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Topic: hypochlorite question  (Read 5327 times)

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Offline zetic

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hypochlorite question
« on: December 23, 2014, 12:10:26 PM »
Hi, It is a two part question.

1- I am trying to work out the heat of formation for Calcium Hypochlorite and Sodium Hypochlorite using the following formulas.

a- Cl2 + Ca(OH)2 --> Ca(OCl)2 + CaCl2 + H2O

b- Cl2 + NaOH --> NaCl+NaClO+H2O

Can someone show me how to calculate these step-by-step. I tried to plug in the individual values of each compound but does not seem to be working.

2- I am trying to figure out of is possible to make Sodium Hypochlorite using Sodium Carbonate or Sodium Bicarbonate. Any ideas on this matter would be a great help. Thx!

Tom
« Last Edit: December 29, 2014, 03:20:04 AM by Arkcon »

Offline Borek

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Re: hypochlorite question
« Reply #1 on: December 23, 2014, 12:19:40 PM »
I tried to plug in the individual values of each compound but does not seem to be working.

What values, and into what? Please show details of what you did.
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Offline zetic

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Re: hypochlorite question
« Reply #2 on: December 23, 2014, 09:49:11 PM »
To find heat of formation for Calcium Hypochlorite, I did:

2Cl2 + 2Ca(OH)2 --> Ca(OCl)2 + CaCl2 + 2H2O
With the values of
0 + 2x(-986.09) --> ? + -795.8 + 2x(-285.8)
? = -604.78 , is it correct?

Cl2 + Na(OH) --> NaCl + NaClO + H2O
0 + 2x(-469.15) --> -407.27 + ? + -285.8
? = -245.23, but the energy I found on the internet is -347.3?
« Last Edit: December 29, 2014, 03:20:25 AM by Arkcon »

Offline billnotgatez

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Re: hypochlorite question
« Reply #3 on: December 23, 2014, 11:27:14 PM »
2Cl2 + 2Ca(OH)2  :rarrow: Ca(OCl)2 + CaCl2 + 2H2O

Cl2 + Na(OH)  :rarrow: NaCl + NaClO + H2O

@zetic
I rewrote your equations using the editing features in the posting window
Are they balanced?

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Offline zetic

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Re: hypochlorite question
« Reply #4 on: December 24, 2014, 03:29:46 AM »
@billnotgatez

Thank you for your inputs.
Actually, I think that I made a mistake when writing the sodium hydroxide + chlorine gas equation. However, when I make the calculations, I am aware that is 2 Na(OH) for the reaction, hence, the 2x(-469.15) but which does not give me the same heat of formation for sodium hypochlorite found on the internet of -347.3 (far from it). So, I am wondering if there is anything I am doing wrong in these calculations.
« Last Edit: December 29, 2014, 03:20:42 AM by Arkcon »

Offline zetic

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Re: hypochlorite question
« Reply #5 on: December 24, 2014, 03:42:14 AM »
To others, please give me some insights.

Also, I would like others to comment rather reacting calcium hypochlorite with sodium carbonate as a substitution to form sodium hypochlorite and calcium carbonate can be done. (Perhaps, calcium carbonate will be deposited at the bottom of the beaker when reacted?)

I have looked into finding a way to produce 10% solution of sodium hypochlorite for use, which is not available in my market / electrolysis membrane machines are expensive and chlorine gas is not an option. So, it would be a great help if someone can give me some insights on how to make sodium hypochlorite in a simple solution reaction.

(I have also looking into attempting to modify SDIC or TCCA. Which turns into a much more complex problem.)

Offline unsu

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Re: hypochlorite question
« Reply #6 on: December 24, 2014, 11:46:41 AM »
Hi zetic,

When you are trying to find the unknown enthalpies of formation of Ca(OCl)2 and NaOCl, you need to know the enthalpies of the reactions. That is why you are not getting the right answer.

Offline Borek

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Re: hypochlorite question
« Reply #7 on: December 25, 2014, 04:51:12 AM »
0 + 2x(-469.15) --> -407.27 + ? + -285.8

What are these numbers?

Please pay attention to being precise, you either assume everything is obvious (it isn't) or you not aware it is ambiguous (it is).
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Offline zetic

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Re: hypochlorite question
« Reply #8 on: December 28, 2014, 10:02:43 PM »
@unsu thx for your help. I know i was forgetting something~!
@Borek, you are absolutely right. Will pay close attention in the future

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