Question

A hypothetical element consists of two isotopes of masses 86.95 amu and 88.95 amu with abundances of 35.5% and 64.5%, respectively. What is the average atomic mass of this element? A.) 87.95 amu B.) 87.7 amu C.) 88.2 amu D.) 86.95 amu

Answer 1

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

Answer 2

The average atomic mass of the hypothetical element with two isotopes of masses 86.95 amu (35.5% abundance) and 88.95 amu (64.5% abundance) is calculated by multiplying each isotope's mass by its respective decimal abundance and summing the results, yielding 88.2 amu.

Step-by-step explanation:

To calculate the average atomic mass of a hypothetical element that has two isotopes, we need to take into account the masses and the relative abundances of each isotope.

The first isotope has a mass of 86.95 amu and an abundance of 35.5%. The second isotope has a mass of 88.95 amu and an abundance of 64.5%. To find the average atomic mass, we multiply the mass of each isotope by its decimal abundance and then sum the values:

(86.95 amu × 0.355) = 30.86725 amu

(88.95 amu × 0.645) = 57.37275 amu

Adding these two results gives the average atomic mass of the element:

30.86725 amu + 57.37275 amu = 88.240 amu

Therefore, the average atomic mass of the element is 88.24 amu, which corresponds to option C 88.2 amu.