Equilibrium constant - K value

[marciobarbalho]

Dear friends...

 

Could you shed some light on this?

 

If we have

 

[math]K = \frac{y}{x}[/math]

 

would it be correct to say that such an equation could be applied to calculations involving either ideal gas or real gas?

 

Can we have (????)

 

[math] K_{i} = \frac{y_{i}}{x_{i}} = \frac{\phi^{vap}_{i}}{\phi^{liq}_{i}} [/math]

 

[math]\phi[/math] = fugacity coefficient

 

are they always interchangeable?

 

Thank you.

 

Marcio