In practice, we seldom need to know how many atoms or molecules we are working with, so in mole calculations the number 6.022 x 10 is rarely used.Tags: Clock HomeworkGraphic Design Business Plan TemplatePublisher Of An Essay Concerning Human UnderstandingEssay Questions For American HistoryFrench Essay TechniquesFlorida State Essay
Analogous terms, such as gram-molecular weight for the molecular weight of a compound expressed in grams, were similarly used.
However, having to use a different term depending on whether elements or compounds were being discussed was awkward and inconvenient.
The early versions of the atomic weight scale were established by scientists who had no knowledge of the electron, proton, or neutron.
When these were discovered in the late 19th and early 20th centuries, it turned out that the mass of an atom on the atomic weight scale was very nearly the same as the number of protons in its nucleus.
For this reason, the term "mole" was adopted to signify the atomic, molecular, or formula weight of a pure substance expressed in grams.
Alternative definition of the mole: O, weighs 46.069 g. If we mix 46.069 g of ethyl alcohol with 18.015 g of water, we can be assured that the mixture contains 1 molecule of ethyl alcohol per molecule of water.This is not worrisome, because neither number is crucial to the utility of the mole. It is used to represent the mass of a single atom, molecule, or formula unit of a substance, in which case it has units amu/atom.It is also used to represent the mass of a mole of substance, in which case it has units g/mole.This is true because 1 mole of substance contains N, we can make the following statements: 1 molecule of glucose contains 6 atoms of C, 12 atoms of H, and 6 atoms of O; 1 mole of glucose contains 6 moles of C atoms, 12 moles of H atoms, and 6 moles of O atoms; 10 molecule of glucose contains 60 atoms of C, 120 atoms of H, and 60 atoms of O; 10 moles of glucose contains 60 moles of C, 120 moles of H, and 60 moles of O atoms; Any amount of glucose contains equal numbers of C and O atoms, and twice this number of H atoms; Any amount of glucose contains equal numbers of moles of C and O atoms, and twice this number of moles of H atoms. moles Fe = 10.0 g Fe x 1 mole/55.85 g = 0.1791 moles moles S = moles Fe = 0.1791 g S = 0.1791 moles S x 32.06 g S/mole = 5.71 g S : Hemoglobin is the oxygen-carrying protein of most mammals.Each molecule of hemoglobin contains 4 atoms of iron.If we weigh one mole of iron and one mole of sulfur, we know that these two samples contain the same number of atoms. How many atoms there are in a mole is of subsidiary importance.Nonetheless, it has become possible to determine this number. We thus see that this number is simply a consequence of the choice that 1 mole be the formula weight in grams.The mole enables us to count atoms in the laboratory.The mole is useful whether or not we know how many atoms of carbon-12 there are in 12.000 g of carbon-12.It is nearly analogous to defining a dozen as the mass of a substance that contains the same number of fundamental units as are contained in 733 g of Grade A large eggs.This definition completely obscures the utility of the dozen: that it is 12 things! The mole is the same kind of unit as the dozen -- a certain number of things. First, the number of things in a mole is so huge that we cannot identify with it in the way that we can identify with 12 things.