Element Oxygen Essay Peer Editing Essays
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.
What is invariably used (except for sample calculations in chemistry textbooks; see below!
Second, 12 is an important number in the English system of weights and measures, so the definition of a dozen as 12 things makes sense.
However, the choice of the unusual number, 6.022 x 10 is used, it is necessary to resurrect an older, in some ways more sensible and useful, definition of the mole, which is grounded in the atomic weight scale addressed above.
Because the atomic weight scale is numerically preserved in the definition of gram atomic weights, the mass of 1 gram-atomic weight of any element could be immediately determined as the atomic weight in grams.
Thus 1 gram-atomic weight of sulfur weighs 32.06 g; 1 gram-atomic weight of hydrogen weighs 1.008 g, and so on.
The mole is useful whether or not we know how many atoms of carbon-12 there are in 12.000 g of carbon-12.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.This is a very useful correpondence, but it was discovered only after the weight scale had been in use for a long time.In their desire to be able to count atoms by weighing, chemists gradually developed the concept of the "gram-atomic weight", which was defined in exact correspondence with the atomic weight scale: 1 atom of C weighs 12.000 g Thus the gram-atomic weight of an element was defined as the atomic weight of the element, expressed in grams.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.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 atomic mass unit is a very tiny unit of mass appropriate to the scale of single atoms.Originally, of course, chemists had no idea of its value in laboratory-sized units like the gram.