Section 6: Mass
Atomic Mass Unit, Average Atomic Mass, Avogadro's Number, Molar Mass, Mass Conversions
Is it possible for us to count individual atoms? Because we are unable to look at a group of atoms together and determine how many atoms there are, it is important that we be able to count atoms by massing them. When counting by massing, we need to take into account the different isotopes that each element has. The instrument by which we have been able to determine the percentage of each isotope is a mass spectrometer. With this instrument we have been able to measure the amount of each isotope of an element. There is quite an exhaustive list on ptable.com (click the tab at the top labeled isotopes and select an element). Avogadro's number plays a large role when calculating the number of atoms in a particular sample, it is imperative that you not only remember the number but are able to perform mathematical operations using scientific notation. Essentially molar mass is the mass of one mole of a compound. It is a conversion factor that can be found on the periodic table. This conversion factor is used to change between the mass of an element with the number of atoms.
Is it possible for us to count individual atoms? Because we are unable to look at a group of atoms together and determine how many atoms there are, it is important that we be able to count atoms by massing them. When counting by massing, we need to take into account the different isotopes that each element has. The instrument by which we have been able to determine the percentage of each isotope is a mass spectrometer. With this instrument we have been able to measure the amount of each isotope of an element. There is quite an exhaustive list on ptable.com (click the tab at the top labeled isotopes and select an element). Avogadro's number plays a large role when calculating the number of atoms in a particular sample, it is imperative that you not only remember the number but are able to perform mathematical operations using scientific notation. Essentially molar mass is the mass of one mole of a compound. It is a conversion factor that can be found on the periodic table. This conversion factor is used to change between the mass of an element with the number of atoms.