Medical Sciences 4100F/G Study Guide - Mole Fraction, Molar Mass, Chemical Formula
15 Sep 2013
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Isotopes are atoms with the same number of protons (so they are the same element) but with different numbers of neutrons. This different number of neutrons results in identical elements having different mass numbers: barium is element number 56. In a neutral atom, the number of electrons is equal to the number of protons, so this species has 56 electrons. The mass number of any element is the sum of the number of protons and the number of neutrons. Use the average atomic mass (from the periodic table) to determine the atomic mass of xga, using the equation to determine a weighted average. (p. a-4) Atomic mass of xga = 70. 93, therefore the mass number of xga is 71: the molar mass of a compound tells us the mass of one mole of the compound. Molar mass = 114. 97 gmol 1: 1 mole of c2h6o molecules contains 2 moles of c atoms.
