Equilibrium, acid base and pH Flashcards
Whats a homogeneous Equilibria?
When all species in the equilibrium equation have the same states
Whats a heterogeneous Equilibria?
When species in the equation have different states
What states are included in Kc?
gas (g) and aqueous (aq)
What states are included for Kp
Gases (g) only
Give the expression for Kc
Kc = [C]^c [D]^d / [A]^a [B]^b
How do you calculate concentration at equilibrium?
Equilibrium moles / Total volume (dm3)
What is Kc?
Equilibrium constant for concentration
What is Kp?
The equilibrium constant in terms of partial pressure
What is mole fraction?
Proportion of volume of gas with total volume of gas in a gas mixture.
What is partial pressure
The contribution the gas makes to the total pressure
How do you calculate mole fraction?
Equilibrium moles / total moles
How do you calculate partial pressure?
mole fraction x total pressure
The sum of the partial pressures = ?
The total pressure
KPa x KPa =
KPa^2
What information does the value of K give you?
the position of the equilibrium
where is the equilibrium when K = 1?
Halfway
where is the equilibrium when K > 1?
To the right
where is the equilibrium when K < 1?
To the left
When will K change?
ONLY CHANGE IN TEMPERATURE
If concentration of products increase where does equilibrium shift and why?
To the reactants (left). Because it opposes change in order to keep K the same.
If pressure increases where does equilibrium shift and why?
To the side with least moles because K stays the same.
How does a catalyst change K?
It doesn’t
What’s a Bronsted-Lowry Acid
A proton donor
What’s a Bronsted-Lowry Base
A proton acceptor
What’s a conjugate acid-base pair
Two species that can be inter converted by the transfer of a proton
What’s H3O+
Hydronium
What’s a monobasic acid?
When 1 mol of protons are donated per mol of acid.
What’s a diprotic acid?
When 2 mols of protons are donated per mol of acid
What’s triprotic acid?
When 3 mols of protons are donated per mol of acid
How do you calculate a diluted concentration?
origional conc of whats wanted x volume of whats wanted/ total volume of solution
How do you calculate pH?
-log [H+]
How do you calculate [H+] from pH?
10^-pH
will a low concentration of [H+] have a high or low pH
High pH
How should you round pH?
To 2dp
How many more H+ is there in pH1 than in pH2?
x10
Whats Ka?
Acid dissociation constant
The expression for Ka?
Ka= [H+][A-] / [HA]
Will a strong acid have a small or big pKa?
Small pKa
What is pKa?
A negative logarithm used to compare weak acids more easily
What assumption can you make for using strong acids?
[H+] = [Acid]
What two assumptions can you make for weak acids?
1) [H+] = [A-]
2) [HA] equib = [HA] start
What is Ka for weak acids?
Ka = [H+]^2 / [HA]
Why don’t the assumptions for weak acids always work?
1) When there is dissociation of H2O [H+] does not = [A-]
2) In strong acids there is a lot of dissociation so [HA] equib does not = [HA]start
What is Kw?
Ionic Product of water
What is the expression for Kw?
Kw= [H+][OH-]
What is Kw at room temperature?
1 x 10^-14
What assumption can you make for Strong bases?
That [OH-] = [HA]
