Equilibria Flashcards
how can equilibrium be reached?
in a closed system
- reacted and products can’t escape
How do you know when equilibrium has been reached?
when the properties of the system (e.g. colour density) don’t change with time
What are the features of dynamic equilibrium?
Forward rate = backward rate
Concentration remains constant
What is Le Chatelier’s principle?
Equilibrium will shift to oppose the change
What three factors affect a position of equilibrium?
concentration
Pressure
Temperature
How does concentration affect the position of equilibrium?
add a chemical (inc concentration) equilibrium moves to get rid of it
remove a chemical (decrease concentration) equilibrium move to make more of it
How does pressure affect the position of equilibrium?
only affects chemical equilibrium that involves gases
raise pressure - equilibrium moves lower it
Lower pressure - equilibrium moves to raise it
How is the temperature affect the position of equilibrium?
Increase temp - equilibrium moves to cool it
decreased temp - equilibrium moves to heat it
what is an exothermic reaction?
Gives out heat to the surroundings
What is an endothermic reaction?
Takes and heat from surroundings
What happens to equilibrium if temperature is increased?
shifts to oppose this equilibrium
shifts to endothermic direction to try reduce temperature by absorbing added heat
what happens to equilibrium if temperature is decreased.
equilibrium shifts in exothermic Direction to try increase the temperature by giving out the added heat
what effect does a catalyst have on the yield and position of equilibrium?
none
what effect does equilibrium have on yeild?
equilibrium shift to right = yield increases
Shifts two left = yield decreases
What is the haber process formula?
N2 + 3H2 ⇌ 2NH3
what is the Haber process?
The synthesis of ammonia from nitrogen and hydrogen
what is the optimum temperature in the Haber process?
The Haber processes exothermic
the best equilibrium yield of ammonia is obtained at low temperatures
so equilibrium moved to the right
rate of reaction is slow
what is the optimum pressure in the Haber process?
the Haber process is favoured at high-pressure
increasing the pressure moves equilibrium to the side with fewer moles of gas
Higher pressure produces greater equilibrium of ammonia
What is a compromised condition?
Give a balance between yield rate and cost
what is homogeneous equilibrium?
A system where reactant and products are in the same phase
What is the equation for Kc
Kc = [C] [D] (products)
————
[A] [B] (reactants)
Where is equilibrium if Kc value is less than 1
equilibrium lies towards the reactants
Where is equilibrium if Kc value is greater than 1
towards the products
