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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: raiderhader2 on February 25, 2009, 08:44:15 PM

Title: AP Chemistry:For the following rxn: CO2(g)+H2(g)<-->H2O(g)+CO(g), equilibrium is
Post by: raiderhader2 on February 25, 2009, 08:44:15 PM

achieved at 2000K
Following equilibrium concentrations:
[H2]=0.20 M
[CO2]=0.30 M
[H2O]=[CO]=0.55M

When the system is cooled from 2000K to a lower temperature, 30.0% of the CO(g) is converted back to CO2(g). Calculate the Kc at this lower temperature.

Here's what I tried:
[CO]=0.55M-(0.55M)(0.3)=0.39M
[H2O]=0.39M
[CO2]=0.30M+90.55M)(0.3)=0.47M
[H2]=0.20M+(0.55M)(0.3M)

Kc=(0.39M)^2/[(O.47M)(0.37M)]=0.87

Title: Re: AP Chemistry:For the following rxn: CO2(g)+H2(g)<-->H2O(g)+CO(g), equilibrium is
Post by: Borek on February 26, 2009, 03:20:31 AM

Quote from: raiderhader2 on February 25, 2009, 08:44:15 PM

[H2O]=0.39M

Seems like you are on the right track, you just missed that water concentration must change as well.

Title: Re: AP Chemistry:For the following rxn: CO2(g)+H2(g)<-->H2O(g)+CO(g), equilibrium is
Post by: Vidya on February 26, 2009, 09:05:46 PM

I think you have calculated right equilibrium concentrations.Your water concentration is also  right.

Title: Re: AP Chemistry:For the following rxn: CO2(g)+H2(g)<-->H2O(g)+CO(g), equilibrium is
Post by: Borek on February 27, 2009, 02:46:55 AM

Quote from: vidya kaushik on February 26, 2009, 09:05:46 PM

I think you have calculated right equilibrium concentrations.Your water concentration is also  right.

Yep. I have misread the solution. My bad.