2.5 Acids & Bases Flashcards

1
Q

What was the earlier definition of an acid?

A

Arrhenius

Acids release H+ when dissolved in water

Base releases OH- when dissolved in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the Bronsted-Lowry definitions of acids and bases?

A

Acid = H+ donor
Base = H+ acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does Lewis describe acids and bases?

A

Acids = electron pair acceptor
Base = electron pair donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the opinions on neutrality by the 3 acid base theories?

A

Arrhenius - Acids and bases can neutralise one another

Bronsted-Lowry & Lewis- Acids and bases can not reach neutrality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

3 Strong acid examples

A

HCl
H2SO4
HNO3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do strong acids do in solution?

A

Completely dissociate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Organic acid and bases are usually….

A

Weaker

Only partially dissociate in solution and form an equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the concentration of H+ or OH- ions released in strong acids and bases?

A

Same as concentration of starting acid or base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Acid + base =

A

Salt (+water)

In strong acids and bases, the base’s OH- is protonated by the H+ of the acid to produce water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When is water not produced in acid + base reactions?

A

When there’s weak acids or bases.

If base doesn’t contain a hydroxide, it can form a salt by accepting a proton. So water is not produced.

If base contains a carbonate or hydrogen carbonate, then CO2 is released.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a salt defined as?

A

The product of when you replace the proton component of an acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the difference between Bronsted-Lowry and Lewis?

A

Bronsted-Lowry describes the accepting or donating of a proton.

Lewis describes accepting or donating electron pairs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Get head around previous slide

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are conjugate acids and bases?

A

Species that act as acids or bases in the reverse direction of reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are conjugate pairs?

A

Species that are related but act as opposites (one as acid and other as base) on either side of the reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Learn Ka and Kb Equations

A

See pic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is pH a measure of?

A

Concentration of H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

pH =

A

pH = -log10 [H+]

eg. 1 × 10^-6 M = pH 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

pOH =

A

pOH = - log10[OH-]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Low pH =

A

Stronger acids
Ka and [H3O+] increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Higher pH =

A

Stronger bases
Kb and pH increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

pKw =

A

pKw = pH + pOH = 14

REMEMBER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is an indicator?

A

A weak acid molecule that changes colour with the change of equilibrium position

The indicator’s energy levels change significantly when it’s protinated 2hich changes its colour

24
Q

[H+] produced from a strong acid =

A

Starting concentration of the strong acid

In monoprotic acids

25
Who do u work out pH of a weak acid?
By working out the Ka
26
What is the 1st assumption used when calculating pH of a WEAK acid?
The only thing producing H+ is the dissociation of acid This means H+ = A-
27
What is the 2nd assumption used when calculating pH of a WEAK acid?
The acid dissociation is really small so... The starting concentration = equilibrium concentration
28
The amine group of an amino acid is...
A weak base
29
The carboxylic group of an amino acid is....
A weak acid
30
What does the degree of dissociation in an amino acid depend on?
The pH of the solution relative to their Ka
31
When pH < pKa
It's more acid Functional group more protonated than unprotonated
32
When pH = pKa
Functional group is 50/50 Protonated = unprotonated
33
When pH > pKa
The functional group is more deprotonated
34
Knowing if a molecule is ionised at a particular pH, allows a pharmacologist to predict...
How easily something is absorbed And how soluble it is (These are important properties for understanding the behaviour of a drug)
35
Learn graph shapes
See pic
36
What do buffers rely on? And what do they do?
They rely on le chateliers principle to maintain pH of a system against external change. This change can be addition of acids of bases
37
What are buffers formed from
Weak acids or weak bases
38
What does the buffer capacity of a solution depend on?
How much of the acid and how much of the conjugate base (HA and A-) you have present
39
What are buffers used for in labs?
To hold experiments at certain pH
40
How is the pH of a buffer calculated?
Using the Henderson Hasselbalch equation pH = pKa + log ([A-]/[HA])
41
Where is bicarbonate used as a buffer?
Lungs and kidney It buffers acids produced by metabolism and respiration
42
What is looked for in blood tests to check for Acidosis OR Akolosis?
pH of blood & Concentration of anions in the body's buffer system
43
What is the Haemoglobin buffer system in blood important for?
Carbon dioxide
44
What acts as buffer in intracellular fluid?
Amino acids of proteins can be protonated or unprotonated as a result of change in pH And phosphates
45
What is used as buffers in the kidney?
Ammonia Ammonium Phosphates Longer response period
46
What buffer systems are present in bones?
Inorganic components of skeleton are basic. A prolonged acidosis, will cause leaching of calcium and phosphates from skeleton
47
What maintains pH in the blood?
Bicarbonate in blood plasma Rapidly responding- dependant on amount of CO2 breathed out
48
What is the product of CO2 dissolving in water?
Carbonic acid, H2CO2
49
What can change the blood's pH?
Restricted exchange of CO2
50
What happens when too much CO2 is breathed out (hyperventilation) due to panicking?
H2CO3 is lost Blood becomes slightly Alkaline Can pass out as respiratory drive resets
51
What happens when breathing is restricted?
Too much CO2 Too much carbonic acid Too high a pH
52
Metabolic acidosis happens from?
Build up of other Acidic waste products
53
What can u get oalic acid from?
Poisoning Ingestion Metabolism of ethelene glycol
54
Diabetic keto acidosis signs
Very slow very deep breathing - to exchange more CO2
55
What parts of proteins can be protonated?
Haemoglobin and intracellular proteins (Histidine)
56
Which amine can be protonated?
Lysine It can form reversible bond with CO2 - this changes affinity of haemoglobin to transport O2