How does diffusion change over time?
As time passes, diffusion changes the distribution of molecules until the concentration gradient essentially vanishes. The true driving force for diffusion is differences in chemical potential, which is a thermodynamic property. Molecules diffuse from regions of higher to lower chemical potential.
Therefore, the rate of diffusion of a gas is inversely proportional to both time and square root of molecular mass. It is also inversely proportional to the square root of density. But it is directly proportional to pressure.
The molecules slow down because they have a more difficult time getting through the denser medium. If the medium is less dense, diffusion increases.
Time refers to length of time until the introduction and an individual or firm adopts a new product/service. The more discontinuous the innovation and the less product/service communication; the longer the time for the new product/service to diffuse.
Time-dependent diffusion coefficients arise from anomalous diffusion encountered in many physical systems such as protein transport in cells. We compare these coefficients with those arising from analysis of stochastic processes with memory that go beyond fractional Brownian motion.
The greater the difference in concentration, the quicker the rate of diffusion. The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly. The greater the surface area, the faster the rate of diffusion.
The temperature affects the rate of diffusion. As the temperature increases, particles gain more kinetic energy and so can diffuse across a membrane more quickly. Therefore, as the temperature increases, the rate of diffusion increases.
Typically, reaction rates decrease with time because reactant concentrations decrease as reactants are converted to products. Reaction rates generally increase when reactant concentrations are increased.
Diffusion of substances plays an important role in cellular transport in plants. The rate of diffusion is affected by the concentration gradient, membrane permeability, temperature, and pressure. Diffusion takes place as long as there is a difference between the concentrations of a substance across a barrier.
Diffusion is rapid over very short distances, and slow over longer distances.
Does diffusion work over long distances?
Diffusion as a Transport Mechanism
Diffusion is very efficient over short distances and does not require energy. As such it is used in a variety of body systems where gradients and membranes suited to it are found. However over large distances diffusion is very slow.
Diffusion occurs more quickly in gases than in a liquid because the particles in gases move very quickly in all directions whereas the particles in liquids move slowly as compared to the gas particles.
The time for diffusion is linear in y/x for 3 dimensions; proportional to log(y/x) for 2 dimensions; and independent of y/x for 1 dimension. For example, when y/x = 0.1 (e.g., target diameter 1 nm, diffusion distance 10 nm), q3 = 0.35 and q2 = 1.22.
In diffusion, the time to diffuse across a distance is given by , so that time to diffuse increases with the square of distance (consequence of Fick's Second Law).
Beyond that, diffusion is too slow, and a larger organism would starve. In other words, essentially all living organisms larger than around 1 mm rely on fluid flow or some other sort of directed motion, either motion they generate themself, or in the environment (such as a water current).
The rate of diffusion is affected by the concentration gradient, membrane permeability, temperature, and pressure.
Simple passive diffusion occurs when small molecules pass through the lipid bilayer of a cell membrane. Facilitated diffusion depends on carrier proteins imbedded in the membrane to allow specific substances to pass through, that might not be able to diffuse through the cell membrane.
The molecular diffusion coefficient is caused by the random thermal motion of molecules in a gas or liquid and depends on the temperature and pressure, molecular properties, such as mass and volume, and the forces between molecules.
The higher the temperature, the higher the kinetic energy of particles. As temperature increases, rate of diffusion will increase. The greater the difference in concentration on either side of the membrane, the greater the rate of diffusion.
- extent of the concentration gradient. greater the difference in concentration, the more rapid the diffusion. ...
- mass of the molecules diffusing. ...
- temperature. ...
- solvent density. ...
- solubility. ...
- surface area and thickness of the plasma membrane. ...
- distance travelled.
Which of the following would increase the rate of diffusion?
If temperature is increased, the rate of diffusion increases.
With an increase in temperature, the particles gain kinetic energy and move faster. The actual average speed of the particles depends on their mass as well as the temperature – heavier particles move more slowly than lighter ones at the same temperature.
Diffusion is fastest through gases, followed by liquid, then plasma, and lastly, solids. In chemistry, diffusion is defined as the movement of matter by the random motions of molecules.
Reaction Time Defined
In other words, the lapse of time between stimulus and the beginning of the response or said another way, the interval of time between application of a stimulus and detection of a response. It is our ability to detect, process and respond to a stimulus. 1.
Many factors have been shown to affect reaction times, including age, gender, physical fitness, fatigue, distraction, alcohol, personality type, and whether the stimulus is auditory or visual.