# Homework Help: Correct definition of Relative atomic mass

1. Sep 11, 2011

### synkk

1. The problem statement, all variables and given/known data
Explain what you understand by the term Relative Atomic Mass

The question is equal to three marks, though i don't think i've put enough for all the marks:

3. The attempt at a solution

The mass of an atom relative to one atom of carbon-12.

I would think thats only equal to one mark, how do i get the other three?

2. Sep 11, 2011

### cmb

So carbon-12 has a relative atomic mass of 1 (unity) then (viz, relative to itself)?! I'd not give you the one mark! :/

3. Sep 11, 2011

### synkk

So how could i get receive the three marks?

4. Sep 11, 2011

### synkk

I put: Average mass of an element compared to 1/12th of a carbon-12 atom? Hows that

5. Sep 11, 2011

### Staff: Mentor

Not bad, but not completely correct either. Relative atomic mass can be relative to any atom, doesn't have to be C-12 - the choice is arbitrary. It was oxygen in the past, it is C-12 now.