Editing Partial pressure (section)

==Equilibrium constants of reactions involving gas mixtures==
It is possible to work out the [[equilibrium constant]] for a chemical reaction involving a mixture of gases given the partial pressure of each gas and the overall reaction formula. For a reversible reaction involving gas reactants and gas products, such as:
<chem display="block">{\mathit{a}A} + {\mathit{b}B} <=> {\mathit{c}C} + {\mathit{d}D}</chem>

the equilibrium constant of the reaction would be:
<math display="block">K_\mathrm{p} = \frac{p_C^c\, p_D^d} {p_A^a\, p_B^b}</math>

{| border="0" cellpadding="2"
|-
|align=right|where:
|&nbsp;
|-
!align=right|<math>K_p</math>
|align=left|= &nbsp;the equilibrium constant of the reaction
|-
!align=right|<math>a</math>  
|align=left|= &nbsp;coefficient of reactant <math>A</math>
|-
!align=right|<math>b</math>
|align=left|= &nbsp;coefficient of reactant <math>B</math>
|-
!align=right|<math>c</math>  
|align=left|= &nbsp;coefficient of product <math>C</math>
|-
!align=right|<math>d</math>
|align=left|= &nbsp;coefficient of product <math>D</math>
|-
!align=right|<math>p_C^c</math>
|align=left|= &nbsp;the partial pressure of <math>C</math> raised to the power of <math>c</math>
|-
!align=right|<math>p_D^d</math>
|align=left|= &nbsp;the partial pressure of <math>D</math> raised to the power of <math>d</math>
|-
!align=right|<math>p_A^a</math>
|align=left|= &nbsp;the partial pressure of <math>A</math> raised to the power of <math>a</math>
|-
!align=right|<math>p_B^b</math>
|align=left|= &nbsp;the partial pressure of <math>B</math> raised to the power of <math>b</math>
|}

For reversible reactions, changes in the total pressure, temperature or reactant concentrations will shift the [[Chemical equilibrium|equilibrium]] so as to favor either the right or left side of the reaction in accordance with [[Le Chatelier's Principle]]. However, the [[Chemical kinetics|reaction kinetics]] may either oppose or enhance the equilibrium shift. In some cases, the reaction kinetics may be the overriding factor to consider.