Why does avogadros law work

Connect and share knowledge within a single location that is structured and easy to search. Why is Avogadro's law always true? How and why do equal volumes of gases at equal pressure and temperature contain equal number of molecules?

I know it is a fundamental principle in chemistry but I wonder how it works. In kinetic theory, the pressure exerted by an ideal gas point-like, non-interacting particles, elastic collisions depends on the rate at which momentum is exchanged with the walls of any container as the molecules bounce off them. The momentum is of course proportional to the molecule's speed and mass, but the rate at which molecules hit a wall additionally depends on how fast they are going and how many molecules there are in the volume of gas.

If you put that together you find that pressure depends on the number of molecules in a volume of gas and how much kinetic energy each molecule has. The final step is to understand that the average kinetic energy of molecules in an ideal gas depends only on their temperature. Thus a gas of a given temperature and number of molecules per unit volume will always exert the same pressure in ideal circumstances. Or to turn this around, a gas of a given pressure and temperature will contain the same number of molecules per unit volume.

Well, it's not always true — it's an approximation that breaks down at high pressures or at low temperatures where many gases turn into liquids or solids. But if the mean distance between gas molecules is many, many, many times longer than the size of the molecules themselves, so that the molecules are effectively "noninteracting," then it no longer matters what species the molecules are or how they would interact if they could.

Flipping that over we find that each atom is alone in a volume of roughly 37 nm 3 , a cube about 3. Worked example: Using the ideal gas law to calculate a change in volume.

Practice: Calculations using the ideal gas equation. Derivation of gas constants using molar volume and STP. Avogadro's law. Gas mixtures and partial pressures. Worked example: Calculating partial pressures. The Maxwell—Boltzmann distribution. Dalton's law of partial pressure. Next lesson. Current timeTotal duration Oops, that is a picture of John Dalton, not Avogadro! Google Classroom Facebook Twitter. Video transcript Voiceover: So continuing the history of the ideal gas equation here.

We get to the 19th century with an Italian chemist name Amedeo Avogadro. Amedeo spent a bit of his time experimenting with tiny particles.

In honor of his experiments, the number of particles in one mole of something was named Avogadro's Number which is approximately 6. One thing that Avogadro postulated was that equal volumes of gas at the same temperature and pressure contain equal number of particles whether those particles are atoms or molecules.

For instance, if you filled up four balloons to exactly one liter at 25 degrees Celsius with different gases, so let's have a green balloon, and we can say that this green balloon is argon, and we'll have a pink balloon, and I'll try to make it the exact same size as the previous one, and we'll say it's nitrogen. Use the molecular formula to find the molar mass; to obtain the number of moles , divide the mass of compound by the molar mass of the compound expressed in grams.

The carbon C atom has six protons and six neutrons in its nucleus. In imprecise terms, one AMU is the average of the proton rest mass and the neutron rest mass.

Avogadro's number , N A , is the fundamental physical constant that links the macroscopic physical world of objects that we can see and feel with the submicroscopic, invisible world of atoms. In theory, N A specifies the exact number of atoms in a palm-sized specimen of a physical element such as carbon or silicon. Definition of Avogadro's number. Converting between molecules and moles is done by either multiplying by or dividing by Avogadro's number: To go from moles to molecules, multiply the number of moles by 6.

To go from molecules to moles, divide the numbers of molecules by 6. However, Dalton rejected Avogadro's hypothesis because Dalton believed that atoms of the same kind could not combine. Since it was believed that atoms were held together by an electrical force, only unlike atoms would be attracted together, and like atoms should repel.

Why does Avogadro's law work? Category: science chemistry. Avogadro's Law actually states that the volumes of ideal gases at a fixed temperature and pressure are proportional to the number of molecules that are present. This means that putting more particles in the same size container at the same temperature increases the outward pressure on the container walls. What is Avogadro's law example? What is the unit of Avogadro's number? What does Dalton's law state?

A small particle is like a sports care it may not have much for mass but it has a very fast velocity. The velocity squared makes up for the small mass. Why does Avogadro's principle hold true for gases that have large particles and also for gases that have small particles? Chemistry Gases Avogadro's Law. David Drayer.