Author Topic: IG Chemistry Paper 3 discussion  (Read 24324 times)

Offline a7medokool

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Re: IG Chemistry Paper 3 discussion
« Reply #120 on: June 02, 2009, 11:51:39 am »
Hey guys for the empircal formula Question
u dividde the percentage by the RMM right i got 1.5 for mg i dont remember for the other element but if u get 1.5 is it times both by 2?

Offline sweetie

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Re: IG Chemistry Paper 3 discussion
« Reply #121 on: June 02, 2009, 12:02:42 pm »
oh
i got Mg3N2
by da way, which was in excess?
and wa was the no. of moles??????

Offline IGCSE nightmare

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #122 on: June 02, 2009, 12:03:30 pm »
What makes you so sure ?!?
By the way I wrote that too but many are saying it's T3PO4

Offline qwert101

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #123 on: June 02, 2009, 12:04:59 pm »
I am so curious to find out the answers so pls answer my following questions:

1 What was the formulae of the metal T?n how to do that

2 What will be (needed to produce/produced by the hydrolysis) of the ester
(where the 2 blanks were given)

3 What was the test to show that both lactic acid and acrylic acid contained the COOH group

I hope i'll get the answers soon
Thanx.


1. T3(PO4)2
2. i wrote Alkyl n alcohol
3. litmus ppr. turns BLUE litmus RED


litmus is an indicator ;)

zara

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Re: IG Chemistry Paper 3 discussion
« Reply #124 on: June 02, 2009, 12:10:22 pm »
Fluorine was in excess and silicon was the limitin reagent....
0.08 was the no of moles....cz the product is the same as dat of the limitin agent...dats wat i read in the txt bk...

Offline Kim

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #125 on: June 02, 2009, 12:10:26 pm »
What makes you so sure ?!?
By the way I wrote that too but many are saying it's T3PO4
believe me none of us are sure of our answers and dont worry I m sure we all will get marks that question was like wat 3 martks?so i m sure they will giv us 2 for nearly gettin our answers!!!!!!!!!!!!!!!!!!!!!!!!hehehe
After all is said and done, more is said than done.

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Offline sweetie

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #126 on: June 02, 2009, 12:21:37 pm »
wa did u rite 4 da properties of Cao
i rote 1) it is basic
        2)it is soluble in water
and 4 the excess que. i got flourine
do u think mi answers r rite??????????????????
« Last Edit: June 02, 2009, 12:26:59 pm by notty_me »

Offline xTremep

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #127 on: June 02, 2009, 12:22:40 pm »
1-WASHING THE PRECIPtate to remove impurities and get pure salt
2-heating in an oven to evaporate water and drying the salt
3-t3po4, because 18.0cm3 of T completely reacted with 6.0cm3 of po4 (from graph) there fore 18 is three times 6 .................
4-last page
i-the emperical formulae was Mg3N2
ii-silicon was limiting reagent
iii-0.08 moles


This is what i wrote exactly :) hope its correct

Offline sweetie

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Re: IG Chemistry Paper 3 discussion
« Reply #128 on: June 02, 2009, 12:23:42 pm »
was da qus bout the one in excess or da limiting reagent????????????

Offline mr3bood

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Re: IG Chemistry Paper 3 discussion
« Reply #129 on: June 02, 2009, 12:25:48 pm »
"Fluorine was in excess and silicon was the limitin reagent....
0.08 was the no of moles....cz the product is the same as dat of the limitin agent...dats wat i read in the txt bk..."

Yup!..i wrote silicon was the limiting reagent...........and for the very last question...i wrote 0.09 moles...!....hope its right...

I totally screwed up my exam!!....i think i'm going down to a C/D now...

Offline Kim

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #130 on: June 02, 2009, 12:32:26 pm »
1-WASHING THE PRECIPtate to remove impurities and get pure salt
2-heating in an oven to evaporate water and drying the salt
3-t3po4, because 18.0cm3 of T completely reacted with 6.0cm3 of po4 (from graph) there fore 18 is three times 6 .................
4-last page
i-the emperical formulae was Mg3N2
ii-silicon was limiting reagent
iii-0.08 moles


This is what i wrote exactly :) hope its correct
my moles was soo wrong
i got 0.095
cause i divided the value of f2 by 2
anyways themg2n3 taht is wrong cause u see after u get that u have to divide the values by the smallest which means 3/2=1.5=2 and 2/2=1 so the formuls mg2n(2 because u take the whole number)
After all is said and done, more is said than done.

By the time a man realizes that maybe his father was right, he usually has a son who thinks he’s wrong.

The early bird may get the worm, but the second mouse gets the cheese.

zara

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Re: IG Chemistry Paper 3 discussion
« Reply #131 on: June 02, 2009, 12:33:45 pm »
the ques was about the limiting reagent....
n 0.09 moles is nt rite....its 0.08 moles...
i messed up in the T metal thing...maybe also abt chloropyll....i rote the answer but not sure abt it....

Offline sweetie

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Re: IG Chemistry Paper 3 discussion
« Reply #132 on: June 02, 2009, 12:34:03 pm »
oops, i  only rote dat flourine was in excess >:(  any problem???

wa did u ppl rite in da 2 blanks?????
i rote carboxyl & hydroxyl
do u think it s rite? ??? :(  :-\
« Last Edit: June 02, 2009, 12:36:53 pm by notty_me »

zara

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Re: IG Chemistry Paper 3 discussion
« Reply #133 on: June 02, 2009, 12:35:20 pm »
the two blanks abt the acrylic acid??
well the answer was lactic acid and water

Offline Kim

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Re: IG Chemistry Paper 3 discussion
« Reply #134 on: June 02, 2009, 12:36:38 pm »
i messed up in the moles the last part only luckily but u never know how much more i have messed up
and in the blanks i wrote acid and alcohol group
After all is said and done, more is said than done.

By the time a man realizes that maybe his father was right, he usually has a son who thinks he’s wrong.

The early bird may get the worm, but the second mouse gets the cheese.