What type of unit is a mole

Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email. Anne Marie Helmenstine, Ph. Chemistry Expert. Helmenstine holds a Ph. She has taught science courses at the high school, college, and graduate levels.

Facebook Facebook Twitter Twitter. The abbreviation for mole is mol. One mole is exactly 6. The "particles" could be something small, like electrons or atoms, or something large, like elephants or stars. Featured Video. Cite this Article Format. Helmenstine, Anne Marie, Ph. What Is a Mole in Chemistry?

Avogadro's Number Example Chemistry Problem. Experimental Determination of Avogadro's Number. Scientists and engineers chemical engineers in particular sometimes measure amount of substance in units of gram-moles , kilogram-moles , pound-moles , or ounce-moles ; these measure the quantity of a substance whose mass in grams, kilograms, pounds, or ounces respectively is equal to its formula weight. The SI mole is identical to the gram-mole.

When the mole is used to specify the amount of a substance, the kind of elementary entities particles in the substance must be identified. The particles can be atoms , molecules , ions , formula units , electrons , photons or other particles. For example, one mole of water is equivalent to When the substance of interest is a gas , the particles are usually molecules.

An ideal gas has a molar volume of The name mole German Mol is attributed to Wilhelm Ostwald who introduced the concept in the year He used it to express the gram molecular weight of a substance. So, for example, 1 mole of hydrochloric acid HCl has a mass of Prior to both the IUPAP and IUPAC used oxygen to define the mole, the chemists defining the mole as the number of atoms of oxygen which had mass 16 g, the physicists using a similar definition but with the oxygen isotope only.

In the ICPM clarified the above definition, defining that the carbon atoms are unbound and in their ground state. As with other SI base units, there have been proposals to redefine the kilogram in such a way as to define some presently measured physical constants to fixed values.

One proposed definition of the kilogram is:. This number is the fixed numerical value of the Avogadro constant, N A , when expressed in the unit mol —1 and is called the Avogadro number.

The amount of substance, symbol n , of a system is a measure of the number of specified elementary entities. An elementary entity may be an atom, a molecule, an ion, an electron, any other particle or specified group of particles. Inverting this relation gives an exact expression for the mole in terms of the defining constant N A :.