Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

2nd yr- CSA- Nutrition and Periodontal Disease > Nutrition and erosion > Flashcards

Nutrition and erosion Flashcards

1
Q

Describe the physical structure of water

A

It is a tetrahedral structure with intermolecular hydrogen bonds between + hydrogens and - oxygens

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

What do neutron and x ray scatter suggest about oxygen in water?

A

Suggests there’s a high possibility of finding oxygen jatos 2.8A apart from each other

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

How far apart in nm are oxygen atoms from each other in water

A

0.28NM

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

What determines the structure of liquid ice?

A

Hydrogen bonds

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

What is the 0.28nm distance between oxygens in water dependent on?

A

Weakly dependent on temperature

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

Name soem intermolecular forces

A
  1. Hydrogen bonding
  2. Dipole Dipole
  3. Van der Waals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens when a solvent eg LiCl is added to water?

A

The soft breaks apart and the Li+ ion attracts the oxygen causing the oxygen of water to arrange in a tetrahedral war around Li+

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

What effect do polar molecules have on water?

A

They have a disordering effect on liquid water structure

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

Why is water important?

A

It constitutes about 70% of mass of most living things

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

Is water polar or on polar?

A

Polar

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

Describe the ionisation of water and what it yields

A

Water can undergo REVERSIBLE ionisation to yield H+ and OH-

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

How is the degree of ionisation of water at equilibrium represented?

A

KeQ=
[H+][OH-]/
[H2O]

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

Describe the relationship between the total concentration of H+ and OH-?

A

The total concentration of H+ and OH- is constant, an increase in one ion concentration is
compensated by a decrease in the concentration of the other ion

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

What does table salt dissolve into in water?

A

NaCl-> Na+ +Cl-

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

Equilibrium favours which reaction in the dissolution of table salt?

A

Favours the forward reaction (In favour of dissolution)

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

What would happen if we put a tooth in water?

A

It would dissolve in a reversible reaction:

Ca(PO4)6OH2 -> 10Ca2+ + 6PO4 3- + 2OH-

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

What happens to weak acids in water?

A

They partially ionise (dissociate) in water

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

When is equilibrium reached?

A

When the forward and reverse reaction of a chemical equation are equal

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

What does the Ka tell us?

A

Tells us the degree of dissolution

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

What is the equilibrium constant (acid dislocation constant Ka) GIVEN by for acetic acid ?

A

Ka= [H+][CH3COO-]/

[CH3COOH]

21
Q

What is the equilibrium constant (acid dislocation constant Ka) GIVEN by for HCL?

A

Ka= [H+][Cl-]/

HCL

22
Q

Describe the general relationship between pKa and acid strength?

A

pKa is smaller for stronger acids and larger for weaker acids

23
Q

What is the relationship between pH and hydrogen ion concentration?

A

pH= -log[H+]

24
Q

What is the relationship between pKa and Ka?

A

pKa= -logKa

25
Q

What effects the erosive potential of a drink or food?

A
  1. ph
  2. Titratable acidity (major factor)
  3. Presence of chelators
  4. Frequency, flow rate of how a drink is drug
  5. Bottle design ie if you are drinking from a cap or straw
  6. Saliva flow
  7. Cohesion of the drink to the enamel surface
26
Q

What happens when you eat carbohydrates

A

They are fermented to produce acid

27
Q

What happens to the acid produced by the bacterial fermentation of carbohydrates on the mouth?

A

Initially H+ is buffered in the plaque and saliva.

But as pH reduces the fluid medium is depleted of OH- and PO4 3- and these react with H+ to form H2O and PO4 2-

28
Q

State the value of the critical pH of the oral cavity?

A

5.5

29
Q

State Le Chatelier’s principle

A

If a chemical system at equilibrium experiences a change in concentration, temperature, volume, or partial pressure then the equilibrium shifts to counteract the imposed change and a new equilibriumis established

30
Q

How does chemical erosion occur?

A

Can occur by the hydrogen ion derived from acids as they disassociate in water

31
Q

How does H+ cause damage?

A

The H+ can attack the mineral by directly dissolving and combining with phosphate

32
Q

Go through the mechanism of dissolution of enamel by cheating agents

A
  1. Ca10(PO4)6(OH)2 -> 10Ca+ +6PO4 3- + 2OH-
  2. 6PO4 3- + 6H+ -> 6HPO4 2-
  3. 6PO4 2- + 6H+ -> 6H2PO4-
  4. 6H2PO4- + 6H+ -> 6H3PO4 (strong acid)
33
Q

What happens to all acids in aqueous solutions

A

All acids ionise in aqueous solutions to give:

HA -> A- + H+

34
Q

Give the KA for a general acid HA

A

Ka = [A-][H+]/[HA]

35
Q

What does a small pKa mean?

A

It means the acid has a large Ka so theres a large amount of A- and H+

36
Q

If an acid has a small pKa describe its Ka and is it a weak or strong acid?

A

It has a large Ka and so is a strong acid

37
Q

What does a large pKa mean?

A

It means the acid has a small Ka so theres a small amount of A- and H+

38
Q

If an acid has a small pKa describe its Ka and is it a weak or strong acid?

A

It has a small Ka and so is a weak acid

39
Q

State the Henderson Hasselbach Equation

A

pH = pKa + log ([A-] /[HA])

40
Q

What is special about the half was point of acid titration

A

It is the point where pH=pKa

41
Q

What is the stabile constant?

A

It is represented as K

It is used to measure the strength of interactions

42
Q

What do high values of logK indicate?

A

A stronger bond

43
Q

What happens as the pH of a drink increases?

A

Its acid erosion potential decreases and its chelation potential increases

44
Q

Go through the steps of demineralisation and demineralisation

A
  1. Acid attack drops the oral pH from 7 to 4.5
  2. Calcium and phosphate dissolve increasing local concentration
  3. Salivary buffering takes pH back to 7
  4. Solution is again supersaturated and minerals can form on the crystal surface
  5. If fluoride is preset fluoroapatite can form
    which is less soluble than hydroxyapatite or enamel.
45
Q

What can we add to acidic drinks to reduce erosive attack?

A

We can add calcium and phosphate

46
Q

What happens when you aadd calcium to a drink

A

The drink moves towards supersaturation and the calcium also neutralises the chelating effect by binding to citrate

47
Q

What happens to a tooth as soon as it erupts?

A

A salivary pellicle forms on the surface

48
Q

What are the benefits of having salivary pellicles?

A

They form a diffucito barrier and protect the outer surface of the tooth from direct acid attacks thus slowing down erosion

2nd yr- CSA- Nutrition and Periodontal Disease (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions