011 g 1 mol of o 602214 1023 o atoms 159994 g and so

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Unformatted text preview: 2.011 g 1 mol of O = 6.02214 * 1023 O atoms = 15.9994 g, and so on. ▲ Most elements are composed of mixtures of two or more isotopes so that the atoms in a sample of the element are not all of the same mass but are present in their naturally occurring proportions. Thus, in one mole of carbon, most of the atoms are carbon-12, but some are carbon-13. In one mole of oxygen, most of the atoms are oxygen-16, but some are oxygen-17 and some are oxygen-18. As a result, The weighted-average atomic mass of carbon was calculated on page 48. KEEP IN MIND that molar mass has the unit g> mol. FIGURE 2-17 One mole of an element The watch glasses contain one mole of copper atoms (left) and one mole of sulfur atoms (right). The beaker contains one mole of mercury atoms as liquid mercury, and the balloon, of which only a small portion is visible here, contains one mole of helium atoms in the gaseous state. *Atomic mass (atomic weight) values in tables are often written without units, especially if they are referred to as relative atomic masses. This simply means that the values listed are in relation to exactly 12 (rather than 12 u) for carbon-12. We will use the atomic mass unit (u) when referring to atomic masses (atomic weights). Most chemists do....
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This note was uploaded on 11/20/2012 for the course CHEM 1000 taught by Professor Hempstead during the Fall '09 term at York University.

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