Calculating Average Atomic Mass ~ Review 2024

Front

What is average atomic mass?

Back

The weighted average of the masses of an element's isotopes, taking into account their relative abundances.

Front

How do you calculate average atomic mass?

Back

Multiply the mass of each isotope by its relative abundance (as a decimal), then sum these values.

Front

What is the formula for calculating average atomic mass?

Back

Average Atomic Mass = (mass1 * abundance1) + (mass2 * abundance2) + ... + (massN * abundanceN)

Front

What is an isotope?

Back

Atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different masses.

Front

What is relative abundance?

Back

The percentage of a specific isotope of an element compared to the total amount of that element's isotopes.

Front

If an element has two isotopes with masses of 10 amu and 12 amu, and their abundances are 75% and 25%, what is the average atomic mass?

Back

Average Atomic Mass = (10 amu * 0.75) + (12 amu * 0.25) = 10.5 amu.

Front

What is the average atomic mass of an element with isotopes of 20 amu (50% abundance) and 22 amu (50% abundance)?

Back

Average Atomic Mass = (20 amu * 0.50) + (22 amu * 0.50) = 21 amu.

Front

What is the significance of the atomic mass listed on the periodic table?

Back

It represents the weighted average of all naturally occurring isotopes of an element.

Front

How does the abundance of isotopes affect the average atomic mass?

Back

Higher abundance of a heavier isotope increases the average atomic mass, while higher abundance of a lighter isotope decreases it.

Front

What is the average atomic mass of an element with isotopes of 30 amu (10% abundance), 31 amu (20% abundance), and 32 amu (70% abundance)?

Back

Average Atomic Mass = (30 amu * 0.10) + (31 amu * 0.20) + (32 amu * 0.70) = 31.4 amu.