Average Atomic Mass

What is the formula to calculate average atomic mass?

• Sum of (mass of isotope * relative abundance)

• Sum of (mass of each isotope * relative abundance) / total number of isotopes

• Sum of (relative abundance / total number of isotopes)

• Sum of (mass of each isotope / total number of isotopes)

How is the average atomic mass of an element calculated?

• Sum of the masses of all naturally occurring isotopes.

• Average of the masses of all naturally occurring isotopes.

• Weighted average of the masses of all artificially created isotopes.

• Weighted average of the masses of all naturally occurring isotopes

Why is the average atomic mass of an element usually not a whole number?

• Different isotopes of the element have different masses and their abundance affects the average atomic mass.

• The average atomic mass is always a whole number.

• The average atomic mass is rounded to the nearest whole number.

• The atomic mass of an element is determined by its atomic number.

What are isotopes?

• Atoms of different elements that have the same number of neutrons.

• Atoms of different elements that have the same number of protons.

• Atoms of the same element that have different numbers of protons.

• Atoms of the same element that have different numbers of neutrons.

Tags

NGSS.HS-PS1-8

How do you calculate the average atomic mass of an element with isotopes?

• Add the mass of each isotope by its relative abundance and sum up the results.

• Divide the mass of each isotope by its relative abundance and sum up the results.

• Multiply the mass of each isotope by its relative abundance and sum up the results.

• Subtract the mass of each isotope by its relative abundance and sum up the results.

What is the unit for average atomic mass?

• grams

• seconds

• amu

• meters

Why is it important to know the average atomic mass of an element?

• To determine the isotopic composition and calculate the amount of each isotope present in a sample.

• To determine the melting point of the element.

• To determine the boiling point of the element.

• To calculate the number of valence electrons in the element.

Tags

NGSS.HS-PS1-7

What is the difference between mass number and average atomic mass?

• Atomic mass is the mass of an atom's nucleus, while average atomic mass is the mass of an atom's protons and neutrons.

• Atomic mass is the mass of an atom's nucleus, while average atomic mass is the mass of an atom's electron cloud.

• Atomic mass is the mass of an atom's protons and neutrons, while average atomic mass is the mass of an atom's electrons.

• Atomic mass is the mass of a single atom, while average atomic mass is the weighted average of all the isotopes' masses.

What is the average atomic mass of carbon?

• 15.25 amu

• 10.05 amu

• 12.01 amu

• 13.99 amu

If an element has two isotopes with masses of 10 amu and 12 amu, and their abundances are 25% and 75% respectively, what is the average atomic mass of the element?

• 13 amu

• 9.5 amu

• 11.5 amu

• 10.5 amu