equilibrium and acid base 2 (needs to be expanded in the future)

Question 1

net ionic equation meaning

Answer 1

The net ionic equation is the chemical equation that shows only those elements, compounds, and ions that are directly involved in the chemical reaction.

Question 2

what is the value for Kw?

Answer 2

1.0 x 10⁻¹⁴ mol/L (can find on data booklet)

Question 3

properties of acids

Answer 3

tastes sour
pH < 7
pOH > 7
turns blue litmus red
corrosive
neutralizes bases, conductive
act molecular before they are dissolved; thus they ionize

Question 4

properties of bases

Answer 4

tastes bitter
pH > 7
pOH < 7
turns red litmus blue
feels slippery
corrosive
conductive
act ionic, and thus they dissociate when dissolved

Question 5

arrhenius definition of acid and base

Answer 5

acid: presence of H+ or H3O+ ions
base: presence of OH- ions

Question 6

what is the sig digs rule for pH/pOH?

Answer 6

the number of digits following the decimal place in the pH value is equal to the number of sig digs in the [H3O+(aq)]

Question 7

what is the Bronstead-Lowry Definition of an acid and base?

Answer 7

an acid is a chemical species(anion, cation, or molecule) that loses a proton
A base is a chemical species that gains a proton
Like in electrochemistry where e- are transferred… now we transfer H+

Question 8

amphiprotic/amphoteric meaning

Answer 8

a substance that acts as a bronstead-lowry acid in some reactions and a bronstead-lowry base in other reactions. (can both donate and accept a proton)

Question 9

The ________ an acid, the weaker its conjugate base

Answer 9

stronger

Question 10

The ______ an acid, the stronger its conjugate base

Answer 10

weaker

Question 11

an acid capable of donating only one proton is called __________

Answer 11

monoprotic
eg) HCl(aq), HNO₃(aq), HOCl(aq) etc.

Question 12

if an acid can transfer more than one proton, it is called __________

Answer 12

polyprotic (diprotic if 2 protons, triprotic if 3 protons)

Question 13

a base capable of accepting only one proton is called a _________________ or _________

Answer 13

monoprotic base
monobasic

Question 14

a base that can accept more than one proton is called a _________________ or _________

Answer 14

polyprotic base
polybasic

Question 15

strong acids ionize ______________ (forward reaction/products formed) in water to form H₃O+(aq)

Answer 15

quantitatively
(percent reaction = 100%)

Question 16

formula for % ionization/percent reaction?

Answer 16

(yield/max) x 100%
OR
[H3O+(aq)]/[WA] x 100% ( weak acids)

Question 17

how do you calculate kb?

Answer 17

kw/ka

Question 18

Buffer capacity

Answer 18

the limit of the ability of a buffer to maintain a pH level

Question 19

A nonspontaneous reaction

Answer 19

a reaction that does not favor the formation of products at the given set of conditions

Question 20

For a week acid/base titration curve where is the equivalence point?

Answer 20

for a weak acid being titrated with SB, pH is above 7.

For a weak base being titrated with a SA, pH is below 7

Think the strong acid/base influences the pH more.

Question 21

how should you choose an appropriate indicator for titration?

Answer 21

choose an indicator where the middle of it matches the equivalence point/end point

Question 22

What is Kw?

Answer 22

The equilibrium constant for water

Question 23

acids are listed in order of __________ strength on the left side and bases are listed in order of __________ strength on the right side

Answer 23

decreasing
increasing

Question 24

what is the formula for kₐ for strong acids and weak acids?

Answer 24

strong acid: kₐ = [H₃O⁺(aq)][A-(aq)]/[HA]
weak acid: kₐ = [H₃O⁺(aq)]^2/[HA]

Question 25

What is the formula for Kw?

Answer 25

Kw = ka x kb

Question 26

What are buffers?

Answer 26

Buffers are chemicals that, when added to water, protect the solution from large pH changes when acids or bases are added to them.

Question 27

what is the difference between the endpoint and the equivalence point?

Answer 27

Although they are similar, the endpoint is the qualitative change in colour by an indicator to show the reaction to completion.

The equivalence point is the quantitative change, where the volume of titrant required for the reaction to go to completion.

Endpoint: colour change.
equivalence point: volume required to go to completion.

Question 28

what is the buffer region?

Answer 28

The buffer region is the flat area of a curve,

Question 29

what is an analyte?

Answer 29

the part that is being titrated.

Question 30

Draw the graphs for:
- a strong acid titrated with a strong base
- a strong base titrated with a strong acid

Answer 30

• pH of 7 at the equivalence point because water and a neutral salt are made

Question 31

Draw the graphs for:
- A weak acid titrated with a strong base
- a weak base titrated with a strong acid

Answer 31

• if weak acid, then pH of > 7 at the equivalence point
• if weak base, then pH of < 7 at equivalence point
• bottom “flat region is not as flat as with a strong acid/strong base

Question 32

Draw the graphs for:
- a weak polyprotic acid titrated with a strong base
- a weak polyprotic base titrated with a strong acid

Answer 32

• more than one equivalence point