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Offline cœur_vaillant

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hi, another question
« on: June 03, 2008, 01:36:50 AM »
hey, im having a bit of trouble with this question, if someone could help would be much appreciate. merci!  ;D
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In a series of experiments, a chemist prepared three different compounds that contain only iodine and fluorine and determined the mass of each element in each compound

Compound        mass iodine (g)            mass fluorine (g)

1                         4.75                       3.56

2                         7.64                       3.43

3                         9.41                       9.86



(a) calculate the mass of fluorine per gram of iodine in each compound.
(b) how do the numbers in part (a) support the atomic theory?


Offline tamim83

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Re: hi, another question
« Reply #1 on: June 03, 2008, 09:51:25 AM »
This question is pretty straight foward.  Reread part a, it tells you what to do practically. 

For part b, you need to know the postulates of atomic theory (see http://en.wikipedia.org/wiki/John_Dalton).  Look closely at number 4. 

Good Luck.   ;)

Offline cœur_vaillant

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Re: hi, another question
« Reply #2 on: June 03, 2008, 07:38:24 PM »
well i tried the question and didn't get it (hence why i came on here for help..i did not just post it on here without doing any work).  it may be straightforward for you, but i do not see it as such. so, please be understanding.

Offline macman104

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Re: hi, another question
« Reply #3 on: June 03, 2008, 07:45:17 PM »
Mass of fluorine PER gram of Iodine, the "per gram" indicates division:

mass of fluorine / mass of iodine is mass per gram of iodine.

For the second part tamim has already given you a link and direction on where your next step should be.

Offline tamim83

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Re: hi, another question
« Reply #4 on: June 04, 2008, 09:35:47 AM »
Quote
well i tried the question and didn't get it (hence why i came on here for help..i did not just post it on here without doing any work).  it may be straightforward for you, but i do not see it as such. so, please be understanding.

Sorry, I wasn't trying to be mean or anything.  I usually tell my own students to reread questions that I think are pretty straight forward.  Sometimes a very careful rereading helps a great deal. 

Offline klumba

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Re: hi, another question
« Reply #5 on: November 15, 2009, 07:00:48 PM »
i've got the same problem. I found the numbers but I can't associate it with the atomic theory. It doesn't apply to the law of multiple proportions either. Or..to make it work, I should solve this problem by molar masses. So, I am really confused about b) part.

Offline Borek

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Re: hi, another question
« Reply #6 on: November 16, 2009, 07:46:05 AM »
What are these numbers? (list values)
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Offline klumba

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Re: hi, another question
« Reply #7 on: November 18, 2009, 05:22:40 PM »
0.749 g
0.449 g
1.05 g
does this suppose to support the law of multiple proportions?

Offline Borek

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Re: hi, another question
« Reply #8 on: November 19, 2009, 03:46:31 AM »
Try to find a number so that each number on the list is a multiply of that number.

For example, 0.4, 0.6 and 1.0 are all multiplies of 0.2.
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Offline klumba

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Re: hi, another question
« Reply #9 on: November 19, 2009, 09:37:43 AM »
it should be whole number..unless i find molar masses, there's no way I could get the whole number multiple, what a stupid question it is :)

Offline Borek

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Re: hi, another question
« Reply #10 on: November 19, 2009, 09:48:12 AM »
unless i find molar masses, there's no way I could get the whole number multiple

They all ARE whole multiples of some number and you don't need molar masses to find it out.

Well, at least I did it without using molar masses, so I know it is possible for me  :P
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Offline klumba

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Re: hi, another question
« Reply #11 on: November 19, 2009, 10:37:07 AM »
well...here 0.5 is the possible multiple, but diving .75 by .5 we get 1.5, so...i'm still very confused..

Offline Borek

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Re: hi, another question
« Reply #12 on: November 19, 2009, 10:55:34 AM »
45, 75 & 105 - what is the GCD?
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Offline klumba

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Re: hi, another question
« Reply #13 on: November 19, 2009, 11:19:35 AM »
5...
0.05 would be for my numbers..
but don't they have to be divided by the smallest number among them and by gcd?

Offline Borek

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Re: hi, another question
« Reply #14 on: November 19, 2009, 12:32:40 PM »
No, it is not 5.
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