October 15, 2021, 04:59:40 PM
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Topic: Problem with the ICE TABLE  (Read 436 times)

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Offline the rael walter white

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Problem with the ICE TABLE
« on: September 12, 2021, 01:15:39 AM »
For the reaction 2HI -> H2 + I2 (all gas phase) the value of the equilibrium constant at 700K is 0.0183. If 3.0 moles of HI are placed in a 5-liter vessel and allowed to decompose according to the above equation, what percentage of the original HI would remain at equilibrium

Can someone explain why the equilibrium concentration constant for 2HI IS .6-X AND NOT .6-2X when filling out the ice table

Offline Borek

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Re: Problem with the ICE TABLE
« Reply #1 on: September 12, 2021, 03:00:24 AM »
Can you show complete ICE table for this problem? A lot depends on what x refers to.
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Offline Orcio_Dojek

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Re: Problem with the ICE TABLE
« Reply #2 on: September 12, 2021, 07:29:39 AM »
Initial concentration of HI is 0,6 mol / liter, so final concentrations of HI, H2 and I2 are 0,6 - x, 1/2 x and 1/2 x (two molecules of HI produces only one H2 and one I2).

Offline Borek

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Re: Problem with the ICE TABLE
« Reply #3 on: September 12, 2021, 08:31:04 AM »
Initial concentration of HI is 0,6 mol / liter, so final concentrations of HI, H2 and I2 are 0,6 - x, 1/2 x and 1/2 x (two molecules of HI produces only one H2 and one I2).

Or 0.6-2x, x and x, depending on what the x is. Both approaches are OK, it is just about knowing which one you use and what you solve for.
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Offline the rael walter white

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Re: Problem with the ICE TABLE
« Reply #4 on: September 12, 2021, 06:13:05 PM »
I totally agree but the solution we were given below confuses the heck out of me

Offline the rael walter white

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Re: Problem with the ICE TABLE
« Reply #5 on: September 12, 2021, 06:14:33 PM »
Do you guys think this guy is right or am I just completely lost

Offline Borek

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Re: Problem with the ICE TABLE
« Reply #6 on: September 13, 2021, 03:20:27 AM »
Do you guys think this guy is right or am I just completely lost

No, this solution is incorrect and you are perfectly right being confused. Stoichiometric coefficient of 2 is missing (either as just "2" or as "1/2").
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