UNIT 7

Question 1

What are electrolytes?

Answer 1

Solute which form ions when dissolved

Question 2

What is the difference betwee strong electrolytes and weak electrolytes?

Answer 2

Strong- ionize completely

Weak- ionize partially

Question 3

What is an acid?

Answer 3

proton donor

Question 4

What is a conjugate base?

Answer 4

potential proton acceptor, acid that gave up proton

Question 5

What is a base?

Answer 5

A proton acceptor

Question 6

What is a conjugate acid?

Answer 6

base that accepted protn, potential proton donor

Question 7

What is a Amphiprotic species?

Answer 7

Acidic and basic properties

Question 8

what do amino acids do when they are dissolved?

Answer 8

When dissolved, they produce a zwitterion

Question 9

What is a Zwitterion?

Answer 9

Species that has both positive and negative charge

Question 10

What is autoprotolysis?

Answer 10

Spontaneous reaction of moelcuels to give a pair of ions

Question 11

Strong acid/base does what in solution?

Answer 11

There is no undissociated solute molecules left in solution

Question 12

Weak acid/base does what in solution?

Answer 12

Incomplete, give solution with significant quantities of both parent and conjugate

Question 13

What is the mass-action effect?

Answer 13

Shift in position of the equilibrium caused by adding one of the reactant or products to a system

Question 14

Do equillibrium constants give the rate of reaction?

Answer 14

No

Question 15

What do equilibrium constnat expressions give?

Answer 15

describe relationships among reactant and products at eq
–> reaction direction
Reaction completeness
Calculation of error

Question 16

What is the equilibrium constant expression?

Answer 16

𝐾=[𝑌]^𝑦[𝑍]^𝑧/[𝑊]^𝑤[𝑋]^𝑥

Question 17

When conyou assume 𝑐𝐻𝐴−𝐻3𝑂+≈𝑐𝐻𝐴?

Answer 17

When acids have small dissociation constants and high molar concentration

Question 18

What are the steps to determine equilibrium problems?

Answer 18

1. balanced equations
2. State what is being found
3. Write eq constants
4. Write mass balances
5. write charge balance
6. Count # eqs and unknowns
7. Make approximations
8. Solve euqations
9. Check validity

Question 19

What is included in balance equations?

Answer 19

The mass is equal to the mass of all the species that are not water or the sovlent

Question 20

What is the basis of charge balance equation?

Answer 20

M of positive = M negative charge

Question 21

When are assumptions?

Answer 21

Only in mass-balance and charge balance to redue the number of unknowns to be equal or less than the equations
–? no assumptions for the equillibrium constnat

Question 22

What happens when there is assumption

Answer 22

If there is dingificant error, you have t recalculate without assumptions

Question 23

What do buffer solution resist?

Answer 23

Resist changes inpH when it is diluted or when acids/bases are added
Maintain pH relatively constant

Question 24

What does the pH of the buffer depend on?

Answer 24

The position of the equilibria

Ratio between the concentrations of the acid and conj

Question 25

What is the Henderson-Hasselbach equation?

Answer 25

𝑝𝐻=𝑝𝐾𝑎+𝑙𝑜𝑔(𝑐𝑁𝑎𝐴/𝑐𝐻𝐴)

Question 26

When would the solubility of a precipitate increase?

Answer 26

In the presence of reagent that form complexes with the anion/cation in the precipitate

Question 27

What could increase the precipitate solubility?

Answer 27

Excess reagent

Question 28

What can be done with solubility differences?

Answer 28

Precipitating agents permit seperation based on it.

Question 29

What is the electrolyte effect (salt effect)

Answer 29

Results from teh electrostatic attractive and repulsive forces between the ions of an electrolyte and the ion in an equilibrium
K’

Question 30

What is the magnitude of the electrolyte effect highly dependent on?

Answer 30

Charges of the participates
neutral species are not affected
ionic participants, magnitude the electrolyte effect increases with charge

Question 31

What is the ionic strength calculator?

Answer 31

𝜇= 1/2 ([𝐴]𝑍^2+[𝐵]𝑍^2+[𝐶]𝑍^2+⋯)

Question 32

What are activity coefficients?

Answer 32

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

Question 33

What is the activity coefficient equation?

Answer 33

𝐾𝑠𝑝=𝐾′𝑠𝑝.𝛾𝑥𝑚𝛾𝑦𝑛