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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 333091 times)

Offline igext

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2925 on: June 06, 2010, 05:23:39 pm »
Quote from: MasterMath on June 06, 2010, 05:20:31 pm
haber : 450C and 200 atm .. iron as catalyst ( Finely divided)
Contact: 450C 2 atm.. Vanadium (V) oxide
Cracking : Al2O3/SiO2 500C and 10-12atm
for adding H2O to ethene Phosphoric acid 300C 70 atm
For adding H2 to ethene Ni 200C
Correct me if im wrong!
are you quite sure thats all what we need to know?
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Offline 8T

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2926 on: June 06, 2010, 05:24:04 pm »
Quote from: ~VIN1094~ on June 06, 2010, 05:22:42 pm
It;s been solved earlier, i need to look..
Thanks ill be waiting for ur explanation !
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Offline Dana

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2927 on: June 06, 2010, 05:24:11 pm »
Quote from: 8T on June 06, 2010, 04:59:50 pm
Could someone please explain may june 09 paper 32 q 5 b
I know it's for instance K3PO4 or T3 PO4.. but the other 2 marks not quite so any help??
its T3(PO4)2 Since 8 cm3 of Na3PO4 react fully with 12 cm3 of nitrate of T. This means the molar ratio is 12:8 or 3:2
« Last Edit: June 06, 2010, 05:27:21 pm by Dana »
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2928 on: June 06, 2010, 05:25:32 pm »

"the vol. of phosphate soln used in cm3 is half the height of the ppt in mm
also at 8cm3 all the soln is used up. tht is because adding more does not increase the height of the ppt meaning there was no further reaction on adding more.
also the formula is T3(PO4)2-----because

u take it as 12cm3 of T nitrate react with 8cm3 of sodium phosphate (thts wen all the reactants r used up)
so.....12:8...simplify it
12:8
6:4
3:2
and therefore u get T3(PO4)2"

courtesy : mohit
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Offline MasterMath

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2929 on: June 06, 2010, 05:27:27 pm »
Quote from: igext on June 06, 2010, 05:23:39 pm
are you quite sure thats all what we need to know?
Yes .. if there are more ill post .. thats what came up to my mind at za moment :D
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Offline 8T

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2930 on: June 06, 2010, 05:30:50 pm »
Ok thanks much both but i asked for p 32 but i guess its the same thank :)
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Offline Dana

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2931 on: June 06, 2010, 05:32:01 pm »
Quote from: 8T on June 06, 2010, 05:30:50 pm
Ok thanks much both but i asked for p 32 but i guess its the same thank :)
oh yea that one uses 6 cm3 instead of 8 but its the same method yes. you're welcomee :)
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2932 on: June 06, 2010, 05:32:18 pm »
Quote from: 8T on June 06, 2010, 05:30:50 pm
Ok thanks much both but i asked for p 32 but i guess its the same thank :)
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Offline Dana

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2933 on: June 06, 2010, 05:33:21 pm »
Quote from: MasterMath on June 06, 2010, 05:27:27 pm
Yes .. if there are more ill post .. thats what came up to my mind at za moment :D
dude, you sure we gotta learn ALL of that?! I've done lots of past papers and they've only ever asked for conditions for the contact and haber process :S
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elemis

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2934 on: June 06, 2010, 05:34:38 pm »
Quote from: Dana on June 06, 2010, 05:33:21 pm
dude, you sure we gotta learn ALL of that?! I've done lot's of past papers and they've only ever asked for conditions for the contact and haber process :S

What papers have you been doing :o This comes up ALL THE TIME !!

Are you core or extended ?
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Offline MasterMath

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2935 on: June 06, 2010, 05:35:24 pm »
Quote from: Dana on June 06, 2010, 05:33:21 pm
dude, you sure we gotta learn ALL of that?! I've done lots of past papers and they've only ever asked for conditions for the contact and haber process :S
lol , haber comes oftenly along with contact .. but for the cracking i think you dont need to know what i typed until AS .. you can get the mark by stating heat and catalyst..
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Offline MasterMath

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2936 on: June 06, 2010, 05:36:36 pm »
Quote from: Ari Ben Canaan on June 06, 2010, 05:34:38 pm
What papers have you been doing :o This comes up ALL THE TIME !!

Are you core or extended ?
She means shes seen on contact and haber .. not that she never saw them.. read her post slowly :P
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Offline J.Darren

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2937 on: June 06, 2010, 05:37:43 pm »
Quote from: MasterMath on June 06, 2010, 05:35:24 pm
lol , haber comes oftenly along with contact .. but for the cracking i think you dont need to know what i typed until AS .. you can get the mark by stating heat and catalyst..
Silicon (IV) oxide / Aluminium oxide catalyst to be exact ...
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Offline MasterMath

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2938 on: June 06, 2010, 05:38:48 pm »
Quote from: J.Darren on June 06, 2010, 05:37:43 pm
Silicon (IV) oxide / Aluminium oxide catalyst to be exact ...
Ive said that :P look at my post before
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Offline Dana

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2939 on: June 06, 2010, 05:40:05 pm »
Quote from: MasterMath on June 06, 2010, 05:36:36 pm
She means shes seen on contact and haber .. not that she never saw them.. read her post slowly :P
thanks xD
so we need to know the exact conditions for only haber, contact and..cracking?
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