Which statement best explains the purpose of using a mole in the measurement of matter?

• A. It allows chemists to count atoms, molecules, or ions by relating their mass to a fixed number of particles.
• B. It is a unit for measuring the concentration of solutions.
• C. It is used to measure the volume of gases at standard temperature and pressure.
• D. It provides a way to compare the densities of different substances.

Answer: (A)

Verified step by step guidance

1. Understand that the mole is a fundamental unit in chemistry used to count very small particles like atoms, molecules, or ions, which are too tiny to count individually.
2. Recognize that one mole corresponds to a fixed number of particles, specifically Avogadro's number, which is \$6.022 \times 10^{23}$ particles.
3. Know that the mole links the microscopic scale (individual particles) to the macroscopic scale (measurable amounts of substance) by relating the mass of a substance to a specific number of particles.
4. Realize that this relationship allows chemists to convert between the mass of a substance and the number of particles it contains, facilitating calculations in chemical reactions and measurements.
5. Therefore, the mole's purpose is to provide a bridge between mass and number of particles, enabling chemists to count atoms, molecules, or ions indirectly by measuring mass.