Question

element A has two isotopes. The first isotope is pressnt 18.48% of the time and has a mass of 135.24. The second isotope has a mass of 116.1. calculate the atomic mass of element A

Answer 1

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Answer 2

To calculate the atomic mass of element A, we need to consider the masses and relative abundances of its isotopes.

Let's assume the first isotope has a mass of x and is present 18.48% of the time. The second isotope has a mass of 116.1 and is present (100 - 18.48)% = 81.52% of the time.

We can set up the following equation based on the weighted average:

(x * 18.48%) + (116.1 * 81.52%) = Atomic mass of element A

Simplifying the equation:

0.1848x + 95.02672 = Atomic mass of element A

To solve for x, we subtract 95.02672 from both sides:

0.1848x = Atomic mass of element A - 95.02672

Now, we substitute the mass value of the first isotope (135.24) for x:

0.1848(135.24) = Atomic mass of element A - 95.02672

24.99152 = Atomic mass of element A - 95.02672

To find the atomic mass of element A, we add 95.02672 to both sides:

Atomic mass of element A = 24.99152 + 95.02672

Atomic mass of element A = 120.01824

Therefore, the atomic mass of element A is approximately 120.018 (to 3 decimal places).