CHEM 1AL Lecture Notes - Lecture 2: Molecular Geometry, Molar Mass, Molecular Mass
18 Feb 2016
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Avogadro"s number is the number of atoms or molecules present in a sample with a mass, expressed in grams, numerically equal to its atomic or molecular mass expressed in amu"s or daltons. It is defined as the number of 12c atoms in exactly 12 grams of 12c, or 6. 02 1023 carbon atoms in a mole of carbon-12. Some of the more than twenty different types of experiments used to determine. Avogadro"s number utilize methods for directly counting the number of molecules present in a sample of a compound with known mass. This is the type of experiment that you will perform. Under appropriately controlled conditions, it is possible to spread a film of a fatty substance only one molecule thick, a monolayer, onto a water surface. The thickness of the monolayer can be calculated from the measured volume of substance required to make the monolayer and the measured area of the surface that is covered.
