chemistry and physics Flashcards
ionic bond
complete transfer of valence electrons. leaves one atom with negative charge and one atom with positive charge. common with acids and bases.
covalent
equal sharing of valence electrons. single bond is created when one pair of electrons is shared. double bond is created when two pairs of electrons are shared.
polar covalent
unequal sharing of valence electrons. favor one atom over another still.
ex) water. region where oxygen is relatively negative and region near the hydrogen is relatively positive.
what resides in the nucleus
protons and neutrons
number of _________ in the nucleus decides the atomic number
protons
what keeps the electrons from “flying away”
the positive charge of the nucleus attracts the negative charge of the electrons
an atom will have a neutral charge if
number of electrons = number of protons
van der waals
very weak intermolecular force that holds the same types of molecules together
molecular bonds in decreasing order of strength
covalent > ionic > polar covalent > van der waals
which law is represented by this image?
daltons law of partial pressure
total pressure is equal to sum of partial pressure of each gas in the mixture
how to convert total partial pressure to volumes percent for a liquid
volume of solute/volume of solution x 100
how to convert a total partial pressure to volumes percent for a gas
partial pressure/total pressure x 100
how to convert volumes percent to partial pressure
volumes % / 100 x total pressure
practice question: at sea level, the agent monitor measures the end tidal iso at 8mmHg. convert this to volumes percent
(8/760) x 100 = 1% sevo
practice question: at sea level, the agent monitor measures the end tidal sevoflurane at 2%. what its he total partial pressure of sevo in exhaled Vt?
(2/100) x 760 = 15.2mmHg
or just .02x760
henrys law
at constant temperate, the amount of gas that dissolves in a solution is directly proportional to the partial pressure of the gas over the solution
which component of the oxygen delivery system is MOST affected by henrys law?
PaO2
how does partial pressure affect solubility
increased pp increases solubility
decreased pp decreases solubility
how does temperature affect solubility
increased temperature decreases solbulity
decreased temperature increases solubility
ex of application: anesthetic emergence is prolonged in hypothermic patient
what is the purpose of the solubility coefficient and what is O2/CO2’s solubility coefficient
represents how easily gas can be put into a solution
O2: 0.003 mL/dL/mmHg
CO2: 0.067 mL/dL/mmHg
how to calculate amount of CO2 dissolved in blood
CO2 x 0.067
which equation represents real application of henrys law that we use
O2 delivery equation
what is ficks law of diffusion and real world applications
transfer rate of gas through a tissue medium
applications: diffusion hypoxia, severe COPD (reduced alveolar surface area and therefore slower rate of induction), calculation of CO, drug transfer across placenta)
rate of transfer (ficks law of diffusion) is directly proportional to
partial pressure difference (driving force)
diffusion coefficient (solubility)
membrane surface area
rate of transfer (ficks law of diffusion) is indirectly proportional to
membrane thickness
molecular weight
define grahams law and application
molecular weight of gas can determine how fast it diffuses through a membrane
- rate of diffusion is inversely proportional to the square foot of the gases weight
application: second gas effect (using N2O to hasten onset of a volatile anesthetic
high FGF is turbulent as it passes through annular space (determined by gas’ density)
define boyles law
Px V
constant: temperature
variable: pressure, volume
inverse relationship
define charles’ law
V/T
constant= pressure
variable: temperature and volume
direct relationship
define gay lussacs law
P/T
constant: volume
variable: pressure, temperature
direct relationship
real world applications of boyles law
P x V
-diaphragm contraction increases Vt
-pneumatic bellows
-squeezing bag valve mask
-using bourdon pressure gauge to calculate how much O2 is in a given cylinder
real world application of charles’ law
V/T
LMA cuff ruptures when placed in autoclave
real world application of gay lussacs law
P/T
O2 tank explodes in heated environment
ideal gas law
unifies all 3 gases into a single equation
Pv=nrT
P= pressure V=volume n= number of moles r= constant 0.0821 liter-atm/k/mole T= temperature
define ohms law
current passing through conductor is directly proportional to voltage and inversely proportional to resistance. helps understand fluid flow.
ohms law can be found in these familiar hemodynamic terms (3)
Poiseuilles Law
Q=BF
R=radius
change in P= AV pressure gradient (Pa-Pv)
n=viscosity
L=length of tube
how does temperature affect viscosity and resistance
increased temperature decreases viscosity and resistance
decreased temperature increases viscosity and resistance
reynolds number equation
laminar flow being determined by gas viscosity is related to which law
poiseuilles law
laminar flow being determined by gas density is related to which law
grahams law
describe laminar flow and real world examples
all molecules travel in parallel pattern (<2,000)
molecules in the center of the tube travel at the fastest rate while the molecules near the walls of the tube travel at the slowest rate
examples: air flow in terminal bronchioles, BF in systemic circulaiton
describe turbulent flow and real world examples
chaotic flow. usually produced by: orifice (change to a narrow diameter), high gas flow, acute angle in tube (>25 degrees), branching in the tube
examples: flow through glottis or annular space when FGF is high, flow through angles (air flow through medium sized bronchi)
2 ways to improve airflow
have patient breathe lower density gas
use of heliox (useful for patient with epiglottitis)
describe transitional flow and real world examples
turbulent pattern in center of tube and laminar pattern near walls of tube
which physical principle applies to operation of a jet ventilator
bernouilles principle and venturi effect
define bernoullis principle
relationship between pressure and velocity of a moving fluid
if the fluids velocity is high, pressure exerted on walls of tube will be low
if fluids velocity is low, pressure exerted on walls of tube will be high
ex) as width of tube suddenly becomes smaller, fluid in constricted region must move faster to achieve given distance in certain time frame
define venturi effect
application of bernoullis principle
as airflow in tube moves past point of constriction, pressure at constriction decreases (bernoulli). if pressure in tube falls below atmospheric pressure, then air is entrained in the tube.
