Isotopic Abundance Calculation in Rubidium Isotopes

The video tutorial explains how to determine the isotopic abundance of Rubidium's isotopes, RB85 and RB87. It begins by introducing the concept of isotopic abundance and setting up the problem using a chart. The tutorial then formulates an equation for the average atomic mass based on the isotopic masses and their respective abundances. The instructor demonstrates solving the linear equation to find the abundance percentages of each isotope. The video concludes with a summary of the process and additional tips for solving similar problems.

What are the masses of the isotopes RB85 and RB87?

• 84.9117 and 86.9085

• 85.4678 and 86.9085

• 85.4678 and 87.9085

• 84.9117 and 85.4678

What is the total percentage that isotopic abundances must add up to?

• 75%

• 100%

• 25%

• 50%

If RB85 has an isotopic abundance of X, what is the abundance of RB87?

• X

• 100% + X

• 100% - X

• X - 100%

What is the purpose of setting up an average atomic mass equation?

• To calculate the total number of isotopes

• To measure the atomic radius

• To determine the isotopic abundances

• To find the mass of a single isotope

What is the average atomic mass given in the problem?

• 84.9117

• 85.4678

• 86.9085

• 87.4678

How do you solve for X in the linear equation?

• Subtract X from both sides

• Divide by the coefficient of X

• Add X to both sides

• Multiply both sides by X

What is the isotopic abundance of RB85 after solving the equation?

• 100%

• 27.85%

• 72.15%

• 50%

What is the isotopic abundance of RB87?

• 50%

• 27.85%

• 72.15%

• 100%

What is the method used to solve for missing isotopic abundances?

• Using a calculator

• Setting up a chart and solving algebraically

• Guessing the values

• Using a periodic table

What is the final step in converting the decimal abundance to a percentage?

• Divide by 100

• Multiply by 10

• Multiply by 100

• Divide by 10