# chemistry

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Copper has two naturally occurring isotopes. Cu-63 has a mass of 62.939 amu and relative abundance of 69.17%. Use the atomic weight of copper to determine the mass of the other copper isotope.

• chemistry -

fraction*mass + fraction*mass = atomic mass Cu.
You know fraction and mass of one isotope. Th fraction of the second isotope is 1.00-fraction of first, and the periodic table gives you the atomic mass Cu. Solve for mass of second.

• chemistry -

Is this for webassign? Cause I had that exact same problem lol does all of the USA use webassign?
Just wondering

• chemistry -

well, I live in Indiana, West Lafayette and I am not sure all of the USA use webassign, and yes this is webassign

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