|Question 27Verbal

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While researching a topic, a student has taken the following notes:
- The ratio of the total mass of an element to the combined mass of all elements in a given environment is called the mass fraction.
- The mass fraction of chromium (Cr) on Earth is 4,700 parts per million (ppm).
- This indicates that the relative abundance of chromium on Earth is 0.47%.
- The ratio of the total number of atoms of an element to the total number of all atoms in a given environment is called the mole fraction.
- The mole fraction of chromium on Earth is 2,300,000 parts per billion (ppb).
- This indicates that the relative abundance of chromium on Earth is 0.23%.
The student wants to emphasize a similarity between mass fraction and mole fraction. Which choice most effectively uses relevant information from the notes to accomplish this goal?
On Earth, the mass fraction of chromium is 4,700 ppm, or 0.47%, and the mole fraction is 2,300,000 ppb, or 0.23%.
A
While mass fraction is a measure of relative mass and mole fraction is a measure of relative atom count, both indicate the relative abundance of elements on Earth.
B
Both mass and mole fraction express the relative abundance of chromium on Earth as a ratio of the total mass of chromium to the combined mass of all atoms.
C
The mass fraction of chromium indicates its relative mass; in addition, the element's mole fraction indicates the relative number of chromium atoms.
D