Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

Which of the following statements about moles is true?

1. One mole of any substance contains the same number of particles

2. One mole only applies to gases

3. Moles measure volume, not mass

4. Moles are only relevant for chemical reactions

The correct answer is: One mole of any substance contains the same number of particles

The statement that one mole of any substance contains the same number of particles is accurate because it reflects Avogadro's constant, which states that one mole of any substance contains approximately \( 6.022 \times 10^{23} \) entities, whether they are atoms, molecules, ions, or any other defined particle. This principle is fundamental in chemistry, as it allows for the comparison of amounts of different substances in relation to their particles and serves as a bridge between the macroscopic scale of substances we can measure and the microscopic scale of atoms and molecules. The other options do not hold true in the context of chemistry. For instance, the idea that one mole only applies to gases is incorrect because moles can be used to quantify solids, liquids, and gases alike. Similarly, leveraging moles to measure volume rather than mass is not accurate, as they are a unit of measurement based on the number of particles rather than their volumetric or mass properties. Finally, the assertion that moles are only relevant for chemical reactions overlooks their broad application in stoichiometry, solution concentrations, and various practical calculations in both physical and analytical chemistry.