Confusion of atomic mass vs atomic weight from book

[betterfuture]

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Please can someone explain to me the difference between atomic mass vs. Atomic weight. My Kaplan review says something while my chemistry book says another thing. I thought atomic mass is approximate to mass number(total # of neutrons and protons) while atomic weight was weighted average of isotopes.

 

[aldol16]

You're right - you get the idea. The two terms are often used interchangeably when we're not talking about nuclear processes because for most purposes, they are not different by any significant amount and we will usually be working with an isotopic mix anyway. The only time you should be careful with this is when you look at mass spectra and see peaks off by a couple units.

 

[betterfuture]

So is it right to say that atomic mass and atomic weight are the same, because that is what my chemistry book says.

 

[aldol16]

So is it right to say that atomic mass and atomic weight are the same, because that is what my chemistry book says.

For most purposes, yes.

 

[betterfuture]

Thank you.

 

[NextStepTutor_2]

For most purposes, yes.

For the purposes of the MCAT, you sure can, which is all that matters for test day.

good luck!

 

[betterfuture]

For the purposes of the MCAT, you sure can, which is all that matters for test day.

good luck!

Thank you.