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Author Topic: Chemistry Help needed!:-(  (Read 13257 times)

Offline hyebyekadal

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Re: Chemistry Help needed!:-(
« Reply #45 on: May 05, 2009, 06:52:52 pm »
guys need help
from oct 2008 2(c)
Suggest why bubbles of gas were not seen immediately in 2.
And the ms says gas dissolves in water. So the gas formed I.e. chlorine dissolves in water??
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Offline esso

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Re: Chemistry Help needed!:-(
« Reply #46 on: May 05, 2009, 10:15:32 pm »
Quote from: hyebyekadal on May 05, 2009, 06:52:52 pm
guys need help
from oct 2008 2(c)
Suggest why bubbles of gas were not seen immediately in 2.
And the ms says gas dissolves in water. So the gas formed I.e. chlorine dissolves in water??


ya i really also want to know
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Offline sanity_master

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Re: Chemistry Help needed!:-(
« Reply #47 on: May 05, 2009, 10:21:40 pm »
well i answered using that answer without understanding it actually.....but there is another REASONABLE answer

Chlorine in a heavy gas (or slightly heavy)...so it took sometime before rising up
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Offline astarmathsandphysics

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Re: Chemistry Help needed!:-(
« Reply #48 on: May 05, 2009, 10:35:05 pm »
The motion of chlorine ions towards the electron is almost random, and each time the hit a molecule they are knocled back and accelerate 35 times slower than hydrogen ions because they are 35 times heavier. Hence on average their speed will be much slower and they will take longer to get to the electrodes.
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Offline AS girl

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Re: Chemistry Help needed!:-(
« Reply #49 on: May 06, 2009, 05:53:16 am »
astarmathsandphysics  and sanity_master=ur answers are perfect but it's not included in marking scheme. Will we get it wrong if we wrote it?? ???
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Offline astarmathsandphysics

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Re: Chemistry Help needed!:-(
« Reply #50 on: May 06, 2009, 07:57:08 am »
They say suggest a reason so you will get the marks.
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Offline sanity_master

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Re: Chemistry Help needed!:-(
« Reply #51 on: May 06, 2009, 09:52:25 am »
in a suggestion question....u will get the mark if the reason is rational :)

so u can answer about being heavy and slow and about dissolving
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Offline Naruto

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Re: Chemistry Help needed!:-(
« Reply #52 on: May 06, 2009, 07:52:02 pm »
Can anyonw tell me
What are antibumping granules? and why are they used in simple distillation?
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Offline Christy

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Re: Chemistry Help needed!:-(
« Reply #53 on: May 06, 2009, 07:59:53 pm »
they are kinda like boiling chips ... they are used to make the boiling of the sol. smooth .. not to allow the sol. to over heat or super heat that kinda thing :D
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Offline twilight

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Re: Chemistry Help needed!:-(
« Reply #54 on: May 06, 2009, 10:59:41 pm »
yup xactly .. and to prevent the chemicals from splashing as they might be harmful
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Offline guru007

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Re: Chemistry Help needed!:-(
« Reply #55 on: May 07, 2009, 07:05:03 am »
Pipette is the most accurate of them all and i think a buerette should be needed for measuring ACID and pipette can also be used.
Measuring cylinder is not used as the range is very small.
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Offline cockyxrocker

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Re: Chemistry Help needed!:-(
« Reply #56 on: May 07, 2009, 09:15:33 am »
electrolysis of concentrated sodium chloride using carbon electrodes
the solution also contained litmus solution

What happened to the colour of solution around cathode
Why did this change take place?

If there is hydorgen produced at the cathode
then why would there be a colour change since hydrogen is a neutral gas...shouldnt it stay green?
I dont get it...
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Offline twilight

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Re: Chemistry Help needed!:-(
« Reply #57 on: May 07, 2009, 07:17:36 pm »
the solution is concentrated i.e. very less water molecules are present
so it is sodium ions that go to the cathode .. not hydrogen bcoz hydrogen is not abundant enough in the solution
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Offline yinyang

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Re: Chemistry Help needed!:-(
« Reply #58 on: May 07, 2009, 08:10:17 pm »
you are wrong twilight in electrolysis the cation which is lower in the reactivity series i.e. hydrogen

concentration only effects which anion goes i.e. chlorine

when chlorine and hydrogen leave sodium hydroxide is left behind which is a base so litmus indicator turns blue.
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Offline godfather93

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Re: Chemistry Help needed!:-(
« Reply #59 on: May 07, 2009, 08:11:18 pm »
ur right yinyang!
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