Final answer:
To calculate the average atomic mass of a hypothetical element with isotope masses of 86.95 amu and 88.95 amu at abundances of 35.5% and 64.5%, respectively, multiply each mass by its decimal abundance and sum the results. The calculation yields an average atomic mass of 88.22 amu, so the correct answer is C) 88.2 amu.
Step-by-step explanation:
The average atomic mass of an element with isotopes can be calculated using the isotopes masses and their relative abundances. To find the average atomic mass of the hypothetical element with isotopes of masses 86.95 amu and 88.95 amu, and abundances of 35.5% and 64.5%, respectively, you would do the following calculation:
Convert the percentage abundances to decimals by dividing by 100.
Multiply each isotope's mass by its decimal abundance.
Sum the products to find the average atomic mass.
The calculation would look like this:
(86.95 amu × 0.355) + (88.95 amu × 0.645) = 30.87725 amu + 57.37275 amu = 88.25 amu
However, the correct calculation based on the student's provided data would be:
(86.95 amu × 0.355) + (88.95 amu × 0.645) = 30.84725 amu + 57.37275 amu = 88.22 amu
Answer: C) 88.2 amu