Question

An unknown element, X, is isolated and examined. It is determined that 91.0% of the sample is composed of the isotope 75X while the other 9.00% of the sample is composed of 77X. Based on this information, what is the atomic mass of element X?

Answer 1

Natural abundance of X is 75.18amu.

Step-by-step explanation:

The atomic mass of an element is defined as the mass of its isotopes times its natural abundance.

In the unknown element X, the atomic mass of the isotope ⁷⁵X is 75 amu and of ⁷⁷X is 77 amu.

That means the natural abundance of X is:

75amu*91.0% + 77amu*9.00%

Natural abundance of X is 75.18amu