Lecture 7 - Solutions and Solubility - Chemistry & Physics of Anesthesia Flashcards
1
Q
What is a solution?
A
A solution is a solute dissolved in a solvent
2
Q
what is a suspension?
A
A suspension is when the solute DOES NOT dissolve in the solvent.
3
Q
What is a colloidal solution?
A
A colloidal solution is when particles exist in solution somewhere between a true solution and a true suspension.
4
Q
What is a solution?
A
A solution is when a solute completely dissolves in a solvent.
5
Q
What is a suspension?
A
A suspension is when the solute does not dissolve in the solvent.
6
Q
What is a colloidal solution?
A
A colloidal solution is when the particles exist somewhere between the solution and suspension state.
7
Q
What is the definition of a solution?
A
A solution is a homogeneous mixture of two or more components.
8
Q
What is the dissolving agent in a solution?
A
The solvent is the dissolving agent in a solution.
9
Q
What is the substance that is dissolved in a solution?
A
The solute is the substance that is dissolved in a solution.
10
Q
What are the types of particles in the solution?
A
Atoms, ions, molecules (sugar and water)
11
Q
Are the particles in suspension larger or smaller than those in solution or colloidal solutions?
A
The particles in suspension are larger than those in solution or colloidal solution.
12
Q
What is the dispersement of the particles in a suspension?
A
The particles in a suspension can be evenly distributed by mechanical means (i.e. shaking the contents), but eventually the particles will settle out (i.e. oil and water)
13
Q
Will particles settle out in a colloidal solution?
A
No! The size of particles in between those found in solutions and suspensions and can be mixed in such a way that they remain evenly distributed without settling out.
14
Q
What is the mixture of a colloidal solution called?
A
The mixture the particles form in a colloidal solution is called a colloidal dispersion. A colloidal dispersion consists of colloids in a dispersing medium (i.e. milk)
15
Q
What is a solvent?
A
A solvent is a substance in which a solute is dissolved.
- usually a liquid
- a solvent is the dissolving medium of the solute
16
Q
How does a solvent work to dissolve a solute?
A
The solvent particles surround the solute particles. The forming of a solution is physical process not a chemical one.
17
Q
Is forming a solution a physical or chemical process?
A
Forming a solution is a physical process, NOT a chemical one. The solvent particles are simply surrounding the solute particles.
18
Q
What is the universal solvent?
A
water is the universal solvent.
19
Q
What is the solvent in body fluids?
A
Water is the solvent in body fluids.
20
Q
What is a true solution?
A
A true solution is when the solute is completely dissolved in the solvent.
- this is a physical change
- solute can be a solid, liquid, or a gas
21
Q
What dictates the amount of solute dissolved in solvent?
A
Temperature dictates the amount of solute dissolved in a solvent.
22
Q
Will the solubility of a solid increase or decrease with increasing temp?
A
The solubility of a solid will increase with increasing temp
23
Q
Will the solubility of a gas increase or decrease with increasing temperature?
A
The solubility of a gas will decrease with increasing temperature.
24
Q
As the temperature increases will the solid become more or less soluble?
A
As the temperature increases, a solid becomes more soluble.
25
As the temperature increases will the gas become more or less soluble?
As the temperature increases, the gas becomes less soluble.
26
What determines how much solid solute is dissolved in a solvent?
Temperature, the amount of solid that dissolves in a solvent is usually directly proportional to the temperature.
- as the temperature increases, the solubility of the solid increases.
- as the temperature decreases, the solubility of the solid decreases.
27
What affects the solvents ability to dissolve solute?
The nature of the solvent affects the amount of solid that dissolves in the solvent.
28
What is a better solvent: water or ethanol?
Water is a better solvent than ethanol.
- water is more polar than ethanol
- water dissolves polar substances better than ethanol
29
As you increase the temperature, what happens to the solubility of glucose (solid)?
As you increase the temperature, the solubility of glucose increases because glucose is a solid.
30
What determines the solubility of a gas in a solvent?
The solubility of a gas in a solvent depends on the nature and the temperature of the solvent.
31
What is the relationship between increasing temperature and gas solubility?
