How does diffusion limit affect reaction rate?
Diffusion-controlled (or diffusion-limited) reactions are reactions in which the reaction rate is equal to the rate of transport of the reactants through the reaction medium (usually a solution). Diffusion control is rare in the gas phase, where rates of diffusion of molecules are generally very high.
What is a diffusion limited reaction?
A diffusion limited reaction rate is one which depends solely on the rate at which solute molecules diffuse to the site of reaction such as the surface of a reactant particle.
How do you know if an enzyme is diffusion-controlled?
If the reactant molecules are such that subsequent events develop very rapidly when the reactants come into contact, the net rate of the reaction will be equal to the rate of diffusional encounter. The reaction is then said to be diffusion-controlled.
Why is the reaction rate of some enzymes higher than the diffusion rate?
The conceptually easiest case is that of a positively charged active site with a negatively charged substrate. The substrate (i.e. reactant) enters the active site with kinetics that are faster than diffusion because there is a long-range electrostatic interaction.
What affects the rate of diffusion?
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.
What does rate of diffusion mean?
The rate of diffusion, dn/dt, is the change in the number of diffusing molecules inside the cell over time. Since the net movement of diffusing molecules depends on the concentration gradient, the rate of diffusion is directly proportional to the concentration gradient (dC/dx) across the membrane.
What is the diffusion-controlled limit in an aqueous solution?
true or false: Both nonbiological catalysts and enzymes show reaction specificity. What is the diffusion-controlled limit in aqueous solution? Enzymes with a kcat/KM near the diffusion-controlled limit of 108 to 109 M-1s-1 are said to have achieved catalytic perfection.
Why does the rate of diffusion decrease over time?
The closer the distribution of the material gets to equilibrium, the slower the rate of diffusion becomes. Mass of the molecules diffusing: Heavier molecules move more slowly; therefore, they diffuse more slowly. The molecules slow down because they have a more difficult time getting through the denser medium.
Which of the following factors affect the rate of diffusion of gases?
The rate of diffusion depends on many factors like the concentration gradient, equilibrium of the system, temperature, mass of the particle, and many more. The medium in which the diffusion can be of three physical States.