Author Topic: Chemistry...  (Read 4050 times)

Offline ~~~~shreyapril~~~~

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Chemistry...
« on: September 03, 2009, 10:13:31 am »
I need chem notes on moles that is stoichiometry and carbon chemistry..
these would help me n my mocks..
any sites would also serve my needs
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Offline Ghost Of Highbury

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Re: Chemistry...
« Reply #1 on: September 03, 2009, 10:19:33 am »
find 'em attached
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Offline ~~~~shreyapril~~~~

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Re: Chemistry...
« Reply #2 on: September 03, 2009, 10:21:11 am »
thanx mann
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Offline Ghost Of Highbury

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Re: Chemistry...
« Reply #3 on: September 03, 2009, 10:39:20 am »
anytime...
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Q80BOY

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Re: Chemistry...
« Reply #4 on: September 03, 2009, 01:21:36 pm »
gr8 job adi .. keep it up !!  ;)

Offline Ghost Of Highbury

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Re: Chemistry...
« Reply #5 on: September 04, 2009, 05:15:54 pm »
hey tks Q80
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Offline ~~~~shreyapril~~~~

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Re: Chemistry...
« Reply #6 on: September 07, 2009, 03:55:34 am »
wat is the empirical formula of a comoud weighing 60g
whic has 20g content oxygen
and other hydrogen..
i am gettign a weird ans
pls help
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Offline Ghost Of Highbury

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Re: Chemistry...
« Reply #7 on: September 07, 2009, 07:33:42 am »
maybe because its a wierd question...

                       H           O

mass               40g        20g

molar mass        1           16

(x)mass/mm      40           1.25

x/least             40/1.25      1

ratio                  32            1

H32O

---this compound cannot exist-----

plzz check the question
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Offline slvri

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Re: Chemistry...
« Reply #8 on: September 07, 2009, 10:46:06 am »
maybe because its a wierd question...

                       H           O

mass               40g        20g

molar mass        1           16

(x)mass/mm      40           1.25

x/least             40/1.25      1

ratio                  32            1

H32O

---this compound cannot exist-----

plzz check the question
H32O........LOOOOOOOOOOOL :P :P :P
i hate A level...........

Offline Ghost Of Highbury

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Re: Chemistry...
« Reply #9 on: September 07, 2009, 10:47:02 am »
wat answer r u getting..slvri?
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Offline slvri

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Re: Chemistry...
« Reply #10 on: September 07, 2009, 10:50:12 am »
wat answer r u getting..slvri?
same as the one ur getting.........definitely some problem in da question
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nid404

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Re: Chemistry...
« Reply #11 on: September 07, 2009, 04:17:58 pm »


ok so

40g H and 20g O

WHat you first do is find out % composition of each

so
                                    H                            O
% composition           40/60*100                20/60*100
ratio of compostion           2               :            1

It's H2O


That's how you do empirical formula for this one i guess

Offline Ghost Of Highbury

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Re: Chemistry...
« Reply #12 on: September 07, 2009, 04:20:48 pm »
dont u do it by the mass method...???

can u plz spot the error in the steps i rote...
« Last Edit: September 07, 2009, 04:23:25 pm by eddie_adi619 »
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Offline slvri

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Re: Chemistry...
« Reply #13 on: September 07, 2009, 04:34:12 pm »


ok so

40g H and 20g O

WHat you first do is find out % composition of each

so
                                    H                            O
% composition           40/60*100                20/60*100
ratio of compostion           2               :            1

It's H2O


That's how you do empirical formula for this one i guess
but hows that possible???? i mean u found percentage composition by mass but thats not necessarily the same as the empirical formula(number of moles of atoms of each element)
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Offline Ghost Of Highbury

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Re: Chemistry...
« Reply #14 on: September 07, 2009, 04:49:37 pm »


ok so

40g H and 20g O

WHat you first do is find out % composition of each

so
                                    H                            O
% composition           40/60*100                20/60*100
ratio of compostion           2               :            1

It's H2O


That's how you do empirical formula for this one i guess
but hows that possible???? i mean u found percentage composition by mass but thats not necessarily the same as the empirical formula(number of moles of atoms of each element)
true..
u didnt divide it by the molar mass
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