Final answer:
To calculate the percentage abundance of each isotope and the isotopic ratio, use the provided information and apply the weighted average formula. The percentage abundance of the first isotope is found to be 60% and the second isotope is 40%. The isotopic ratio is 3/2 or 1.5.
Step-by-step explanation:
In order to calculate the percentage abundance of each isotope and the isotopic ratio, we need to use the provided information. The atomic mass of the element is 69.72AMU, with isotopes of mass 68.925AMU and 70.9245AMU. Let's denote the percentage abundance of the first isotope as x. Since the total abundance of isotopes is 100%, the abundance of the second isotope would be (100 - x)%.
The atomic mass can be calculated using the weighted average formula:
(mass of isotope 1 * abundance of isotope 1 + mass of isotope 2 * abundance of isotope 2) / 100 = atomic mass
Substituting the given values, we have:
((68.925 * x) + (70.9245 * (100 - x))) / 100 = 69.72
Simplifying the equation, we get:
68.925x + 7092.45 - 70.9245x = 6972
-1.9995x = -120.45
x = 60
Therefore, the percentage abundance of the first isotope is 60%, and the percentage abundance of the second isotope is 40%.
The isotopic ratio can be calculated by dividing the percentage abundance of the two isotopes. In this case, the isotopic ratio is 60/40, which simplifies to 3/2 or 1.5.