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Topic: molar enthalpy of combustion of acetone next step?  (Read 32142 times)

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Offline ARGOS++

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Re: molar enthalpy of combustion of acetone next step?
« Reply #15 on: March 07, 2008, 05:34:05 PM »
Dear Frederick95;

I got quite close the same, if , if I divide YOUR result by 1000!, but for how many Moles Acetone, and that’s how many Grams?

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Offline Frederick95

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Re: molar enthalpy of combustion of acetone next step?
« Reply #16 on: March 07, 2008, 05:40:58 PM »
I got 0.0015 mol C3H6O(acetone) as an answer. But what to do with this?

Offline ARGOS++

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Re: molar enthalpy of combustion of acetone next step?
« Reply #17 on: March 07, 2008, 05:46:38 PM »

Dear Frederick95;

You got Q, but you need Q per Mole, also Q / Mole!
(Use at least 2 figures more!! You can round your end result, - Not before!)


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Offline Frederick95

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Re: molar enthalpy of combustion of acetone next step?
« Reply #18 on: March 07, 2008, 05:51:46 PM »
AHA!! SO....

2317.5 / 0.0015 mol C3H6O

= 1545000 J?

Offline ARGOS++

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Re: molar enthalpy of combustion of acetone next step?
« Reply #19 on: March 07, 2008, 05:59:07 PM »

Dear Frederick95;

NO!,  –   I told you:  Use at least 2 figures more!!

That will give you:  H =  - 1462.6  kJoules / mole for Acetone.

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Offline Frederick95

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Re: molar enthalpy of combustion of acetone next step?
« Reply #20 on: March 07, 2008, 06:01:08 PM »
1462.6  kJoules?

But why not 2317.5 kJ?

Offline ARGOS++

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Re: molar enthalpy of combustion of acetone next step?
« Reply #21 on: March 07, 2008, 06:03:28 PM »

Dear Frederick95;

Why should it?

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Offline Frederick95

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Re: molar enthalpy of combustion of acetone next step?
« Reply #22 on: March 07, 2008, 06:05:16 PM »
Because 2317.5 kJ is the value we got for q

1462.5 does not = q

Offline ARGOS++

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Re: molar enthalpy of combustion of acetone next step?
« Reply #23 on: March 07, 2008, 06:17:32 PM »

Dear Frederick95;

Please read correct:   H- 1462.6  kJoules / mole for Acetone.
(That's a little more precise = 2.320 kJoules / 0.001586 moles.)

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                    ARGOS++


Offline Frederick95

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Re: molar enthalpy of combustion of acetone next step?
« Reply #24 on: March 07, 2008, 06:30:25 PM »
OHHHH! :D


So Enthalpy = 2.320 kJoules / 0.001586 moles

Therefore Enthalpy(H) is 1462 kJ/mol?

Offline ARGOS++

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Re: molar enthalpy of combustion of acetone next step?
« Reply #25 on: March 07, 2008, 06:34:40 PM »

Dear Frederick95;

Don’t miss the Sign, as you told in your Question!

Quote
      H = - Q = - 455 J = -0.455 kJ
     Number of moles (n) = (given mass (g))/(gram-formula mass)

Good Luck!
                    ARGOS++


Offline Frederick95

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Re: molar enthalpy of combustion of acetone next step?
« Reply #26 on: March 07, 2008, 06:36:10 PM »
Enthalpy -1462 kJ/mol (because it is exothermic)?

Offline ARGOS++

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Re: molar enthalpy of combustion of acetone next step?
« Reply #27 on: March 07, 2008, 06:39:45 PM »

Dear Frederick95;

Precisely!

Good Luck!
                    ARGOS++

Offline Frederick95

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Re: molar enthalpy of combustion of acetone next step?
« Reply #28 on: March 07, 2008, 06:41:00 PM »
THANK YOU ARGO YOU ARE THE BEST!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :) :) :) :) :) :) ;D ;D ;D ;D :D :D :D :D :D

I will not forget you!!!:):)


Offline ARGOS++

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Re: molar enthalpy of combustion of acetone next step?
« Reply #29 on: March 07, 2008, 06:46:32 PM »

Dear Frederick95;

You’re welcome!   ─   Soon (but not toooo soon!) again.


Good Luck!
                    ARGOS++


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