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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: the rael walter white 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 5liter 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 .6X AND NOT .62X when filling out the ice table

Can you show complete ICE table for this problem? A lot depends on what x refers to.

Initial concentration of HI is 0,6 mol / liter, so final concentrations of HI, H_{2} and I_{2} are 0,6  x, 1/2 x and 1/2 x (two molecules of HI produces only one H_{2} and one I_{2}).

Initial concentration of HI is 0,6 mol / liter, so final concentrations of HI, H_{2} and I_{2} are 0,6  x, 1/2 x and 1/2 x (two molecules of HI produces only one H_{2} and one I_{2}).
Or 0.62x, 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.

I totally agree but the solution we were given below confuses the heck out of me

Do you guys think this guy is right or am I just completely lost

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").