Equilibrium Flashcards
What is dynamic equilibrium?
> Rate of forward reaction = rate of backwards reaction
> Concentration remains constant
What is Le Chatlier’s principle?
> If any factor of an equilibrium is changed (temperature/pressure/concentration), the equilibrium position will shift/move to counteract that change
What is the effect of increasing temperature?
As increasing temperature is an exothermic process, equilibrium will shift to endothermic side
What is the effect of increasing pressure?
As side with higher moles will have more pressure, equilibrium will shift to the side with fewer moles
What is the effect of increasing concentration?
Increasing concentration means products will have higher concentrations, so equilibrium will shift to reactants
[HABER PROCESS]
Why 450°C?
N₂ + 3H₂ ⇌ 2NH₃
> Rate of reaction is exothermic
So higher temperatures = lower yield
But higher temperature = faster rate of reaction (compromise)
[HABER PROCESS]
Why 20 MPa (200 bar)?
N₂ + 3H₂ ⇌ 2NH₃
> More moles on reactants
So higher pressure = higher yield
But equipment to hold higher pressures is expensive (so compromise)
What is a homogeneous system?
A system where chemical compositions (atoms or molecules) and physical properties are equal
What is a heterogeneous system?
A system where chemical compositions (atoms or molecules) and physical properties are different
Define Kc:
> Equilibrium constant
Ratio of concentrations of products to reactants raised to the power of their stoichiometric coefficients (big mole number)
