Which gas effuses slowest

The gases are allowed to exit the container through a tiny hole. Which gas will exit the hole the fastest? At a particular temperature, the average kinetic energy of all gaseous molecules is equal. Since hydrogen gas has the lowest mass out of these gases, it will have the highest average velocity. This means that it will exit out of the tiny hole at a rate faster than the other gases. Conversely, bromine, which has the most mass compared to the other gases, will exit the hole the slowest.

The rate of effusion for a gas is inversely proportional to the square-root of its molecular mass Graham's Law. Carbon dioxide:. Sulfur dioxide:. Molecule A has twice the mass of molecule B. A sample of each molecule is released into separate, identical containers. Which compound will have a higher rate of diffusion? According to Graham's law, the rate of diffusion of a gas molecule is inversely proportional to the root square of that molecule's mass.

Because molecule B has a smaller mass than molecule A, it will have a higher rate of diffusion. Suppose that after the pinhole is plugged, there are argon atoms in container B. Approximately how many neon atoms would you predict to be in container B?

By calling neon "gas 1" and argon "gas 2," we can compare the effusion rates of the two gases by plugging their molecular masses into the equation. This proportion is equal to the rate of neon effusion over the rate of argon effusion, giving the ratio of neon atoms to argon atoms in container B. As a result, atoms of neon gas will effuse out of the pinhole for every argon gas atoms.

Keep in mind that the heavier gas will effuse at a slower rate than the lighter gas; thus, we would expect there to be more neon than argon in container B. A 20cm tube holds two cotton balls, one in each end. The left cotton ball is saturated with undiluted HCl. The right cotton ball is soaked in an undiluted mystery compound. Vapors from the two cotton balls are allowed to mix within the tube.

Let us assume that the two compounds form a precipitate in the tube 6cm to the left of the right cotton ball. What is the molar mass of the mystery compound? This question is notably difficult, as it may not be immediately apparent what concept is being tested.

As the vapors of the compounds mix and react, we are able to establish the distance the each vapor has traveled from the cotton ball into the tube in the given amount of time. The tube is 20cm, and the reaction takes place 6cm from the mystery compound cotton ball. From this, we can establish that in an equal amount of time the HCl vapor traveled 14cm and the mystery compound traveled 6cm.

In order to solve this problem, we use Graham's law to compare molar masses to the rates of diffusion of the two gases. Since HCl moved 14cm to the right before interacting with the mystery compound, we know that the mystery compound moved only 6cm to the left. As a result, the diffusion ratio is 2.

Now, we need to find the square root of the inversed molar masses, which equals this diffusion ratio. So, the molar mass of the mystery compound is grams per mole.

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. 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. Under the same conditions, how long will it take 4. Solution It is important to resist the temptation to use the times directly, and to remember how rate relates to time as well as how it relates to mass.

Recall the definition of rate of effusion:. Note that this answer is reasonable: Since Ne is lighter than Xe, the effusion rate for Ne will be larger than that for Xe, which means the time of effusion for Ne will be smaller than that for Xe. Finally, here is one more example showing how to calculate molar mass from effusion rate data. What is the molar mass of the unknown gas?

Can you make a reasonable guess as to its identity? Check Your Learning Hydrogen gas effuses through a porous container 8. Estimate the molar mass of the unknown gas. Gaseous diffusion has been used to produce enriched uranium for use in nuclear power plants and weapons.

Naturally occurring uranium contains only 0. In a gaseous diffusion enrichment plant, uranium hexafluoride UF 6 , the only uranium compound that is volatile enough to work is slowly pumped through large cylindrical vessels called diffusers, which contain porous barriers with microscopic openings.

The process is one of diffusion because the other side of the barrier is not evacuated. The UF 6 molecules have a higher average speed and diffuse through the barrier a little faster than the heavier UF 6 molecules. The gas that has passed through the barrier is slightly enriched in UF 6 and the residual gas is slightly depleted. So the Ceo and the N. These will both both of these pairs will be the most challenging to separate by a fusion. And that is because they have similar molar masses and therefore similar effusion rights.

All right. And that finishes up this question. Thank you for watching. Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry deals with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds. Chemistry also involves understanding the properties and interactions of individual atoms and molecules for use in larger-scale applications.

In chemistry and physics, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles and objects that act as if they have both rest mass and volume.

However it does not include massless particles such as photons, or other energy phenomena or waves such as light or sound.

Matter exists in various states known as phases that are defined by various physical properties, such as state of matter, phase, shape, and density. The Standard Model of particle physics and the general theory of relativity describe fundamental particles and the fundamental forces acting between them that control the structure and dynamics of matter.

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