1. Determine the element's average atomic mass number using the periodic table of the elements. This will be a number with several decimal places behind it. This value is the average
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How do you calculate percent abundance of an isotope? You find the isotope number and then you calculate that into a fraction and then turn the fraction into a percentage and divide
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Pretend that you have a 100. g sample of rubidium. 27.8 g would be Rb87 27.8 g/(87 g/mol) = 0.31954023 mol 72.2 g would be Rb85 72.2 g/(85 g/mol) = 0.849411765 mol Total mass is
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To calculate percent change use this formula: Percent Change = New Value  Old Value ' Old Value x 100. That is to say percent change equals the new value minus the old value divided
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