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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 356886 times)

Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2625 on: June 05, 2010, 03:42:35 pm »
Quote from: Ari Ben Canaan on June 05, 2010, 03:40:05 pm
LOOK

Hmm, I don't think you can just add 2- in the chloride ion.  You need to copy the chloride ion twice, and put 1- each time I think.
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elemis

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2626 on: June 05, 2010, 03:46:31 pm »
Quote from: Ivo on June 05, 2010, 03:42:35 pm
Hmm, I don't think you can just add 2- in the chloride ion.  You need to copy the chloride ion twice, and put 1- each time I think.

It just struck me too. I'll edit it. Thanks for pointing it out.
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2627 on: June 05, 2010, 03:50:48 pm »
You can add "2" in front of the chloride ion, and put a "-" above it. That would do too.
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Offline Raywin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2628 on: June 05, 2010, 03:50:55 pm »
Quote from: Ari Ben Canaan on June 05, 2010, 03:41:59 pm
@Raywin

Look above your post.

Yep, saw tht aft i posted my comment.. :P Thx a lot, By the way.. :D
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Offline 7ooD

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2629 on: June 05, 2010, 05:56:28 pm »
i have this doubt in november 2007 5 iii can a strong base replace a weaker one from itz salt solution and another doubt in 2009 may 8 iii in the mark scheme it said NOT SODIUM ,LEAD OR ANY THING BELOW MAGNESIUM how come i dnt get it
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Offline Meticulous

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2630 on: June 05, 2010, 05:59:42 pm »
EVERYBODY +REP NID! SHE IS THE ONE WHO STARTED THIS THREAD! PLUS HE WAS THE ONE HELPING THE MOST!

SHE HELPED ALL OF US IN BIO & CHEMISTRY, ALL BOARDS AND ALL LEVELS!
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Offline polltery

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2631 on: June 05, 2010, 06:11:37 pm »
need help here! :S :(
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nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2632 on: June 05, 2010, 06:16:40 pm »
check the attachment
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Offline polltery

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2633 on: June 05, 2010, 06:21:43 pm »
phew! Thanks!  :D
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nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2634 on: June 05, 2010, 06:24:25 pm »
Quote from: ~ A.F ~ on June 05, 2010, 05:59:42 pm
EVERYBODY +REP NID! SHE IS THE ONE WHO STARTED THIS THREAD! PLUS HE WAS THE ONE HELPING THE MOST!

SHE HELPED ALL OF US IN BIO & CHEMISTRY, ALL BOARDS AND ALL LEVELS!

lol...Why all this? <3

God Bless you A.F <3 :)

Just pray for all of us giving our exams here...that's more than enough :)
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Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2635 on: June 05, 2010, 06:32:13 pm »
Quote from: 7ooD on June 05, 2010, 05:56:28 pm
i have this doubt in november 2007 5 iii can a strong base replace a weaker one from itz salt solution and another doubt in 2009 may 8 iii in the mark scheme it said NOT SODIUM ,LEAD OR ANY THING BELOW MAGNESIUM how come i dnt get it

Sorry, I didn't get your first question. The question (b) is not about it, right? Can you give an example? :-[

About the second. The reason behind choosing any metal below Mg is that Sodium and Lead (also metals abv. Mg) don't react with alkenes. The acrylic acid contains a double bond (is unsaturated).
« Last Edit: June 05, 2010, 06:34:01 pm by ~VIN1094~ »
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Offline Baladya

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2636 on: June 05, 2010, 06:53:07 pm »
VIIIIN U got Member of the month ;D
omg i was sure u would get it :D

and yes, Nid deserves it :D
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Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2637 on: June 05, 2010, 07:14:54 pm »
Such a big thing! Yes she deserves it totally..*ahem a typo :P*

Thanks Baladya.. ;D
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2638 on: June 05, 2010, 07:19:07 pm »
This is a probably a really dumb doubt but I'd appreciate if someone could please kindly answer it.

I'd just like to know in an electrochemical cell, when the more reactive metal loses the electrons and becomes a positive ion, I just wonder why here it becomes the negative cathode.  And the less reactive metal gains the electrons becomes the positive anode?
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Offline 7ooD

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2639 on: June 05, 2010, 07:28:52 pm »
thx vin so anything above mg doesnt react wiz double bonds like alkenes but can u explain reason for that plz and for other question i meant q 5 c iii nov 07 just one more last thing can anyone upload a guide for finding limiting reagent from equation :D
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