Chemical Systems and Equilibrium Flashcards
1
Q
Chemical Equilibrium
A
- a state in which the forward and backward reactions are occuring at the same rate, so there is no net change in [ ]
2
Q
Dynamic Equilibrium
A
- after equilibrium, macroscopic properties remain constant
- change is occuring at molecular level
3
Q
Factors of Equilibrium
A
- only in closed system
- can be established in either direction
- constant macroscopic properties
4
Q
Two Types of Equilibrium
A
homogeneous equilibrium: same state
heterogeneous: different states
5
Q
Equilibrium Constant Expression
A
aA + bB -> cC + dD
Keq = [C]c [D]d / [A]a [B]b
products over reactants
6
Q
Approximation with Small Keq
A
[initial] / Keq
if > 500, approximation is valid
7
Q
Reaction Quotient (Q) and Keq
A
products over reactants
- Q < Keq, shift right
- Q > Keq, shift left
8
Q
Solubility Equilibrium
A
- equilibrium that occurs between a solute and a solvent in a closed system
9
Q
Ksp
A
Ksp = [ion 1][ion 2]
concentration of solids don’t change
10
Q
Q and Ksp
A
- Q > Ksp: precipitate will form
- Q < Ksp: no precipitate
11
Q
Arrhenius Theory
A
- bases are ionic hydroxides that dissociate into metal cations and hydroxide ions
- acids ionize in water to produce hydrogen ions (protons)
12
Q
Limitations of Arrhenius Theory
A
- cannot always predict whether a substance is an acid or base
- acid base reactions do not always involve water
- no evidence to show H+ ion exists
13
Q
Bronsted-Lowry Concept
A
- acid is proton donor
- base is proton acceptor
- conjugate acid-base pair are two substances that differ by only one proton
14
Q
A
