Question

Naturally occurring copper is composed of 69.17% of 63cu, with an atomic mass of 62.9296 u, and 30.83% of 65cu, with an atomic mass of 64.9278 u. Calculate the average atomic mass of copper. G

Answer 1

63.5456 amu

Solution:

Data Given:

Atomic Mass of ⁶³Cu = 62.9296 amu

Natural Abundance of ⁶³Cu = 69.17 %

Atomic Mass of ⁶⁵Cu = 64.9278 amu

Natural Abundance of ⁶⁵Cu = 30.83 %

Formula Used:

Average Atomic Mass = [(Atomic Mass of ⁶³Cu × Natural Abundance of ⁶³Cu) + (Atomic Mass of ⁶⁵Cu × Natural Abundance of ⁶⁵Cu)] ÷ 100

Putting values,

Average Atomic Mass = [(62.9296 × 69.17) + (64.9278 × 30.83)] ÷ 100

Average Atomic Mass = [(4352.8404) + (2001.7241)] ÷ 100

Average Atomic Mass = 6354.5645 ÷ 100

Average Atomic Mass = 63.5456 amu