As the temperature increases, the less gas that will dissolve in solution.
-the greater the temperature of the solvent (liquid), the less gas that will be dissolved in the solvent
32
What are the anesthesia implications of the relationship between temperature and gas solubility with increased temperature of solvent?
As the patients temperature increases, the gas solubility decreases. Therefore, as patient temperature increases the less anesthetic is dissolved and it is more difficult to anesthetize the patient.
(think: increased temperature = increased MAC requirement)
- as you increase the temp you decrease the partial pressure of the gas.
33
What are the anesthesia implications of the relationship between temperature and gas solubility with decreased temperature of solvent?
A the patients temperature drops, the more anesthetic is dissolved easier, the easier to anesthetize.
(think: decrease temperature = decreased MAC requirement)
- as you decrease the temp, you increase the partial pressure of the gas.
34
What is the relationship between gas solubility and temperature?
THE GREATER THE TEMPERATURE, THE LESS SOLUBLE THE GAS. THE GREATER THE TEMPERATURE OF THE SOLVENT, THE LESS GAS WILL BE DISSOLVED IN THE SOLVENT
35
Why is it that the increased temperature, causes a decrease in the amount of gas dissolved in the solvent?
The increased temperature, increases the KE of the gas molecules and breaks the IMF between the gas and solvent. Therefore, gas escapes from the solution.
-the increased KE with increased temp is the same reason for the increase in vapor pressure with increased temperature.
Bottomline: the greater the temperature, the less gas dissolved in the solute.
36
What is Henry's law?
The amount of gas dissolved in a liquid is directly proportional to the pressure applied to the gas as it overlies the liquid.
(think: of a hen sitting on eggs, giving the eggs pressure)
- the increase in pressure, the more gas dissolved in the liquid
- a decrease in pressure, the less gas dissolved in the liquid
37
According to Henry's Law, as the pressure applied to the gas layer increases, what happens to the solubility of the gas in the liquid?
As the pressure applied to the gas layer above the liquid increases, the solubility of the gas in the liquid increases.
38
According to Henry's Law, as the pressure applied to the gas layer above the liquid decreases, what happens to the solubility of the gas in the liquid?
As the pressure applied to the gas layer above the liquid decreases, the solubility of the gas in the liquid decreases.
39
What does Henry's Law state?
The amount of gas dissolved in a liquid is directly proportional to the pressure applied to the gas as it overlies the liquid.
(think: a hen sitting on eggs exerting a pressure on the eggs)
40
Is pressure applied to a gas directly or inversely proportional to gas solubility?
The pressure applied to a gas is directly proportional to gas solubility
- as the pressure applied increases, the gas solubility increases
- as the pressure applied to the gas decreases, the gas solubility decreases
41
Is temperature of the solvent directly or inversely proportional to gas solubility?
Temperature is inversely proportional to gas solubility.
- As the temperature of a solvent increases, the gas solubility decreases.
- As the temperature of a solvent decreases, the gas solubility increases.
42
What is a saturated solution?
The state of solution in which more solute cannot be added without some of the solute precipitating out of the solution (or vaporizing out of solution)
aka a saturated solution is one what the maximum amount of solute has been dissolved in the solvent and adding anymore solute to the solvent will just result in undissolved solute
43
What point is incorporated in a saturated solution?
the precipitation point is included in a saturated solution?
44
What is the saturated solution in terms of gases and liquids mixing?
The saturated solution is the point of equilibrium between the gas and liquid phase.
- the partial pressure of the gas = the partial pressure of the liquid
45
What is a super-saturated solution?
A super-saturated solution is one that holds more than it can hold.
46
What forms when you add more solute to a saturated solution?
a precipitate forms when you add more solute to a saturated solution.
47
For gases and liquids, what are the partial pressures of a saturated solution?
gas partial pressure = the liquid partial pressure.
| The point of equilibrium between the gas and liquid phases
48
What is solution strength?
Solution strength is the grams of solute/100 mL of solvent
49
What does % solution include?
grams of solute/100 mL of solution
50
What is the % solution of 0.9% NaCl?
0.9 grams NaCl/100 mL of solution
51
What is the % solution of D5W?
