Understanding Relative Atomic Mass

This video tutorial explains how to calculate the relative atomic mass of an element using its isotopic abundances. It begins with an example of carbon, where the relative atomic mass is close to 12 due to the high abundance of carbon-12 isotopes. The tutorial then explores chlorine, which has two isotopes, chlorine-35 and chlorine-37, and demonstrates how to calculate its relative atomic mass by multiplying the isotopic mass numbers by their respective abundances and summing the results. A challenge is presented to calculate the relative atomic mass of uranium, reinforcing the method. The video concludes with a summary of the steps involved in calculating relative atomic mass.

What is the relative atomic mass of carbon based on its isotopic abundance?

• Approximately 14 atomic mass units

• Approximately 12 atomic mass units

• Approximately 16 atomic mass units

• Approximately 10 atomic mass units

How many protons are present in both chlorine isotopes?

• 18 protons

• 16 protons

• 17 protons

• 19 protons

What is the number of neutrons in the chlorine-37 isotope?

• 20 neutrons

• 19 neutrons

• 21 neutrons

• 18 neutrons

What percentage of chlorine atoms in nature are chlorine-35 isotopes?

• 75%

• 50%

• 100%

• 25%

To calculate the relative atomic mass of chlorine, what should you do with the isotopic abundances?

• Divide them by the mass number

• Multiply them by the mass number and add the products

• Add them together

• Subtract them from the mass number

What is the final step in calculating the relative atomic mass of chlorine?

• Add 100

• Multiply by 100

• Divide by 100

• Subtract 100

What is the relative atomic mass of chlorine after calculation?

• 36.5

• 33.5

• 34.5

• 35.5

What is the first step in calculating the relative atomic mass of uranium?

• Multiply the relative abundances by the mass number

• Subtract the mass numbers

• Divide the mass numbers

• Add the mass numbers

What is the relative atomic mass of uranium after calculation?

• 237.99

• 236.99

• 238.99

• 239.99

What is the general process to calculate the relative atomic mass of an element?

• Multiply the relative abundances by the mass number, add the products, and divide by 100

• Add the isotopic masses

• Multiply the isotopic masses

• Subtract the isotopic masses