Question

PLEASE HELP ASAP

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An isotope of element X has a mass of 12.32 amu and a relative abundance of 19.5%; a second isotope has a mass of 13.08 amu and a relative abundance of 26.23%; the third isotope in the sample has a mass of 11.99 amu and a relative abundance of 54.27%. Calculate the atomic mass of element X

Answer 1

12.34 amu

Step-by-step explanation:

Let the 1st isotope be A

Let the 2nd isotope be B

Let the 3rd isotope be C

From the question given above, the following data were obtained:

1st Isotope (A):

Mass of A = 12.32 amu

Abundance (A%) = 19.5%

2nd isotope (B):

Mass of B = 13.08 amu

Abundance (B%) = 26.23%

3rd isotope (C):

Mass of C = 11.99 amu

Abundance (C%) = 54.27%

Atomic mass of X =?

The atomic mass of the element X can be obtained as follow:

Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]

= [(12.32 × 19.5)/100] + [(13.08 × 26.23)/100] + [(11.99 × 54.27)/100]

= 2.402 + 3.431 + 6.507

= 12.34 amu

Thus, the atomic mass of the element X is 12.34 amu