Diffusion and FICK's Laws - How fast does mass transfer proceed without flow

there a gentleman welcome to physical chemistry 1 1 my name is Dr. Nobel to date but the question how fast is mass transit without external to low that they're going to talk about the diffusion

there are basically 2 different types of transfers with transport but if you do this is called convection and the transport without exception though that is called the conduction transfer without the how can the image is intended to explain phenomena on the left hand side there's a container was high energy in the all the right hand side where the container with is is given in blue to get if you connect it to continue when the gasses will mix freely without any out of you will spontaneously move for that and hydrogen will spontaneously me to the rock not because of an external though but just because of the concentration grain another example of the

key consider the preparation of the team on the left hand side

initially pure water on the right hand side it just hit key there the concentration gradient of ingredients quit ingredients removes spontaneously from right to left by the the concentration

brought lines as follows on the left hand side in the water low concentration on the right hand side and the very a high concentration and a concentration gradient in between this gradient is here's the wild boar on might also be cut and with the

conduction the completion of conductive transport that lie FIL last density is proportional to the gradient is deeper than gradient and the fact that the province the gradient is given by

the sea you over the next for 1

dimensional process change in concentration per disk the rate

of transport is described by the lost and to in this case the motor lost and the the number of moles that quaternary 80 per unit time the and over the FIL tendencies proportional to the concentration gradient the proportionality factor is the diffusion constant do you have to mathematical

convention and negative sign of new trackpad proceeds to reduce the negative slope of the curve and this is the 1st law of diffusion it where the rate of diffusion is proportional to this notion of concentration not sample the OnLive stationary she this you were the gradient the CODA is the same everywhere and that means that will be the matter said the INS flowing from left to right A-Z everywhere at the same speed this also means that the gradient does not change over time that have a lot of diffusion

coefficient in the he is a measure of how fast use inverse at a given gradient these dependent both on the species that and metrics in which users in liquid phase in water about the diffusion is rare in his little the magnitude of 50 years about 10 to the negative 9 meters square set in gasses however diffusion received significant her in creating and gasses with long exclusively about station without generating new moving the US and media hydrogen in that diffuse about 10 thousand times faster than a than there were the

interestingly we can calculate the the diffusion coefficients of gasses using the kinetic theory again with the energy loss at virtuosity and the mean free path that the fact of you also your gas particles and if you were a kid I have all gas particles the fact that the knee

this can at the minute that column dioxide being is known about the particle would use lower than hydrogen infected coup Ishant of the EU to was by the the 5 smaller than the hydrogen the movement dye-diffusion which is described by its long was explained by the model of a random walk by Einstein and small they write the

random motion of a particle in a matrix that and came to the named after them the greatest quite simple or the left hand side there the mean is placement X square the distance of particle moves by diffusion on average on the right hand side of the integration there's time and it usually costs the displacement times and has to be square so the individuals placement acts that threaten wanting would average out to 0 in an isotropic match that had displacement of sugar molecules in water that issue but after 1 2nd but what is it only moved about 100 microns from starting point by the and we have to wait a long time and the particles that even with spread of Chico about 10 by following certain so the so-called macroscopic

systems infusions of various their grows and only too slow for efficient Mexico the situation is different however Apple microscopic systems in a biological cell or the mixture by fusion the received the vitamins It's a couple

out of the water completely at the mixing by fusion will take out

efficient mixing in macroscopic systems require connection require that all macroscopic organisms would have a few lows system to provide convective currents for the concentration for file can use speaks 1st law to calculate the rate of diffusion we right hand side there is a high concentration of that side the low concentration it we know almost linear increase in concentration at the center at about 6 centimeters the diffusion is a factor as I know this because remember moment last density is proportional the negative of this good married is the rock wild and that indeed those calculated the flux density alternatively if you know them all that who make candidates the diffusion cottage by the way this that

often non-stationary things whereas the the Connes burned vendor and it flattens out to the art of this time the concentration broke why we change this changes quantitatively described by Fick's 2nd law the curvature

of the concentration brought by determines the increase or the decrease of contemplation with time the change in concentration

the feeling T is proportional to the 2nd derivative he the quality and the the curvature of the graph at the point of maximum curvature if a and we accept the greater changes in concentration if coaches opposed

to the colors convex cliches the concentration will increase time that curvature negative concave shape a conservation will give a group with with the courage of being the euro at the center of this brought by concentration of this pond would not in summary a concentration gradient provokes diffusion the rate of the universe the proportional to the slope of concentration br the concentration change of a nonstationary diffusion is proportional to the curvature of power its 1st loan for with these equations to makes recommendation brought by all the time

but initially the concentration brawl will flatten out more and more over eventually diffusion come to a halt where the broth was completely words of that summer of

diffusion mass-transport without some though the concentration gradient why the rate of diffusion is proportional to this notion of a concentration brought by this peaks 1st