(L4) Module 1 L4 - Equilibria and Solubility Flashcards
What is La Chatelier’s principle?
if a system at equilibrium is disturbed, it will move in such a way to counteract the disturbance and restore equilibrium
Frequency of La Chaterlier’s principle working
90%
What happens if we add reactant?
Then Q<K… reactant reduces and product increases until Q=K. Equilibrium moves to the right.
What happens if we removed reactant?
Then Q<K… reactant increases and product reduces until Q=K. Equilibrium moves to the left.
Inert meaning
Chemically unreactive
How can we change pressure?
Changing volume or adding inert gas
What happens if we increases pressure?
Qc=1/V.
If we increase pressure we decrease Qc.
Qc<K, meaning eqbm will move to the right.
What happens if we decrease pressure?
Q=1/V.
If we decrease pressure we increase Qc.
Qc>K. Eqbm will move to the left.
Does changing volume effect an equation with balanced gas mols?
No, if an equation has balanced gas mols then changing the volume doesn’t effect the Qc, as it’s cancelled out.
Does adding inert gas to a balanced gas equation effect Qc?
Nope! There’s no term for inert gas in the expression of Qc=1/V. It’s not involved in the reaction.
What is a saturated solution?
Formed when a maximum amount of solute is dissolved in a particular volume of solvent at temperature, T.
What equilibrium exists in a saturated solution?
solute(s) ⇌ solute(aq)
What does solubility depend on?
- Chemical nature of solute and solvent
- Temperature
- pressure, p (for gaseous solutes)
What is K,sp?
Solubility Product.
Equilibrium constant for dissolution of a slightly soluble salt in water.
What appears in equilibrium equations?
gases and aqueous solutions
not solids / liquids as their concentration is constant
How to work out K,sp given solubility?
conc = s/v
so if v=1: conc=s.
put this into K,sp =[Ag][Cl]
amd boom, K,sp, which has no units.
1:1 electolyte Ksp and s equation
What does incredibly low Ksp mean for soubility (like 10^-10)
very low solubility
Calculating s given Ksp.
Square that shit
What is ionic product?
Qsp
What can Ksp and Qsp tell us?
Wether or not a precipitate will form when mixing aqueous solutions and ions.
If Qsp < Ksp
no precipitate will form
If Qsp > Ksp
precipitation will occur
How to calculate Qsp?
Conc’s into usual Q equations
What is the common ion effect?
Presence of a common ion wil always decrease the solubility of an ionic solid.
larger K means what?
more soluble as more product favoured
