C6 - Equilibria Flashcards
How is a reversible reaction represented?
2 half arrows pointing in opposite directions
What is needed for a dynamic equilibrium to occur?
Needs to be carried out in a closed container so that the reactants and products cannot escape
Why is the equilibrium dynamic?
Because both the forward and reverse reactions are ongoing
What is the difference in rates when in equilibrium?
Rates for forward and reverse reactions are the same
In equilibrium do the concentrations have to be equal?
No the proportions may be different, however the net concentration is equal as the reactions are occurring at the same rate
What is Le Chatelier’s principle?
If a factor affecting the position of an equilibrium is altered, the position of the equilibrium shifts to oppose the effect of the change
If the temperature is increased, what reaction is favoured?
The endothermic reaction
If the temperature is decreased, what reaction is favoured?
The exothermic reaction
If the pressure is increased, which reaction is favoured?
The reaction forming the fewer moles
(only in gases, pressure doesn’t effect the other states)
If the pressure is decreased, which reaction is favoured?
The reaction forming more moles
(only in gases, pressure doesn’t effect the other states)
If there is an increase in concentration of reactants, which reaction is favoured?
The forward reaction
If there is an increase in concentration of products, which reaction is favoured?
The reverse reaction
If there is an addition of a catalyst how is the equilibrium changed?
No change in position, but equilibrium is reached quicker
What does a shift left in equilibrium mean?
The reverse reaction is favoured
What does a shift right in equilibrium mean?
The forward reaction is favoured
What is the equation of the equilibrium constant (Kc) given the general reaction aA + bB = cC + dD
Kc =[C]c[D]d / [B]b[A]a
(lowercase is to the power of, so C to the power of c)
What does a Kc of > 1 mean?
The concentration of products is greater than the concentration of reactants and we say that the equilibrium lies to the right hand side
What does a Kc of < 1 mean?
Then the concentration of reactants is greater than the concentration of products and we say that the equilibrium lies to the left hand side
In Kc calculations which part is the ratios used in?
Reacting moles
What is the only factor that effects Kc?
Temperature