5 g dextrose/ 100 mL solution
52
What is molar solution?
Molar solution is moles of solute/1 liter of solvent
53
What is an example of molar solution using NaCl?
NaCl = 58 grams per mole. therefore 58 g NaCl/1 liter of solution = 1 molar solution
54
What would a 3 molar solution of NaCl be?
1 mole of NaCl = 58 grams. So a 3 molar solution would be 58 X 3 = 174 g NaCl solute /1 L solvent
55
What would a 0.3 molar solution of NaCl be?
1 mole NaCl = 58 grams. 0.3 moles of NaCl = 17.4 g so a 0.3 molar solution would be 17.4 g NaCl/ 1 L solvent
56
#moles solute/1 Liter solvent =
Molar Solution = # moles solute/1 L solvent
57
g solute/100 mL solvent =
% solution = g solute/100 mL solvent
58
Molar Solution =
moles solute / 1 L solvent
59
% solution =
grams of solute / 100 mL solvent
60
What is diffusion?
process whereby a substance spreads through the space available to it by random molecular motion
-diffusion is the random spread of molecules throughout a substance
61
In what direction does diffusion move?
Diffusion does from an area of high concentration to low concentration.
62
Molecular movement is a result of what type of gradient?
Molecular movement is a result of a pressure gradient.
63
What is a pressure gradient in terms of P1 and P2?
P1-P2 > 0 then there is a pressure gradient
64
What is the relationship between P1 and P2 for things to be moving?
P1 > P2 for things to be moving
65
What happens in terms of movement when P1=P2?
When P1=P2 then there is no movement.
66
What happens when P2 >P1?
there is a pressure gradient and things will be moving
67
What is Graham's Law as it relates to diffusion?
Graham's law for diffusion describes the movement of gas from one compartment to another through a porous membrane (diffusion) or small opening effusion)
68
Diffusion is the movement of particles through what?
Diffusion is the movement of particles through a membrane.
69
Effusion is the movement of particles through what?
Effusion is the movement of particles through a small opening.
70
What is the formula for Graham's law?
1/ square root of MW or 1/ square root of density
71
Is the relationship between molecular weight and diffusion directly or inversely proportional?
Inversely proportional - as molecular weight increases, diffusion decreases.
As molecular weight decreases, diffusion increases.
72
1/ square root of MW or 1/ square root of density is what law of diffusion or flow?
Graham's law is 1/sq. root of MW or 1/sq. root of density
73
Graham's Law of Diffusion including solubility
[solubility of gas 1/ sq. root MW gas 1] / [solubility gas 2/ sq. root gas 2] = diffusion rate of gas 1: diffusion rate gas 2
74
What is more soluble: CO2 or O2?
CO2 is much more soluble that O2 (22X times more soluble) so therefore CO2 will diffuse much more readily than O2 even though its molecular weight is bigger (44 vs 32) compared to O2.
75
What is Fick's Law?
Fick's Law describes the volume of a gas that diffuses across a membrane per minute
76
What is the formula for Fick's law?
Diffusion Rate = [(area) X (diffusion coefficient) X (P1-P2)] / (membrane thickness)
aka Fick's Law =
A X D X delta P/ T
Think: ADP like the sorority. ADP fucks for Fick's Law = A X D X delta P/ thickness.
because Fick rhymes with thick.
77
What is the diffusion coefficient?
Graham's Law is the diffusion coefficient, so
| solubility/ sq. root of MW = diffusion coefficient
78
Does diffusion increase or decrease with a thicker membrane?
Diffusion decreases as membrane thickness increases.
79
Does diffusion increase or decrease with a thinner membrane?
Diffusion increases as membrane thickness decreases.
80
What is the formula for diffusion rate and what is the name of this law?
Fick's Law = A X D X P/ thickness
| Think: ADP sorority fucks, and Fick rhymes with thick.
81
Fick's Law is...
Fick's law is A X D X P/thickness
| D = solubility / sq. root of MW
82
Bunsen Solubility Coefficient is
the volume of a gas in a unit volume of a liquid at 0 degrees C and 760 mmHg
-expressed as numerical value for a particular gas in a given liquid
83
Bunsen Solubility Coefficient is...
