Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Sturm88 on September 12, 2008, 12:09:21 AM
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Chromium has four main isotopes.
50Cr, 52Cr, 53Cr, and 54CR
50Cr- 4.43% relative abundance 49.946 Isotopic Mass
52Cr- ? % relative abundance 51.941 Isotopic Mass
53Cr- ? % relative abundance 52.946 Isotopic Mass
54Cr- 2.28% relative abundance 53.939 Isotopic Mass
Average Mass = 51.996
Determine the two unkowns.... really stumped could use some help.
I know how to do the simple 65Cu, 63Cu with the 1-x but I just don't know how to put this one into an equation.
I suppose using two variables may be the key but I just don't know how to arrange it.
51.996= (51.941x)+((x-y)52.947)+(2.28*53.939)+(4.43*49.946)
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hello sturm88
you can choose to set up two variables or just one variable. You need to always define your variables x and y first.
let x% be the relative abundance of Cr-52 and y% be the relative abundance of Cr-53
Can you rearrange your working based on the above definition? One more equation to form is that x+y = 100 - 4.43 - 2.28
Alternatively, you can set up one variable x only. like let x% be the relative abudance of Cr-52, therefore the relative abundance of Cr-53 is (100-4.43-2.28-x)%, whichever way you feel comfortable with.
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Thank you.