To calculate the relative atomic mass of copper, you need to consider the masses and relative abundances of its isotopes. Given that copper-63 (^63Cu) contributes 69.09% and copper-65 (^65Cu) contributes 30.91%, we can calculate the relative atomic mass as follows:
Relative Atomic Mass = (Mass of ^63Cu x Relative Abundance of ^63Cu) + (Mass of ^65Cu x Relative Abundance of ^65Cu)
The atomic masses of copper-63 and copper-65 are approximately 62.9296 atomic mass units (u) and 64.9278 u, respectively.
Using the given abundances, the calculation becomes:
Relative Atomic Mass = (62.9296 u x 0.6909) + (64.9278 u x 0.3091)
Relative Atomic Mass = 43.5512 u + 20.0477 u
Relative Atomic Mass ≈ 63.5989 u
Therefore, the relative atomic mass of copper, considering the abundances of copper-63 and copper-65, is approximately 63.5989 atomic mass units.