Qualification > Sciences
CHEM AND BIO HELP AND TIPS HERE
rameeziiii:
umm...no more questions?
Vin:
--- Quote from: 7ooD on June 07, 2010, 01:45:51 am ---i have urgent question in 2004 may june q 4 b iii i dnt get it at all and same paper 7 b (ii) in ms they rounded the 0.125 to 0.1 suppose it waz cuz they gave masses to 1 decimal why they didnt do the same in c (i) and (ii)
--- End quote ---
^^ I'm sorry to say I'm too bored solving this ques. Plus I'm done with chem so I don't really feel like doing it now :P jk
Shazizzzle:
Was the paper easy?
Lariemeeva:
http://freeexampapers.com/IGCSE/Chemistry/CIE/2009%20Jun/0620_s09_qp_3.pdf
Q5b.
I'm completely confused, and it obviously has something to do with stiochiometery which I'm really not good at. Anyone can help?
Raywin:
--- Quote from: Lariemeeva on June 07, 2010, 10:40:28 am ---http://freeexampapers.com/IGCSE/Chemistry/CIE/2009%20Jun/0620_s09_qp_3.pdf
Q5b.
I'm completely confused, and it obviously has something to do with stiochiometery which I'm really not good at. Anyone can help?
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This has been discussed a lot before.. :P BUT, here it is :
"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
:D
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