate octane and water.

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thx for sharing

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