Who is avogadros number

Medical Definition of Avogadro's number. Get Word of the Day daily email! Test Your Vocabulary. Test your knowledge - and maybe learn something along the way. Love words? Need even more definitions? Just between us: it's complicated. For example, the mean molecular weight of water is This property simplifies many chemical computations.

If you have 1. Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:. Skip to main content. Video transcript - [Instructor] In a previous video, we introduced ourselves to the idea of average atomic mass, which we began to realize could be a very useful way of thinking about a mass at an atomic level, or at a molecular level. But, what we're gonna do in this video is connect it to the masses that we might actually see in a chemistry lab.

You're very unlikely to just be dealing with one atom, or just a few atoms, or just a few molecules. You're more likely to deal with several grams of an actual substance. So, how do we go from the masses at an atomic scale to the masses, masses of samples that you see in an actual chemistry lab, or in, I guess you could say, r-scale of the world. Well, the chemistry community has come up with a useful tool. They said, all right, let's think about a given element.

So, say, lithium. We know its average atomic mass is 6. What if there were a certain number of atoms of lithium such that if I have that number, so times certain, certain number of atoms, then I will actually end up with 6. And, this number of atoms is 6. So, if you have a sample with this number of lithium atoms, that sample is going to have a mass of 6. Whatever its average atomic mass is in terms of unified atomic mass units, if you have that number of the atom, you will have a mass of that same number in terms of grams.

Now, you might be saying, is there a name for this number, and there is indeed a name, and it is called Avogadro's number, named in honor of the early 19th century Italian chemist, Amedeo Avogadro. And, in most contexts, because you're not normally dealing with data with this many significant digits, we will usually approximate it as 6.

Now, there's another word that it's very useful to familiarize yourself with in chemistry, and that's the idea of a mole. Now, what is a mole? It is not a little mark on your cheek. It is not a burrowing animal. Actually, it is both of those things, but, in a chemistry context, a mole is just saying you have this much of something. The first rough estimate came courtesy of physicist Robert Millikan, who measured the charge of an electron.

The charge of a mole of electrons, called a Faraday , was already known by the time Millikan made his discovery. Dividing a Faraday by the charge of an electron, then, gives us Avogadro's number. Over time, scientists have found new and more accurate ways of estimating Avogadro's number, most recently using advanced techniques like using X-rays to examine the geometry of a 1 kilogram sphere of silicon and extrapolating the number of atoms it contained from that data.

And while the kilogram is the basis for all units of mass, some scientists want to begin using Avogadro's number instead, much the way we now define the length of a meter based on the speed of light instead of the other way around. You probably won't get the day off work or find your local drugstore flush with cards celebrating the occasion, but Mole Day is celebrated every year by chemists throughout the world.

Since Avogadro's number is 6. Revelers tell chemistry jokes, blow bubbles of natural gas that they set ablaze, toast with drinks chilled by dry ice and even recite the mole pledge of allegiance. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Physical Science.