Chemistry – Atoms, elements and compounds - Isotopes | e-Consult
Atoms, elements and compounds - Isotopes (1 questions)
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Solution:
The relative atomic mass (Ar) is calculated using the following formula:
Ar = Σ (Isotopic Mass × Isotopic Abundance)
We are given:
- Isotopic Mass (Carbon-12) = 12.000 amu
- Isotopic Abundance (Carbon-12) = 98.9% = 0.989
- Isotopic Mass (Carbon-13) = 13.001 amu
- Isotopic Abundance (Carbon-13) = 1.1% = 0.011
Therefore:
Ar(C) = (12.000 × 0.989) + (13.001 × 0.011)
Ar(C) = 11.868 + 0.143
Ar(C) = 12.011 amu
The relative atomic mass of carbon is 12.011.