Calculating Average Atomic Mass of Isotopes

This video tutorial introduces the concept of average atomic mass, explaining it as a weighted average similar to how grades are calculated. The instructor uses nitrogen isotopes as an example to demonstrate the calculation process, emphasizing the importance of relative abundance. The video also covers the use of a mass spectrometer to identify unknown elements, providing a detailed example problem to illustrate the process. The tutorial concludes with a call to action for viewers to engage with the content.

What is average atomic mass compared to in the introduction?

• Daily grades

• Test grades

• Class participation

• Weighted averages used in grading

What does relative abundance refer to?

• The total mass of an element

• The percentage of each isotope in a sample

• The number of protons in an isotope

• The number of neutrons in an isotope

Which isotope of nitrogen is most abundant on Earth?

• Nitrogen-15

• Nitrogen-17

• Nitrogen-14

• Nitrogen-16

What is the first step in calculating average atomic mass?

• Adding the mass numbers

• Dividing the mass numbers by their relative abundance

• Multiplying mass numbers by their relative abundance

• Subtracting the mass numbers

What is the average atomic mass of nitrogen based on the given example?

• 14.07

• 17.07

• 15.07

• 16.07

What does a mass spectrometer measure?

• The temperature of an element

• The mass and relative abundance of isotopes

• The density of an element

• The volume of an element

What is the relative abundance of the isotope with a mass number of 90 in the example?

• 50%

• 18%

• 4%

• 10%

What is the mass number of the isotope with a 4% relative abundance in the example?

• 91

• 90

• 94

• 96

What is the calculated average atomic mass of the unknown element in the example?

• 93.42

• 92.42

• 91.42

• 90.42

Which element was identified using the mass spectrometer in the example?

• Carbon

• Zirconium

• Oxygen

• Nitrogen