The mean free path is the average distance a molecule travels between collisions. The mean free path increases with decreasing pressure; in general, the mean free path for a gaseous molecule will be hundreds of times the diameter of the molecule. In general, we know that when a sample of gas is introduced to one part of a closed container, its molecules very quickly disperse throughout the container; this process by which molecules disperse in space in response to differences in concentration is called diffusion shown in Figure 1.
The gaseous atoms or molecules are, of course, unaware of any concentration gradient, they simply move randomly—regions of higher concentration have more particles than regions of lower concentrations, and so a net movement of species from high to low concentration areas takes place. In a closed environment, diffusion will ultimately result in equal concentrations of gas throughout, as depicted in Figure 1. The gaseous atoms and molecules continue to move, but since their concentrations are the same in both bulbs, the rates of transfer between the bulbs are equal no net transfer of molecules occurs.
We are often interested in the rate of diffusion , the amount of gas passing through some area per unit time:.
The diffusion rate depends on several factors: the concentration gradient the increase or decrease in concentration from one point to another ; the amount of surface area available for diffusion; and the distance the gas particles must travel. Note also that the time required for diffusion to occur is inversely proportional to the rate of diffusion, as shown in the rate of diffusion equation.
A process involving movement of gaseous species similar to diffusion is effusion , the escape of gas molecules through a tiny hole such as a pinhole in a balloon into a vacuum Figure 2.
Although diffusion and effusion rates both depend on the molar mass of the gas involved, their rates are not equal; however, the ratios of their rates are the same. If a mixture of gases is placed in a container with porous walls, the gases effuse through the small openings in the walls. The lighter gases pass through the small openings more rapidly at a higher rate than the heavier ones Figure 3.
This means that if two gases A and B are at the same temperature and pressure, the ratio of their effusion rates is inversely proportional to the ratio of the square roots of the masses of their particles:.
Using the same apparatus at the same temperature and pressure, at what rate will sulfur dioxide effuse? Effusion Time Calculations It takes s for 4. What does the rate of diffusion of a gas depend on? Why would o2 effuse faster than CO2 in the same room? What gas diffuses four times as fast as oxygen? Does hydrogen diffuse 4 times faster than oxygen?
What is the relationship between a gas molecular weight and speed of effusion? Which of the following gas will have lowest rate of diffusion? What is rate of diffusion in chemistry? At what temperature is a gas likely to have the lowest rate of diffusion? This makes sense, because larger gases will move more slowly compared to lighter gases.
The rate of effusion of a gas is inversely proportional to the square root of the molecular weight of the gas. The lighter a gas is, the faster it will effuse; the heavier a gas is, the slower it will effuse. Of all the choices, helium He has the lowest molecular weight atomic weight in this case , so it will have the highest rate of effusion.
Gas A has a molar mass that is times greater than that of Gas B. Which of these gases would be expected to effuse through a small hole faster? By how much? Gas A effuses times faster than Gas B. Gas B effuses times faster than Gas A. In order to answer this question, let's start by considering what effusion is and what things affect it.
Effusion is the movement of a gas through a tiny hole that separates two different spaces. Because the gas particles move around in random directions with an average speed that is dependent on the temperature of the sample, lighter gas particle will move faster than heavier gas particles. This is because at a given temperature, all gas particles in a sample will have the same average kinetic energy. Consequently, we would expect gas particles with a higher molar mass to effuse more slowly than gases with a lower molar mass.
This means that Gas B should effuse faster than Gas A. The next step is to actually calculate how much greater Gas B effuses compared to Gas A. To do this, we'll need to use the following equation:. Since we know that Gas A is times heavier than Gas B, we can plug this into the equation to solve for the ratio of Gas B's rate of effusion to that of Gas A.
Therefore, Gas B effuses times faster than Gas A. The correct answer is that Oxygen gas will effuse 4 times slower than hydrogen gas. If you've found an issue with this question, please let us know. With the help of the community we can continue to improve our educational resources. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.
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Possible Answers: Container B will contain twice as many argon atoms as neon atoms. The partial pressure for argon is greater than the partial pressure for neon in container A. Container B will contain twice as many neon atoms as argon atoms. Both gases will have equal partial pressures in container A. Correct answer: The partial pressure for argon is greater than the partial pressure for neon in container A.
O2 and CO2 do not react under ordinary conditions, owing to the thermodynamic stability of CO2 and the large activation energy required for multiple double-bond cleavage.
How is carbon dioxide removed from the blood? Carbon dioxide is removed by the bloodstream by the lungs. The cellular respiration process generates carbon dioxide.
How are oxygen and carbon dioxide carried in the blood? Oxygen enters the blood from the lungs and carbon dioxide is expelled out of the blood into the lungs. The blood serves to transport both gases. Oxygen is carried to the cells. Carbon dioxide is carried away from the cells. How fast does gas diffuse? Can gas diffuse inside a liquid? Diffusion in liquids: Diffusion in liquids is slower than that in gases.
This is because the particles in liquids move slowly as compared to the particles in gases. The carbon dioxide and oxygen gas present in air diffuse into water, and dissolve in it. Can solid diffuse into gas?
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