Solutions and Solubility - week 7 Flashcards
Solution definition
solute dissolved in a solvent
Suspension definition
solution where the solute cannot be dissolved in the solvent
Colloidal solution definition
particles exist in solution somewhere between a true solution and a true suspension
Solvent
substance into which a solute is dissolved
True solution
occurs when solute is completely dissolved in the solvent (amount dissolved is dependent on temperature)
The greater the temperature of the solvent ____
the greater the amount of solid solute dissolved
When dissolving is endothermic then ___
increase solubility with increasing temperature
When dissolving is exothermic then ___
decrease solubility with increasing temperature
Does changes in our body temperature have an effect on solubility of solids in our body?
changes to body temperature are small and will have minimal effect on solubility
Concerning gases, the greater the temperature of the solvent the ___
less gas that will be dissolved in the solvent (liquid)
If patient’s temperature increases what happens to the anesthetic?
less anesthetic dissolved so more difficult to anesthetize
If patient’s temperature decreases what happens to the anesthetic?
more anesthetic dissolved so easier to anesthetize
How does gas escape from the solution with an increased temperature?
increased temperature –> more KE of the gas molecules –> breaks IMF between gas and solvent –> gas escapes
Saturated solution
state of a solution in which more solute cannot be added without some of the solute precipitating out of the solution (Point of equilibrium between the gas and liquid phase)
Solution strength- % solution
grams of solute/100mL solvent = % solution
example. .9% NaCl = .9 grams/ 100mL
Solution strength - molar solution
moles of solute per 1 liter of solvent
example. NaCl= 23+35 = 58 grams/mole
58grams NaCl/ 1 L of solvent = 1 Molar solution
diffusion
process whereby a substance spreads through the space available to it by random molecular motion (high to low concentration)
molecular movement is a product of ___
a pressure gradient
Henry’s Law
amount of gas dissolved in a liquid is directly proportional to the pressure applied to the gas as it overlies the liquid
Graham’s Law
movement of gas from one compartment to another thru a porous membrane
diffusion coefficient
(D) = Solubility of Gas/ square root MW
calculating relative rate of diffusion of 2 gases as they dissolve in a liquid
diffusion rate of gas 1/diffusion rate of gas 2 = sol gas 1/ sol gas 2 x square root of MW gas 2/MW gas 1
Which is less dense Helium or ethylene oxide?
helium is much less dense, the rate of effusion of helium thru a hole is greater than that of ethylene oxide
Fick’s Law
volume of a gas that diffuses across a membrane per minute
Bunsen solubility coefficient
volume of a gas in a unit volume of a liquid at 0 degree C and 760 mmHg
example: 4.9 volume of O2 dissolve in 100 mL H2O at 0C and 760mmHg = .049 of O2 dissolved in 1mL H2O
so bunsen coefficient for O2 in H2O at STP = .049
Ostwald Solubility coefficient
ratio of the volume of a gas absorbed to the volume of solvent at the temperature and pressure of the experiment
used to express the blood/gas: tissue/gas ratio
tension
concentration of a gas in a mixture, force or pressure exerted (cmH2O or mmHg)
surface tension
created at interface between liquid an gas where the liquid molecules are pulled together by intermolecular cohesive forces
- molecules drawn inward from periphery
- volume tends to assume smallest area possible
- small volume tends to assume spherical form
When a molecule is on the surface of a liquid what kind of force does it have?
a net attractive force pointing toward the liquid interior because there are no molecules of the liquid above the surface
Law of laplace
pressure gradient across the wall of a sphere which are related to wall tension and radius
law of laplace applied to cylindrically shaped structures
T = P x r
two applications: blood vessel (aneurysm), left ventricle (dilated chamber)
law of laplace applied to spherically shaped structures
P = 2 x T / r
two applications: normal alveoli (lung elastic recoil and wob), surfactant deficient alveoli (Pel and wob)
is surface tension within the alveolus constant?
yes d/t surfactant, unbalanced water cohesive forces at the ALI but surface tension doesn’t depend on the area of the ALI
according to laplace’s law if the radius is small
the pressure within the sphere is increased
Why would having a pressure gradient and small alveoli emptying into larger ones be a problem for ventilation?
bad for gas exchange because the alveoli would collapse requiring much force to inspire
per laplace law if there was no surfactant
then smaller alveoli have a higher alveolar pressure
surfactant
reduces wob by increasing the compliance of the lung and preventing alveolar collapse
surfactant
detergent (dipalmitoylphosphatidylcholine), produced by Type 2 alveolar cells, reduces alveolar surface tension (more in small than larger so it equalizes the pressures)
poiseueille’s law
describes laminar flow
F = pi r^4 delta P/ 8 n L
Flow is directly proportional to
r^4 (radius) and delta P (pressure gradient/change in pressure)
Flow is indirectly proportional to
n (viscosity) and L (length)
poiseueille’s law to resistance
R = 8 n L/ pi r^4
resistance is inversely proportional to
r^4
resistance is directly proportional to
n and L
lower gauge needle does what to flow (r^4)?
increases
shorter need length does what to flow (L)?
increase
increased hydrostatic pressure does what to flow (delta P)?
increases
polycythemic patient has what kind of blood flow (n)?
decreased (want to hydrate and warm sickle cell disease patients)
anemic patient has what kind of blood flow (n)?
increased
reynolds number
predicts when flow through a tube changes from laminar to turbulent
reynolds number is directly proportional to
fluid velocity, tube diameter, fluid density
reynolds number is inversely proportional to
viscosity
what happens when reynolds number is >2000
flow changes from laminar to turbulent
flow becomes turbulent if
velocity is high
tube narrows or has kinks/angles
wall of tube is rough
fluid flows thru an orifice
resistance to flow ____ when flow becomes turbulent
increases
