Answer:
Isotope N–14 = 99%
Isotope N–15 = 1%
Explanation:
Let isotope A be N-14
Let isotope B be N-15
From the question given above, the following data were obtained:
For isotope A (N-14):
Mass of A = 14
Abundance of A = A%
For isotope B (N-15):
Mass of B = 15
Abundance of B = (100 – A%)%
Atomic mass of nitrogen = 14.01 amu
Thus, we can obtain the relative abundances of the naturally occurring isotopes of nitrogen as illustrated below:
Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100]
14.01 = [(14 × A%)/100] + [(15 × (100 – A%)/100]
14.01 = 0.14A% + 0.15(100 – A%)
14.01 = 0.14A% + 15 – 0.15A%
Collect like terms
14.01 – 15 = 0.14A% – 0.15A%
– 0.99 = – 0.01A%
Divide both side by – 0.01
A% = – 0.99 / –0.01
A% = 99%
Abundance of B = (100 – A%)%
Abundance of B = (100 – 99)%
Abundance of B = 1%
Thus, the relative abundances of the naturally occurring isotopes of nitrogen are:
Isotope N–14 = 99%
Isotope N–15 = 1%
