DougTheMapper
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Registered: 20-7-2008
Location: Michigan, USA
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Calculating Equilibrium Pressure
Hey everyone, I have a question regarding equilibrium pressure.
Consider the following equation:
NaHCO3(aq) + HCl(aq) --> NaCl(aq) + CO2(g) + H2O(l)
Imagine the reaction was conducted inside a sealed, fixed-volume system. How would one go about calculating the pressure at which the gas pressure of
the CO2 would be at equilibrium with the re-formation of NaHCO3 (Or Na2CO3)?
I've so far been unable to figure out how to calculate the equilibrium pressure because I can't find an equation for a aqueous-gas relationship.
I do know enough that it will likely be some pressure higher than the vapor pressure of a saturated mixture of HCl and CO2 dissolved in the water. It
seemed simple enough at first but has grown into a very complicated mess!
Victor Grignard is a methylated spirit.
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gsd
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Registered: 18-8-2005
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Quote: Originally posted by DougTheMapper  |
NaHCO3(aq) + HCl(aq) --> NaCl(aq) + CO2(g) + H2O(l)
Imagine the reaction was conducted inside a sealed, fixed-volume system. How would one go about calculating the pressure at which the gas pressure of
the CO2 would be at equilibrium with the re-formation of NaHCO3 (Or Na2CO3)?
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???
This is not a reversible reaction so NaHCO3 Or Na2CO3 will not re-form.
Given the volume of the sealed container and after the steady state is achieved i.e. all reactants are consumed and heat generated by reaction is
fully dissipated to get the sealed tube back to original temperature, you can calculate the pressure by using gas law.
This will be an approximate answer as it will not account for vapour pressure of water and solubility of CO2 in water. For more accurate answer these
effects can be factored into the calculation.
gsd
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