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Topic: Iron concentration in a solution... :D  (Read 4076 times)

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Offline steph_r

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Iron concentration in a solution... :D
« on: February 07, 2009, 12:31:47 AM »
Hello budding chemists,
I was wondering whether i could get some assistance with this qsn. I'm not to sure how to write the second equation, where i must include the Fe2O3.
How do i do the decompostition? Help would be greatly appreciated.

A 50.00mL solution with Iron(III) Nitrate has excess NaOH solution added to it, to precipitate Fe(OH)3
After heating, it decomposes to Fe2O3. The mass of precipitate is 0.533g. Calculate the iron concentration in the original solution.
Answer: 0.133M


Here is the equation that i came up with:
Fe(NO3)3 (aq) + 3NaOH (aq)  :rarrow: 3NaNO3 (aq) + Fe(OH)3 (s)

Offline Astrokel

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Re: Iron concentration in a solution... :D
« Reply #1 on: February 07, 2009, 03:33:03 AM »
Quote
After heating, it decomposes to Fe2O3
What do you think has lost from Fe(OH)3 after heating?
No matters what results are waiting for us, it's nothing but the DESTINY!!!!!!!!!!!!

Offline steph_r

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Re: Iron concentration in a solution... :D
« Reply #2 on: February 07, 2009, 03:55:10 AM »
Oxygen? Sorry,i'm not entirely sure  :-\

Offline Borek

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Re: Iron concentration in a solution... :D
« Reply #3 on: February 07, 2009, 04:50:17 AM »
No, not oxygen. Oxygen was part of the liberated molecule though.

Most hydroxdes decompose in the same way when heated.
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Offline steph_r

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Re: Iron concentration in a solution... :D
« Reply #4 on: February 07, 2009, 08:37:07 PM »
Is it just:

Fe(OH)3   :rarrow: Fe2O3 + H2O

Offline enahs

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Re: Iron concentration in a solution... :D
« Reply #5 on: February 07, 2009, 09:35:09 PM »
With proper balancing.

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