Said what I wanted to say above ...
Please can someone help with with this calculation for atomic mass Watch
- 29-09-2016 20:32
- 29-09-2016 20:33
- 29-09-2016 20:39
Relative atomic mass = ((isotope number X abundance)+(isotope number X abundance)) / 100
The abundance is the percentage
So, in your case:
(63 X 69) + (65 X 31) / 100 = 63.62
It is best to try to round your numbers to 3 significant figures, unless the question specifies otherwise, so in this case the answer would be 63.6. However, 63.62 would probably still give you full marks in the exam.