Question

Hypothetical element X has 3 stable isotopes. The relative peak intensities are 79.52 for 180.0 u, 100.0 for 184.0 u, and 82.98 for 186.0 u. What is the average atomic mass for X

Answer 1

Answer:

The relative atomic mass of X is 183.4

Explanation:

The relative atomic mass of an element is the weighted average of the masses of the isotopes using the carbon-12 atom has a mass of exactly 12 units as as a standard.

The relative sizes of the peaks gives a direct measure of the relative abundances of the isotopes. The tallest peak is often given an arbitrary height of 100 and is known as the base peak.

To calculate the relative atomic mass of the element X which has 3 stable isotopes with the relative peak intensities as given below:

79.52 for 180.0 u, 100.0 for 184.0 u, and 82.98 for 186.0 u, the sum of the products of the relative peak intensity of each isotope and their isotopic mass is divided by the sum of the peak intensities.

Relative atomic mass of X = (79.52 × 180) + (100 × 184.0) + (82.98 × 186)/(79.52 + 100 + 82.98)

Relative atomic mass of X = (14313.6 + 18400 + 15434.28)/(262.5)

Relative atomic mass of X = 48147.88/262.5 = 183.4

Therefore, the relative atomic mass of X is 183.4