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AS Chemistry- helping each other out!

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Original post by frozo123
what's the enthalpy of hydration? smh

its the enthalpy change when 1 mole of gaseous ions dissolve in water to give a dilute solution. hope this helps! :smile:
Original post by nats927
its the enthalpy change when 1 mole of gaseous ions dissolve in water to give a dilute solution. hope this helps! :smile:


I was testing someone sorry aha
Original post by frozo123
I was testing someone sorry aha

oh aha
Did anyone get FULL MARKS (or close) in the thermal decomposition ISA?
Everyone's doing AQA or OCR :/
Is there anyone doing Edexcel?
If yes, could anyone give me a link for unit 3B notes in pdf format. TIA :biggrin:
Original post by Basma Rahman
Everyone's doing AQA or OCR :/
Is there anyone doing Edexcel?
If yes, could anyone give me a link for unit 3B notes in pdf format. TIA :biggrin:


You can revise unit3B from George Fracer book
Original post by Roflwaffles
You can revise unit3B from George Fracer book


I was thinking to study in my phone so I can carry it anywhere, that's why I was asking for a pdf file ☺ Thanks though!
Original post by Basma Rahman
I was thinking to study in my phone so I can carry it anywhere, that's why I was asking for a pdf file ☺ Thanks though!


I have done edexcel As chemistry so if u have any questions you can message me :smile:
Okay thank you :smile:
Well first, can you please tell me why do we 'heat under reflux'? :colondollar:
Original post by Basma Rahman
Okay thank you :smile:
Well first, can you please tell me why do we 'heat under reflux'? :colondollar:


For what reaction?

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Original post by Basma Rahman
Okay thank you :smile:
Well first, can you please tell me why do we 'heat under reflux'? :colondollar:


It's either because you need to fully oxidise or the reaction is slow or the reactants/products are volatile


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Original post by samb1234
For what reaction?

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In converting am alcohol to a bromoalkane by reacting it with potassium bromide and 50% sulfuric acid to be precise. But a general answer is okay too :smile:
Original post by Basma Rahman
In converting am alcohol to a bromoalkane by reacting it with potassium bromide and 50% sulfuric acid to be precise. But a general answer is okay too :smile:


I think in that reaction you have to create the hbr in situe by reacting the h2so4 with KBr which then reacts with the alcohol to form the bromalkane

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Original post by samb1234
I think in that reaction you have to create the hbr in situe by reacting the h2so4 with KBr which then reacts with the alcohol to form the bromalkane

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Thanks!
Original post by Basma Rahman
Thanks!


Probably ought to check that is right I'm doing edexcel too bit I'm only half way through unit 2 revision. Feel free to ask any other questions

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Original post by C0balt
It's either because you need to fully oxidise or the reaction is slow or the reactants/products are volatile


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Got it ! So it's to speed up the reaction without boiling it off :biggrin: Thanks!
Original post by samb1234
Probably ought to check that is right I'm doing edexcel too bit I'm only half way through unit 2 revision. Feel free to ask any other questions

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Giving exams this May?
Original post by Basma Rahman
Giving exams this May?


Yes I'm taking as this may

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Original post by samb1234
I think in that reaction you have to create the hbr in situe by reacting the h2so4 with KBr which then reacts with the alcohol to form the bromalkane

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That is true but it doesn't explain why reflux is needed.

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Original post by C0balt
That is true but it doesn't explain why reflux is needed.

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As said earlier, because the reaction itself Is slow and volatile, so we need to speed it up without boiling it off.

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