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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 354931 times)

Offline Fastal

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #960 on: May 17, 2010, 09:58:16 am »
drop leaf in boiling water for some time.
take it out and put it in a test tube full of alcohol(in a water bath.
take the leaf out( green colour should be there in the alcohol.
than heat the alcohol in the water bath till only green powder remains.
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6394

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #961 on: May 17, 2010, 09:59:39 am »
n wat it its for dyes like jams n fruits
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6394

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #962 on: May 17, 2010, 10:02:23 am »
Quote from: Fastal on May 17, 2010, 09:58:16 am
drop leaf in boiling water for some time.
take it out and put it in a test tube full of alcohol(in a water bath.
take the leaf out( green colour should be there in the alcohol.
than heat the alcohol in the water bath till only green powder remains.
n so if they ask y step 1 is done
the answer is to extract leaf color
m  i ryt!!!!!
:?
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Offline NidZ- Hero

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #963 on: May 17, 2010, 10:08:04 am »
hw 2 prevent leakage of power 4rom over head pipes
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Offline NidZ- Hero

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #964 on: May 17, 2010, 10:11:16 am »
Quote from: Fastal on May 17, 2010, 09:58:16 am
drop leaf in boiling water for some time.
take it out and put it in a test tube full of alcohol(in a water bath.
take the leaf out( green colour should be there in the alcohol.
than heat the alcohol in the water bath till only green powder remains.
but my teacher told me grind the plant materail in a small amount of water and put into a seperating funnel and add petroleum ther (i was wonderin y ) and shake
chorophyll is extracted into the solvent layer
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Offline mdwael

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #965 on: May 17, 2010, 10:14:37 am »
Oct/nov 2003 Paper 6 chemistry question 5 part D "suggest why conc.sulphuric acid should not be used to dry ammonia" and also in the E part I checked mark scheme answer its says that the mistake correction is "tubes should be evened", explanation " liquid would be transfered to gas jar" can someone explain this to  me I didnt understand what liquid theyre talking about.
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Offline NidZ- Hero

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #966 on: May 17, 2010, 10:15:56 am »
Quote from: 6394 on May 17, 2010, 10:02:23 am
n so if they ask y step 1 is done
the answer is to extract leaf color
m  i ryt!!!!!
:?
but we need 2 extract chorophyll n  this in chem nt bio :)
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Offline NidZ- Hero

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #967 on: May 17, 2010, 10:17:58 am »
Quote from: mdwael on May 17, 2010, 10:14:37 am
Oct/nov 2003 Paper 6 chemistry question 5 part D "suggest why conc.sulphuric acid should not be used to dry ammonia" and also in the E part I checked mark scheme answer its says that the mistake correction is "tubes should be evened", explanation " liquid would be transfered to gas jar" can someone explain this to  me I didnt understand what liquid theyre talking about.
this is becuz de conc. SO4 vil react with ammonia rather den dryin it
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Offline Lariemeeva

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #968 on: May 17, 2010, 10:18:40 am »
Looking through past papers, I noticed there are a lot of questions involving justifications, reasoning and stuff like variables in an experiment etc. that are repeated between years.

Well it's more like the Physics paper 6 where we usually get questions involving justifications, and looking at this topic: https://studentforums.biz/index.php/topic,7496.0.html, it really helped me a lot in solving PP and my real exam, so if there's anyone who can summarize all of those repeated questions that way for chemistry, I'm sure a lot of us here would really find it useful and appreciate it before our exam tomorrow...
« Last Edit: May 17, 2010, 10:22:16 am by Lariemeeva »
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6394

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #969 on: May 17, 2010, 10:20:01 am »
Quote from: Nidzzz on May 17, 2010, 10:15:56 am
but we need 2 extract chorophyll n  this in chem nt bio :)

i noe chem i dnt tak bio evn
i think it shud be crushed n den ..................<i dnt noe den wat>
bt ya i thnk leaf or flowers are supposed 2 be crushed n den do sumthin
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Offline Baladya

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #970 on: May 17, 2010, 10:21:21 am »
Anyone knows a site that explains the three methods of gas delivery?
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Offline mdwael

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #971 on: May 17, 2010, 10:24:10 am »
Quote from: Lariemeeva on May 17, 2010, 10:18:40 am
Looking through past papers, I noticed there are a lot of questions involving justifications, reasoning and stuff like variables in an experiment etc. that are repeated between years.

Well it's more like the Physics paper 6 where we usually get questions involving justifications, and looking at this topic: https://studentforums.biz/index.php/topic,7496.0.html, it really helped me a lot in solving PP and my real exam, so if there's anyone who can summarize all of those repeated questions that way for chemistry, I'm sure a lot of us here would really find it useful and appreciate it before our exam tomorrow...

Yes its so true, I hope someone can make a guide for P6 chemistry like that one for physics...and really fast! :-\
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6394

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #972 on: May 17, 2010, 10:25:07 am »
Quote from: Baladya on May 17, 2010, 10:21:21 am
Anyone knows a site that explains the three methods of gas delivery?
u mn the upward delivery thingy
reply fast mayb i cn help
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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #973 on: May 17, 2010, 10:26:18 am »
Quote from: mdwael on May 17, 2010, 10:24:10 am
Yes its so true, I hope someone can make a guide for P6 chemistry like that one for physics...and really fast! :-\
https://studentforums.biz/index.php/topic,7663.0.html
i made this..
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Offline Kim

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #974 on: May 17, 2010, 10:28:48 am »
Quote from: Baladya on May 17, 2010, 10:21:21 am
Anyone knows a site that explains the three methods of gas delivery?

well i dont know a site but ill tell ya wat they are
UPWARD DELIVERY-FOR GASES LESS DENSE THAN AIR'
DOWNWARD DELIVERY-FOR GASES DENSER THAN AIR
GAS SYRINGE-TO FIND VOLUME OF GAS
COLLECTION OVER WATER-FOR GASES THAT ARE NOT SOLUBLE IN WATER
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