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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: SamFisherKappa on October 03, 2016, 11:17:37 AM

Title: Chemical equilibrium problem
Post by: SamFisherKappa on October 03, 2016, 11:17:37 AM

The reversible reaction: H_2(g) + I_2(g) ::equil:: 2HI_(g)
"The system is at equilibrium at a given temperature in a 2 L container. If the system has 0.2 mol of H₂, 0.2 mol of I₂, and 0.6 mol of HI at equilibrium; how many moles of HI should be added to increase the mol number of H₂ to 0.4?"

So far I've worked out that at equilibrium we have 0.1 mol/L for each reactant and 0.3 mol/L for the product. I also know that the reaction shifts to the left since we brake equilibrium by increasing the quantity of HI. Since the molarity of hydrogen doubles by this shift, will the molarity of every other substance double as well?

Title: Re: Chemical equilibrium problem
Post by: AWK on October 03, 2016, 12:12:32 PM

You can check this easily from stoichiometry of reaction.

Title: Re: Chemical equilibrium problem
Post by: Hasanabul on October 03, 2016, 03:57:02 PM

Hi sir, consider that you have added x amount of HI and new equilibrium got established and you got .4 mol of H2. Now as before and after addition temperature remain constant , therefore these two reactions will have same equilibrium constant value.

Title: Re: Chemical equilibrium problem
Post by: SamFisherKappa on October 04, 2016, 08:16:59 AM

Quote from: Hasanabul on October 03, 2016, 03:57:02 PM

Hi sir, consider that you have added x amount of HI and new equilibrium got established and you got .4 mol of H2. Now as before and after addition temperature remain constant , therefore these two reactions will have same equilibrium constant value.

Should have thought of using the constant, I know what to do now. Thank you for your input.