A naturally occuring sample of copper consists of 69.2% of Cu63 and 30.8% of Cu65.The relative atomic mass of Cu63 is 62.93 and that of Cu65 is 64.93.Find the atomic mass of a naturally occuring sample of copper.
To find the atomic mass of a naturally occurring sample of copper, we'll use the percentage composition and the relative atomic masses of the isotopes Cu63 and Cu65.
Step 1: Convert the percentages to decimal form.
69.2% = 0.692 (Cu63)
30.8% = 0.308 (Cu65)
Step 2: Multiply the decimal form of the percentage by the relative atomic mass of each isotope.
(0.692) x (62.93) = 43.54 (Cu63)
(0.308) x (64.93) = 19.95 (Cu65)
Step 3: Add the calculated values for each isotope together.
43.54 + 19.95 = 63.49
Therefore, the atomic mass of a naturally occurring sample of copper is 63.49.