To determine the atomic mass of an element MCl3, where the mass of chlorine accounts for 67.2%, we need to consider the relative contributions of the different isotopes of chlorine. Chlorine has two stable isotopes: chlorine-35 and chlorine-37, with natural abundances of approximately 75.53% and 24.47%, respectively.
Let's assume that the element M has a single stable isotope, M-x, with a natural abundance of 100%.
The atomic mass of MCl3 can be calculated as follows:
(0.6753 * (mass of M-x)) + (0.247 * 35.453 u) + (0.0753 * 37.453 u) = atomic mass of MCl3
Here, 35.453 u and 37.453 u represent the atomic masses of chlorine-35 and chlorine-37, respectively.
To solve for the atomic mass of MCl3, we need to know the atomic mass of M-x. However, without additional information about the specific element M, we cannot determine its atomic mass or calculate the atomic mass of MCl3.