Calculate the value of the equilibrium constant

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SUMMARY

The equilibrium constant (K) for the reaction 2NaHCO3(s) <--> Na2CO3(s) + H2O(g) + CO2(g) at 110.0 degrees C can be calculated using the total pressure of the gases at equilibrium, which is 1.648 atm. Since solid sodium bicarbonate has negligible vapor pressure, it is treated as a constant and does not appear in the equilibrium expression. The equilibrium constant will only include the partial pressures of the gaseous products, H2O and CO2, derived from the total pressure.

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  • Understanding of chemical equilibrium concepts
  • Knowledge of equilibrium constant expressions
  • Familiarity with gas laws and partial pressures
  • Basic thermodynamics related to phase changes
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  • Calculate the partial pressures of H2O and CO2 from the total pressure of 1.648 atm
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Homework Statement


The total pressure of gases in equilibrium with solid sodium hydrogen carbonate at 110.0 degrees C is 1.648 atm, corresponding to the reaction

2NaHCO3(s) <--> Na2CO3(s) + H2O(g) + CO2(g)

a) Calculate the value of the equilibrium constant at 110.0 degrees C.



The Attempt at a Solution


I don't know how to begin this because I don't know how to find the initial partial pressure of sodium hydrogen carbonate. How am I supposed to use P total at equilibrium in this problem?
 
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The solid sodium bicarbonate has negligible vapor pressure at 110 degrees C. We usually treat solids as constants, which we then divide out of the equilibrium constant; the only terms you should be left with in your expression for K are from gaseous water and gaseous carbon dioxide.

This approach for dealing with solids holds true in general, unless the equilibrium being studied occurs in a solid solution (e.g., molten rock.)
 

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