- the volume of gas in a unit volume of liquid at STP
84
What is STP?
0 degrees C (273 degrees Kelvin) and 1 atmosphere or 760 mmHg
85
The Bunsen coefficient for oxygen in water at STP is 0.049. What does this mean in volume %?
If the bunsen coefficient for oxygen in water at STP is 0.049 then that means there's 4.9 volumes of O2 per 100 mL H20 at STP
86
The Bunsen coefficient for oxygen in water at STP is 0.049. What does this mean in mL?
If the bunsen coefficient (the amount of gas dissolved per unit volume of liquid at STP) is 0.049 then there are 0.049 mL of oxygen dissolved per 1 mL of H2O.
87
The Bunsen Coefficient is...
the amount of gas dissolved in a liquid as STP. It is given as a number and that number is mL gas/ 1 mL solution.
88
What is the Ostwald Solubility Coefficient?
The Ostwald Solubility coefficient is the ratio of the volume of gas absorbed to the volume of solvent at the temperature and pressure of the experiment.
89
What is the Ostwald Solubility Coefficient as it applies to human physiology?
The Ostwald Solubility Coefficient as applied to human physiology are the "experimental conditions" with ambient pressure and body temperature.
90
What are the two pharmacological coefficients that relate to Ostwalds Solubility Coefficient?
Blood: Gas Solubility and Oil:Gas solubility are used to expressed Ostwald's solubility coefficient in the human body.
91
What is tension?
Tension is used to describes the concentration of a gas in a mixture. Tension is the force or pressure exerted.
92
What are the units of tension?
The units of tension are mmHg or cmH2O
93
What is surface tension?
Surface Tension is created at the ALI (air-liquid interface).
-created at the interface between a liquid and a gas where the liquid molecules are pulled together by IMF (cohesive forces)
94
In what direction do periphery molecules move d/t surface tension?
Periphery molecules move inward d/t surface tension.
95
Because of surface tension, does the volume tend to assume the largest or smallest area possible?
Surface tension causes molecules to assume the smallest area possible.
96
What shape do molecules form when they assume the smallest position possible?
Small volume tends to assume a spherical form.
97
Will surface tension occur is a molecule is surrounded completely by like molecules?
No! If there is a mutual attraction in all directions then there is no surface tension.
98
Is there surface tension when there is only mutual attraction at the sides and bottom only?
Yes! There is surface tension when there is only mutual attraction at the sides and bottom only.
99
What happens to surface tension when you add detergent?
Adding detergent breaks the surface tension and interrupts the polar attractions of water molecules.
100
What is surface tension?
- When a molecule is within the bulk liquid and is surrounded on all sides by other liquid molecules, which attract it equally in all directions, leading to a net zero force, there is no surface tension for that molecule.
- a molecule on the surface experiences a net attractive force pointing toward the liquid interior, because there are no molecules of the liquid above the surface. --> this is surface tension
101
What is the law of LaPlace?
The law of LaPlace defines the pressure gradient across the wall of a sphere (or cylinder) which are related to wall tension (surface tension) and radius
102
What does the law of LaPlace apply to?
The law of LaPlace applies to cylindrically shaped structures.
103
What is tension and how does it apply to the law of LaPlace?
tension is defined as the internal force generated by a structure.
104
What is the formula for tension?
Tension = pressure X radius
105
What is the law of LaPlace?
the pressure gradient across a sphere r/t surface tension and radius
106
Tension = Pressure X radius
Formula for tension
107
How does the Law of LaPlace apply to body systems?
The Law of LaPlace is present in:
1. blood vessels
2. left ventricle (dilated heart chamber)
3. normal alveoli (Pel, WOB)
4. Surfactant deficient alveoli (Pel, WOB)
108
Surface Tension, LaPlace Law, and the lung relationship
- surface tension has a big influence on Pel (compliance) and therefore WOB
- think of the alveolus as a sphere hanging from the airway
- LaPlace Law shows the relationship between pressure, radius, and tension of the sphere.
109
What is the formula for LaPlace law?
