What is the average mass of the mixture of an element's isotopes?

To calculate the average mass of the mixture of an element's isotopes, you need to consider the abundance of each isotope. Here's how you can do it:

1. Find the atomic mass of each isotope: The atomic mass of an isotope is usually given in atomic mass units (amu) and can be found on the periodic table or in other reference materials.

2. Determine the abundance of each isotope: The abundance of an isotope is expressed as a percentage or decimal fraction that represents the proportion of that isotope in a natural sample of the element. This information is also commonly found on the periodic table or in reference books.

3. Multiply the atomic mass of each isotope by its abundance: Multiply each isotope's atomic mass by its abundance percentage or decimal fraction. This will give you the contribution of each isotope to the overall average mass.

4. Sum up the contributions: Add up the products obtained in step 3 to calculate the total contribution of all the isotopes.

Here's an example:

Let's consider the element carbon (symbol: C) as an example. Carbon has two naturally occurring isotopes, carbon-12 (12C) and carbon-13 (13C). The atomic mass of carbon-12 is 12.000 amu, and the atomic mass of carbon-13 is 13.003 amu. The abundance of carbon-12 is about 98.9%, and the abundance of carbon-13 is about 1.1%.

To calculate the average mass of carbon's isotopes:

(12.000 amu × 0.989) + (13.003 amu × 0.011) = Average mass of carbon

This calculation will give you the average mass of a mixture of carbon's isotopes. In this case, it calculates to be approximately 12.01 amu.

Keep in mind that the exact values for atomic masses and isotope abundances may vary slightly depending on the source and the element in question.