Atomic Mass and Calculations

The video tutorial explains the concept of atomic mass and the challenges of dealing with very small numbers. It introduces the atomic mass unit (AMU) as a convenient measure for atomic mass. The tutorial covers isotopes and the average atomic mass, using examples to illustrate calculations. It concludes with an exercise on calculating the mass of aluminum atoms, emphasizing the practical application of these concepts.

Why did scientists create the atomic mass unit (amu)?

• To replace the metric system

• To simplify calculations with very small atomic masses

• To measure distances between cities

• To standardize the length of a foot

What does the abbreviation 'amu' stand for?

• Atom Mass Universal

• Atomic Mass Utility

• Atomic Mass Unit

• Atomic Measurement Unit

How is the average atomic mass of an element determined?

• By measuring the mass of a single atom

• By averaging the masses of all isotopes of the element

• By counting the number of protons in the atom

• By using the metric system

How is the concept of average atomic mass similar to weighing a bag of jelly beans?

• Both are unrelated concepts

• Both are measured in kilograms

• Both require counting the exact number of items

• Both involve calculating the average mass of individual items

What is the average atomic mass of carbon as found on the periodic table?

• 12.01 amu

• 14.01 amu

• 10.01 amu

• 16.01 amu

If the average mass of one carbon atom is 12.01 amu, what is the mass of 431 carbon atoms?

• 5178.31 amu

• 5178.31 kilograms

• 5178.31 milligrams

• 5178.31 grams

What is the atomic mass of aluminum as given in the exercise?

• 24.98 amu

• 25.98 amu

• 27.98 amu

• 26.98 amu

How do you calculate the mass of 75 atoms of aluminum?

• Multiply the number of atoms by the atomic mass

• Divide the atomic mass by the number of atoms

• Subtract the number of atoms from the atomic mass

• Add the atomic mass to the number of atoms

What is the significance of significant figures in the calculation of atomic masses?

• They help in rounding off the final result

• They are irrelevant in atomic calculations

• They are used to measure distances

• They determine the number of atoms

What is the rounded mass of 75 aluminum atoms considering significant figures?

• 2024 amu

• 2023 amu

• 2025 amu

• 2022 amu