Calculating Atomic Mass: Practice Problems and Solutions

The video tutorial explains the concept of isotopes and how to calculate the average atomic mass using Gallium, Rubidium, and Magnesium as examples. It covers the meaning of 'respectively' in the context of isotopes, demonstrates the calculation process for Gallium's average atomic mass, discusses the abundance of Rubidium isotopes, and calculates the average atomic mass for Magnesium isotopes.

What does the term 'respectively' mean in the context of isotope masses?

• The first mass corresponds to the first isotope mentioned, and the second mass to the second isotope.

• The masses are listed in reverse order.

• The masses are not related to the isotopes mentioned.

• The masses are averaged together.

What is the mass of Gallium 69?

• 68.926 amu

• 60.11 amu

• 69.72 amu

• 70.925 amu

How do you express the percent abundance of Gallium 69 as a decimal?

• 0.6011

• 60.11

• 0.3989

• 39.89

What is the average atomic mass of Gallium?

• 68.926 amu

• 70.925 amu

• 69.72 amu

• 60.11 amu

Which isotope of Rubidium is more abundant based on its atomic weight?

• Rubidium 85

• Rubidium 87

• Cannot be determined

• Both are equally abundant

What is the atomic mass of Rubidium 85?

• 86.909 amu

• 85.47 amu

• 84.911 amu

• 87.000 amu

Why is the atomic weight of Rubidium closer to 85.47 amu?

• Because the atomic weight is an average of 85 and 87

• Because Rubidium 85 is more abundant

• Because Rubidium 87 is more abundant

• Because both isotopes are equally abundant

What is the mass of Magnesium 24?

• 24.9586 amu

• 25.983 amu

• 24.31 amu

• 23.985 amu

How do you express the percent abundance of Magnesium 24 as a decimal?

• 0.7899

• 0.110

• 0.6011

• 0.1000

What is the average atomic mass of Magnesium?

• 23.985 amu

• 24.31 amu

• 24.9586 amu

• 25.983 amu