P = 2T / r
Pressure is in dynes/cm2
radius is in cm
tension is in dynes/cm
110
What is the formula for LaPlace alw?
P = 2T / r
(think: please I get tooty over ramen)
P= 2T/r
111
What causes surface tension in the alveolus?
the surface tension within the alveolus is a result of unbalanced water cohesive forces at the ALI
- since the surface tension of water is constant and not dependent on the area of the ALI, surface tension within the alveolus would be constant (if not for surfactant)
112
What is the law of LaPlace?
```
P = 2T/r
(Please I get tooty over ramen)
P= pressure inside the sphere
T= tension in the wall of the sphere (surface tension)
r=radius of the sphere
```
113
Is T in the Law of LaPlace a constant or does it change?
The T for tension in the law of LaPlace is a constant for spheres of similar composition.
So therefore we can say P = 1/r
114
As the radius increases, according to LaPlace's law the pressure increases or decreases?
As the radius increases, the pressure decreases.
115
As the radius decreases, according to LaPlace's law then pressure increases or decreases?
As the radius decreases, the pressure within the alveoli increases.
116
If we didn't have surfactant, the smaller the alveoli, the __________ the alveolar pressure.
If we didn't have surfactant, the smaller the alveoli, the greater the alveolar pressure.
117
What connects alveoli to one another?
smaller alveoli are connected to larger alveoli via common airways and collateral ventilation called Pores of Kohn
118
What are pores of Kohn?
Pores of Kohn are collateral ventilation pathways between alveoli.
119
LaPlace predicts that small alveoli will have a greater or smaller pressure than large alveoli?
LaPlace predicts that small alveoli will have a greater pressure than large alveoli.
120
Why is the fact that smaller alveoli have more pressure than larger alveoli when there is no surfactant a problem?
If smaller alveoli had a greater pressure than the larger alveoli than the air would flow from the smaller alveoli to the larger alveoli because pressure flows from high to low. Therefore, the smaller alveoli would empty into the larger alveoli and collapse.
- this collapse of smaller alveoli would increase the WOB.
121
In what pathological conditions do we lose surfactant? What does this do to the WOB?
ARDs, and drowning causes a loss of surfactant. When there is no surfactant then the small alveoli have a greater pressure than the larger alveoli. Therefore the small alveoli will empty into the bigger alveoli through the communal airways and the Pores of Kohn. This will cause the smaller alveoli to collapse and that will increase WOB.
122
Why do alveoli not collapse like LapLace's Law would lead us to believe?
Alveoli don't collapse because:
1. alveolar interdependence keeps the alveoli open.
2. surfactant changes the surface tension proportional to radius thereby reducing the surface tension more in small alveoli than large alveoli
- surfactant equalizes the pressure inside the alveoli of different sizes thereby stabilizing the alveoli
123
What is LaPlace's law?
P = 2T/ r
124
What is the take home message about surfactant?
Surfactant equalizes the pressure inside the alveoli of different sizes thereby stabilizing the alveoli.
-surfactant decreases the WOB by increasing the compliance of the lung and preventing alveolar collapse.
125
What is surfactant?
- surfactant is a detergent
| - dipalmitoylphosphatidylcholine
126
What produces surfactant?
type 2 alveolar cells
127
What is the job of surfactant?
surfactant decreases surface tension
- reduces the surface tension in small alveoli more than large alveoli (due to density)
- thus is equalizes the pressure within small and large alveoli
128
Surfactant changes what in response to what?
Surfactant reduces surface tension in response to changes in surface area.
129
When the alveoli gets larger, what happens to the surface tension?
If the same concentration of surfactant is present and spread over a larger surface area then the larger the alveoli surface area, the less well the surface tension is reduced.
130
If you have an increase in surfactant, you have a _________in surface tension.
If you have an increase in surfactant, you have a decrease in surface tension.
131
If you have a decrease in surfactant, you have a ____________ in surface tension.
If you have a decrease in surfactant, you have a increase in surface tension.
132
What is a micelle?
A micelle is an aggregate of surfactant molecules disbursed in a liquid forming a colloidal suspension.
