UNIT 7 Flashcards
What are electrolytes?
Solute which form ions when dissolved
What is the difference betwee strong electrolytes and weak electrolytes?
Strong- ionize completely
Weak- ionize partially
What is an acid?
proton donor
What is a conjugate base?
potential proton acceptor, acid that gave up proton
What is a base?
A proton acceptor
What is a conjugate acid?
base that accepted protn, potential proton donor
What is a Amphiprotic species?
Acidic and basic properties
what do amino acids do when they are dissolved?
When dissolved, they produce a zwitterion
What is a Zwitterion?
Species that has both positive and negative charge
What is autoprotolysis?
Spontaneous reaction of moelcuels to give a pair of ions
Strong acid/base does what in solution?
There is no undissociated solute molecules left in solution
Weak acid/base does what in solution?
Incomplete, give solution with significant quantities of both parent and conjugate
What is the mass-action effect?
Shift in position of the equilibrium caused by adding one of the reactant or products to a system
Do equillibrium constants give the rate of reaction?
No
What do equilibrium constnat expressions give?
describe relationships among reactant and products at eq
β> reaction direction
Reaction completeness
Calculation of error
What is the equilibrium constant expression?
πΎ=[π]^π¦[π]^π§/[π]^π€[π]^π₯
When conyou assume ππ»π΄βπ»3π+βππ»π΄?
When acids have small dissociation constants and high molar concentration
What are the steps to determine equilibrium problems?
- balanced equations
- State what is being found
- Write eq constants
- Write mass balances
- write charge balance
- Count # eqs and unknowns
- Make approximations
- Solve euqations
- Check validity
What is included in balance equations?
The mass is equal to the mass of all the species that are not water or the sovlent
What is the basis of charge balance equation?
M of positive = M negative charge
When are assumptions?
Only in mass-balance and charge balance to redue the number of unknowns to be equal or less than the equations
β? no assumptions for the equillibrium constnat
What happens when there is assumption
If there is dingificant error, you have t recalculate without assumptions
What do buffer solution resist?
Resist changes inpH when it is diluted or when acids/bases are added
Maintain pH relatively constant
What does the pH of the buffer depend on?
The position of the equilibria
Ratio between the concentrations of the acid and conj
What is the Henderson-Hasselbach equation?
ππ»=ππΎπ+πππ(ππππ΄/ππ»π΄)
When would the solubility of a precipitate increase?
In the presence of reagent that form complexes with the anion/cation in the precipitate
What could increase the precipitate solubility?
Excess reagent
What can be done with solubility differences?
Precipitating agents permit seperation based on it.
What is the electrolyte effect (salt effect)
Results from teh electrostatic attractive and repulsive forces between the ions of an electrolyte and the ion in an equilibrium
Kβ
What is the magnitude of the electrolyte effect highly dependent on?
Charges of the participates
neutral species are not affected
ionic participants, magnitude the electrolyte effect increases with charge
What is the ionic strength calculator?
π= 1/2 ([π΄]π^2+[π΅]π^2+[πΆ]π^2+β―)
What are activity coefficients?
Measure of the effectiveness with which a species influences an eq
- independent of the nature of the electrolyte and dependent only on the ionic strength
Decreases when the charge of the species increases
What is the activity coefficient equation?
πΎπ π=πΎβ²π π.πΎπ₯ππΎπ¦π
