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

What is the significance of the number 6.022 x 10^23 in chemistry?

1. It represents the number of grams in a mole

2. It is Avogadro's number, representing the number of particles in a mole

3. It is the mass of one mole of carbon

4. It indicates the density of water

The correct answer is: It is Avogadro's number, representing the number of particles in a mole

The number 6.022 x 10^23 is known as Avogadro's number, and it is a fundamental constant in chemistry. This number signifies the quantity of particles, whether those are atoms, molecules, or ions, that are contained in one mole of a substance. The mole is a standard unit of measurement in chemistry, allowing chemists to count quantities of very small entities by weighing macro quantities of material. For example, when you have one mole of carbon atoms, it contains exactly 6.022 x 10^23 carbon atoms. This concept is integral to the field of chemistry because it links the atomic scale to the macroscopic scale, making it possible to perform calculations involving the amounts of substances in reactions, their relationships, and their properties. Understanding Avogadro's number is essential for stoichiometry, which is the calculation of reactants and products in chemical reactions. Other choices do not accurately describe the significance of this number. While one mole of any substance does have a specific mass in grams (which is the molar mass), this mass varies depending on the substance and is not represented solely by Avogadro's number. The mass of one mole of carbon is indeed 12 grams, but this is