3.1.12- Acids and Bases Flashcards

1
Q

What is a brønsted Lowry acid

A

Proton donor

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2
Q

What is brønsted Lowry base

A

Proton acceptor

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3
Q

What is a brønsted Lowry reaction

A

Reaction involving the transfer of a proton

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4
Q

What is a monoprotic acid

A

Acid that released one H+ ion per molecule

Eg HCl,HNO3

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5
Q

What is a diprotic acid

A

Acid that release two H+ ions per molecule

Eg H2SO4

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6
Q

Definition of ph

A

PH = -log(H+)

[H+] = 10^-pH

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7
Q

What is Kw

A

Kw=[H+][OH-]

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8
Q

What is Kw value

A

1.00x10-14

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9
Q

Effect of temperature on Kw

A

As temperature increases the equilibrium moves right to oppose increase in temperature
So [H+] and [OH-] increases
Kw increases and pH decreases

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10
Q

How to find ph of strong bases

A

[H+] = Kw/ [OH-]

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11
Q

Find ph of mixture of strong acid and strong based

Excess H+

A
Mol H+ 
Mol OH- 
Xs mol H+ 
Xs [H+] =n/v 
pH= -log[H+]
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12
Q

Find ph of mixture of strong acid and strong based

Excess OH-

A
Mol H+ 
Mol OH- 
Xs mol OH- 
Xs [OH-] = n/v 
[H+] = Kw/[OH-] 
-log[H+]
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13
Q

What is a weak acid or base

A

Only partially dissociated

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14
Q

Acid dissociation constant

A

Ka= [H+][A-]
—————
[HA]

pKa=-logKa

Ka= 10^-pKa

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15
Q

What does a bigger value of Ka mean or smaller value of pKa mean

A

A strong acid

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16
Q

Find pH of weak acid

A

Ka=[H+]^2
———
[HA]

pH=-log[H+]

17
Q

Reactions of weak acids

XS HA

A

1) mol of OH- left and A- formed
2) [HA] left over [A-] left
3) use Ka to find [H+]
4) find pH

18
Q

Reactions of weak acid

Xs OH-

A

1) [OH-]
2) Kw to find [H+]
3) find pH

19
Q

Reactions of weak acids when mol HA =OH-

A

pH= pKa of weak acid

20
Q

What is an indicator

A

Weak acids were HA and A- are different colours
Low pH HA present more
High pH A- present more

21
Q

What is methyl orange

A

When Red more HA
When yellow more A-
Changes at 3.2-4.4

22
Q

What is phenolphthalein

A

More HA is colourless
More A- is pink
Changed between 8.2-10.0

23
Q

What does equivalence point show

A

Where moles of alkali = moles of base

24
Q

What is an end point

A

Where the indicator changes colour

25
Q

Show what ph graph with weak acid base and strong acid base

A

Draw

26
Q

How to calculate pH of buffer when acid added

A
A-+H+ —-> HA 
Mol H+ added 
Work out [HA] and [A-] left
Ka= [H+][OH-] 
        —————-
            [HA] 
-log[H+]
27
Q

How to calculate pH of buffer when base added

A

Mol OH-
HA+ OH- —> A- + H2O
[HA] and [A-]

Ka = [H+] [A-]
————
[HA]
pH = -log[H+]

28
Q

What do buffer depend on

A

Ratio of HA to A- when small amount of acid or alkali added this does not change very much

29
Q

What is an acid buffer made from

A

Weak acid and salt of weak acid

30
Q

What is base buffer made out of

A

Weak base and salt of weak base