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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 373008 times)

nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #660 on: May 14, 2010, 04:29:03 pm »
d) ii) A difference in temp change because of different conc of acid prolly.. cause usually the heat of neutralization is constant for any neutralization.-57kj/mol

e) After an hour it temp will fall back to the initial room temp. that is because the heat will be lost to the surrounding. The mixture will begin to cool

f) greater accuracy could be obtained by using a burette to take measurements.


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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #661 on: May 14, 2010, 04:36:59 pm »
Quote from: nid404 on May 14, 2010, 04:29:03 pm
d) ii) A difference in temp change because of different conc of acid prolly.. cause usually the heat of neutralization is constant for any neutralization.-57kj/mol

e) After an hour it temp will fall back to the initial room temp. that is because the heat will be lost to the surrounding. The mixture will begin to cool

f) greater accuracy could be obtained by using a burette to take measurements.




for d 2 ) the asnweer in past paper is DOUBLING REACTION RELEASES DOUBLE OF ENERGY ..makes any sense to you?
i understood ur answer thx tho

and can you go till g +
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nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #662 on: May 14, 2010, 04:43:21 pm »
okay...doubling reaction? i don't see the reaction being double :-\

anyway

g) 1 shows greater change because total volume of reactants is lesser

H=mcdeltat

mass is proportional to the volume...greater mass, lower Temp change

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nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #663 on: May 14, 2010, 04:46:45 pm »
h) temp change will be lower

heat is contained in a  greater volume of liquid.

Same theory as above
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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #664 on: May 14, 2010, 04:50:08 pm »
I see hmm...i just dont get where the heat goes away to..? the heat is absorbed by the "more " volume of the liqiuid??



By the way ill give u 1+ rep..but after 2 hours cz i just gave some1 :P thx for ur time and help


hmm answr for h) is wrong ... the asnwer is

temp rise is 16 ( double )

explanation : complete neutralisation takes place ..doubling te temp change as exp 1 not all acid was neutralised.. (understandable )
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nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #665 on: May 14, 2010, 04:53:10 pm »
lol...heat doesn't go away...it's just spread over a larger volume. You tell me will a larger volume of water heat faster or a lower volume?
really...then maybe i got the question wrong. If you understood the answer for h, i won't have to go through the whole thing again...lol...sorry...it's just that im doing mechanics alongside...

+rep not really required..but thanks..lol

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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #666 on: May 14, 2010, 04:55:57 pm »
hehe thanks :D  and mechanic  :o :o :o :o :o goodluck
 
and last thing :P

Another questionS

Does NaOH prod. more heat with H2SO4 than wth HCL?
Does Group 1 and group 2 form colourless solution ?
cz i saw an analysis question..A CALCIUM SALT  ( solutrion ) : COLOURLESS . i wrote white..
Why as u increase the length of  an alcohol chain you do not need to burn as much fuel to release the same amoutn of energy?

ill dissapear after this
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nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #667 on: May 14, 2010, 05:01:13 pm »
All neutralization reaction have the same energy released...-57KJ/mol

colorless solutions...?? like what as hydroxides, salts..if salts...which salts.?? calcium carbonate is insoluble

And to your last question...well...i didn't quite get what ur asking...cause does this mean there are more OH groups..or only the no of hydrocarbons increased?

lol u needn't disappear...someone will always help you out here
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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #668 on: May 14, 2010, 05:06:32 pm »
1.ok thats very helpful ..all neut haev same energy release! new fact

anyway

2.yea true ..stupid question from me..not concentrating..hmm i must have read the questing in a wrong way ...nvm

3 u kno the experiment to check which alcohols gives out more energy?

where you put the alcohols in a spirti burner..then heat the water in a copper can  to a specific temperature.. and then weigh the masses of the spirit burner. etc..

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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #669 on: May 14, 2010, 05:08:40 pm »
it says ..solution C has a calcium salt .identify the colour of solution C

does solution mean its colourless?
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nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #670 on: May 14, 2010, 05:12:12 pm »
I gave my igs last year...i don't remember questions like that dude...:P
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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #671 on: May 14, 2010, 05:20:17 pm »
lol

paper 6 ananlysis :P anyway i get it cheers  ::)
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nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #672 on: May 14, 2010, 05:33:27 pm »
lol i meant post the question....cause i don't remember them....if u tell me 'spirit question' im not going to know what u r talkn abt. I don't memorize past papers.. ::)

post the question ill answer
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Offline Baladya

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #673 on: May 14, 2010, 05:43:24 pm »
http://www.freeexampapers.us/IGCSE/Biology/CIE/2006%20Jun/0610_s06_qp_6.pdf

Q3)a)ii) I understand that i have to do proportions, but what should i do next?? draw the woodlice or shade or what??

Thanks ;D
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Offline Fastal

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #674 on: May 14, 2010, 05:49:55 pm »
Quote from: Baladya on May 14, 2010, 05:43:24 pm
http://www.freeexampapers.us/IGCSE/Biology/CIE/2006%20Jun/0610_s06_qp_6.pdf

Q3)a)ii) I understand that i have to do proportions, but what should i do next?? draw the woodlice or shade or what??

Thanks ;D

draw the piechart using this formula
average/total average*360
use this angle and measure the degrrees on the piece chart with a protracter. than label each segment, no shading
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