ex) jet ventilator, venturi mask, nebulizer
define coanda effect
describes how a jet flow attaches itself to a nearby surface and continues to flow along that surface when the surface curves away from the initial jet direction
ex) wall hugging of mitral regurgitation and water that follows the curve of glass
what is the law of law place equation for a cylinder shape and examples
what is the law of laplace equation for a spherical shape and examples
law of laplace and the left ventricle
helps us understand the afterload of myocardial stress
intraventricular pressure: force that pushes the heart apart
wall stress: force that holds the heart together
you can see from this equation that wall stress can be reduced by decreased IVP or radius and increased wall thickness
the risk of ionizing radiation exposure to the anesthesia provider is
inversely proportional to the square distance f the source
yearly maximum radiation exposure for adults (and pregnant)
5 rem
.5 rem or .05 rem/month
3 ways to limit radiation exposure
distance (>6ft)
duration
shielding
practice question: during a surgical procedure with fluoro, the patient receives 40mR at a distance of 1 foot from the radiation source. how much radiation will the anesthesia provider receive if she stands 5ft from radiation source?
intensity 1 = distance 2 / intensity 2 = distance 1
intensity 1=40mR
intensity 2=x
distance 1=1ft
distance 2=5ft
=1.6mR
define latent heat of vaporization
number of calories required to convert 1g of liquid to vapor without a temperature change in the liquid
define critical temperature
highest temperature in which gas can exist as a liquid aka temperature above which a gas cannot be liquified no matter how much pressure is applied to it
define evaporation
process where compound transitions from liquid state to gaseous state at a temperature below its boiling point
define boiling point
vp= atmospheric pressure
requires an open container
increased patm=increased BP
specific heat
amount of heat required to increase temperature of 1g of substance by 1 degree c
apply latent heat of vaporization to the inhalational gas in the vaporizers (and how modern vaporizers compensate)
anesthetic liquid in vaporizer exerts vapor pressure inside vaporization chamber. means some exists as liquid, some exists as gas
fresh gas flows over anesthetic liquid, carrying with it some of the agent that exists in the gas phase
this cools the remaining liquid which reduces the VP of the liquid and therefore fewer anesthetic molecules enter the gas phase
modern vaporizers compensate for this temperature change by using metals with high thermal conductivity, use temperature compensation valve, and for des direct heat is applied to anesthetic liquid
define adiabatic process
occurs without gain or loss of energy. very rapid expansion or compression of gas where there is no transfer of energy
ex) joule thompson effect
define joule thompson effect
gas stored at high pressure that is suddenly released escapes from its container into a vacuum. quickly loses speed as well as significant amount of kinetic energy resulting in fall in temperature.
ex) explains why O2 cylinder that is opened quickly feels cool to the touch
ex) rapid compression of gas intensifies kinetic energy, causing temperature to rise.
2 gases that exist as liquids in their cylinders
N2O and CO2
because critical temp of both is higher than room temp (room temp ~20c)
critical temperature of common gases
N2O
CO2
O2
air
Nitrogen
N2O 36.5c (liquid inside tank)
CO2 31c (liquid inside tank)
O2 (-119c)
air (-140c)
Nitrogen (-147c)
kelvin
melting point of water
boiling point of water
designed so 0k is absolute zero where all molecular movement stops
melting point of water: 273k
boiling point of water 373k
celsius
melting point of water
boiling point of water
based on behavior of water
melting point of water: 0c
boiling point of water: 100c
converting between kelvin and celsius
because both operate in intervals of 100 its relatively easy
kelvin = 273 + c
celsius = k - 273
farenheit to celsius
C=
= (F - 32) x 5/9
melting point for celsius is 100 and Fahrenheit is 180. therefore the ratio 1:8 is based on number of degrees between melting point on each side. 180: 100 = 1:8/ 1 or 9/5. we use the ratio backwards when converting to celsius
celsius to Fahrenheit
F=
= (C x 1.8) + 32
melting point for celsius is 100 and Fahrenheit is 180. therefore the ratio 1:8 is based on number of degrees between melting point on each side. 180: 100 = 1:8/ 1 or 9/5.
1 atmosphere =
mmHg
torr
bar
kPa
cm H2O
lb/inch^2
760 mmHg
760 torr
1 bar
100 kPa
1,033 cm H2O
14.7 lb/inch^2
1mmHg = ______ cmH2O
1.36cmH2O
1cmH2O = ____ mmHg
0.74mmHg
avogadros number
1 mole of any gas is made up of 6.023 x 10^23 atoms
1 mole of gas is equal to the molecular weight of that gas in grams
molecular weight of helium and 1 mole
molecular weight: 4
1 mole: 4g and contains 6.023 x 10^23 atoms
molecular weight of O2 and 1 mole
atomic weight 16
O2 is diatomic, so the molecular weight is 16 x 2 = 32g
1 mole: 32g and contains 2x (6.023 x 10^23) atoms
