(L3) Module 1 L3 - Equilbrium Flashcards
What is equilibrium?
There’s an equal amount of forwards and backwards reactions.
(products–>reactants to reactants–>products)
Meaning the relative amounts of products and reactants stay the same. This may not mean equal amounts but it means that they stay at that specified mass. Mass ratio could be anything.
At equilibrum, does a reaction stop?
NO! It’s constantly going back and forward from
products–>reactants to reactants–>products
It reaches an equal amount of forwards and backwards reactions.
What is a reaction Quotient?
Reaction Quotient, Q.
We measure concentrations of Reactants:Products
- It helps to determine if a reaction has gone to completion or not
- It helps to measure if a reaction has enter equilibrium
What is equilibrium constant? What does it equal.
Equilibrium constant, K.
At equilbirum, reaction quotient, Q = equilbirum constant K.
Q=K at equilibrium.
Q will decrease/increase till it equals K.
What is Kc equation?
Products over reactants.
Coefficents become, to the power of.
Only gas/Aqueous.
No solids/Liquids - as their concentration is constant.
Generally given at 25C. Kc has no units.
How are reactants/products treated when Q is less than K?
Q needs to become bigger, so reactants are converted into products.
Q=products over reactants. 10/5=2 compared to 20/1=20
How are reactants/products treated when Q is more than K?
Q needs to become smaller, so products are converted into reactants.
Q=products over reactants. 20/1=20 compared to 10/5=2
Does equilbrium composiiton change? Depending on wether we start with pure product or pure reactant?
Nope! Equilbirum constant remains the same, as Kc only has 1 output for what’s inputted.
K depends on pressure or temperature.
What can Kc over 1 tell us.
If Kc is far to the right, over 1, then products are favoured more.
What can Kc under 1 tell us.
It tell us that rectants are favoured more.
What can Kc at 1 tell us.
Equilbrium has been reached.
What does ICE table stand for?
Initial, change, equilibrium. All calculated in concentration (mol l^-1) as ICE table AKA concentration table.
Le Châtelier’s principle
“If a system at equilibrium is disturbed, it will move in such a way to counteract the disturbance and restore equilibrium.”
What other components can we utilise with respect to Le Châtelier’s principle?
Compare Le Châtelier’s principle to our Q and K.
What can we use Le Châtelier’s principle to determine?
How a system will respond to changes in:
-Pressure
-Concentration (amount of products/reactants.)
-Temperature
