PH,acid,base,buffers Flashcards

1
Q

Is water an electrolyte

A

No

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2
Q

Does water conduct electricity and explain why

A

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

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3
Q

What is self-ionozation konstant

A

Kw=10^(-14) mol²/dm⁶
Kw=[H+][OH-]

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4
Q

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

A

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

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5
Q

What is formula for pH and [H+]

A

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

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6
Q

How does pH impact acidity of the solution

A

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

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7
Q

What are Arrhenius definition of acid and bases

A

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

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8
Q

What are acid and bases in Brønsted-Lowry theory

A

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

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9
Q

What are conjugate acid/bases

A

Products of bases/acids when they react w water

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10
Q

What is Lewis theory when it comes to acid and bases

A

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-

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11
Q

What are strong acids and give example

A

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

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12
Q

What are strong bases and give and example

A

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

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13
Q

What are weak acids

A

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

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14
Q

Write formula for pKa

A

pKa=-log(Ka)

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15
Q

What is degree of ionization of weak acid

A

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

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16
Q

What are weak bases and examples

A

Reaction w water is incomplete
NH3
NH2CH3
C5H5N-pyridine

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17
Q

Formula for pKb

A

pKb=-log(Kb)

18
Q

How are salts formed

A

With neutralization reaction(reactuon between acid and bases)

19
Q

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

A

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

20
Q

What is hydrolysis reaction

A

Reation between ion and water

21
Q

Relationship between Ka and Kb

A

Ka×Kb=Kw
pKa+pKb=pKw

22
Q

What is a buffer solution

A

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

23
Q

What does buffer solution contain

A

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

24
Q

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

A

K=1/Ka or Kb

25
Q

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

A

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

26
Q

What is buffer capacity

A

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

27
Q

How to depermine pH of a buffer solution

A

[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])

28
Q

What is pH of human blood

A

7.4

29
Q

What are buffer systems in human body

A

•carbonic acid/bicarbonate -H2CO3
•haemoglobin
•phosphate

30
Q

What is alkalosis and what is acidosis

A

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

31
Q

Give example on alkalosis and acidosis

A

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

32
Q

What is acid-base indicator

A

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

33
Q

In what amounts is H3O+ added

A

Small amounts

34
Q

Name some indicators

A

Methyl orange, bromethil blue, phenolphthalein

35
Q

Over how many pH units do colors change with indicators

A

Over 2pH units

36
Q

What is acid-base titration

A

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

37
Q

What is end-point of titration

A

When indicator changes color

38
Q

What is titration curve

A

Graphical representation of the pH of a solution during a titration

39
Q

What is equivalence point for strong acid and strong base

A

7

40
Q

What is equivalence point

A

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

41
Q

Whats unusual with titration of weak acid and strong base

A

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