PH,acid,base,buffers

Question 1

Is water an electrolyte

Answer 1

No

Question 2

Does water conduct electricity and explain why

Answer 2

Yes, because it ionizes in small extent. Thats called water self-ionization

Question 3

What is self-ionozation konstant

Answer 3

Kw=10^(-14) mol²/dm⁶
Kw=[H+][OH-]

Question 4

Explain how conc.of H+ and OH- impact acidity of the solutiom

Answer 4

[H+]=[OH-]=>neutral
[H+]>[OH-]=>acidic
[H+]<[OH-]=>basic

Question 5

What is formula for pH and [H+]

Answer 5

pH=-log[H+]
[H+]=10^(-pH)

Question 6

How does pH impact acidity of the solution

Answer 6

pH=7=>neutral
pH>7=>basic
pH<7=>acidic

Question 7

What are Arrhenius definition of acid and bases

Answer 7

Acid=substance that gives H+ when ionized in water
Base=substance that gives OH- when ionized in water

Question 8

What are acid and bases in Brønsted-Lowry theory

Answer 8

Acid donates proton(H+)
Bases accepts proton(H+)

Question 9

What are conjugate acid/bases

Answer 9

Products of bases/acids when they react w water

Question 10

What is Lewis theory when it comes to acid and bases

Answer 10

It bases on accepting and donating e-.Acid is the one that accepts and base is the one that donates a pair on non binding e-

Question 11

What are strong acids and give example

Answer 11

They have high tendency to donate protons. In aquous solution they prpduce H3O+ amd they go to completion(aka,they are fully ionized)
Ex:
HCL
HBr
HI
H2SO4
HNO3
HClO4

Question 12

What are strong bases and give and example

Answer 12

They have high tendenca to accept protons and with water form OH-. They are fully ionized
Ex:
NaOH
LiOH
KOH
Ca(OH)2
Sr(OH)2
Ba(OH)2

Question 13

What are weak acids

Answer 13

Reaction with water is incomplete
Ex:
CH3COOH
HCN
H2CO3
H2SO3
H2S
HF

Question 14

Write formula for pKa

Answer 14

pKa=-log(Ka)

Question 15

What is degree of ionization of weak acid

Answer 15

Number of ionized molecules×100/num.dissolved in water
[H+]/[HA]0

Question 16

What are weak bases and examples

Answer 16

Reaction w water is incomplete
NH3
NH2CH3
C5H5N-pyridine

Question 17

Formula for pKb

Answer 17

pKb=-log(Kb)

Question 18

How are salts formed

Answer 18

With neutralization reaction(reactuon between acid and bases)

Question 19

Do conjugated bases/acid of strong acid/bases have acidic/basic propertie

Answer 19

No, it only applies if they are from the weak base/acid

Question 20

What is hydrolysis reaction

Answer 20

Reation between ion and water

Question 21

Relationship between Ka and Kb

Answer 21

Ka×Kb=Kw
pKa+pKb=pKw

Question 22

What is a buffer solution

Answer 22

It resists changes of pH. It stays constant even when small amouns of acids and alkalis are added. pH doesnt change whem solution is dilluted

Question 23

What does buffer solution contain

Answer 23

Weak acid and its conjugate basd(HCN/CN-)
Weak base and its conjugate acid(NH3/NH4+)
And they are at equilibrium

Question 24

What is eq.constant for the reaction of conjugate bases/acids w water

Answer 24

K=1/Ka or Kb

Question 25

What does amount of strong acid/base have to do w the buffer solutions

Answer 25

For them to work, the amount has to be smaller than the one of conjugate acid/base

Question 26

What is buffer capacity

Answer 26

Mole sof acid or base needed to chenge pH of buffer solution by 1

Question 27

How to depermine pH of a buffer solution

Answer 27

[H+]=Ka×[HA]/[A-] Those are conc.at equilibrium and we can assume they are the same as when we prepared the solution •If [HA]=[A-] [H+]=Ka •if [HA] isnt equal [A-] we have to use **Handerson-Hasselback equation** pH=pKa+log([base]/[acid])

Question 28

What is pH of human blood

Answer 28

7.4

Question 29

What are buffer systems in human body

Answer 29

•carbonic acid/bicarbonate -H2CO3 •haemoglobin •phosphate

Question 30

What is alkalosis and what is acidosis

Answer 30

Alkalosis-blood pH is higher than 7.45 Acidosis-blood pH is lower than 7.35

Question 31

Give example on alkalosis and acidosis

Answer 31

Alkalosis-hyperventikation due to panic attack Acidosis-excessive accumulation of CO2 in blood after an anaerobic effort

Question 32

What is acid-base indicator

Answer 32

Weak acid or base that has different colors in its natural/uncharged and ionic forms

Question 33

In what amounts is H3O+ added

Answer 33

Small amounts

Question 34

Name some indicators

Answer 34

Methyl orange, bromethil blue, phenolphthalein

Question 35

Over how many pH units do colors change with indicators

Answer 35

Over 2pH units

Question 36

What is acid-base titration

Answer 36

We determine amounts of acid/base present present by measuring the V of standard alkaline/acid needed to neutrakize it

Question 37

What is end-point of titration

Answer 37

When indicator changes color

Question 38

What is titration curve

Answer 38

Graphical representation of the pH of a solution during a titration

Question 39

What is equivalence point for strong acid and strong base

Answer 39

7

Question 40

What is equivalence point

Answer 40

Point in titration where amount of added reagent has reacted exactly with the solution in the flask

Question 41

Whats unusual with titration of weak acid and strong base

Answer 41

We have a point where both acid and its conjugate base are present(half-way poimt pH=pKa), equivalence point is >7