Molar Relationships

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Mole Noun

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[mohl]

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Mole

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The SI unit for the amount of a substance, defined as containing exactly 6.022 x 10^23 representative particles.

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Example: This image shows that one mole is a specific quantity (6.022 x 10^23 particles) and has a specific mass, like 12 grams of carbon-12.

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Representative Particles Noun

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[rep-ri-zen-tuh-tiv par-ti-kuhls]

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Representative Particles

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The smallest individual units of a substance, which can be atoms, molecules, or formula units depending on the substance.

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Example: This diagram shows that one mole of a substance is equal to 6.02 x 10^23 representative particles, such as atoms or molecules.

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Avogadro's Number Noun

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[ah-vuh-gah-drohz num-ber]

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Avogadro's Number

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The number of representative particles in one mole of a substance, which is approximately 6.022 x 10^23 particles per mole.

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Example: The image shows that Avogadro's number (6.02 x 10^23) of carbon atoms has a mass of 12 grams, visually connecting the count of atoms to their measurable mass.

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Molar Mass Noun

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[moh-ler mas]

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Molar Mass

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The mass in grams of one mole of a substance, used as a conversion factor between the mass and moles.

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Example: This image shows a cartoon mole (representing the unit "mole") on a weighing scale, visually defining Molar Mass as the mass of one mole.

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Formula Unit Noun

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[for-myoo-luh yoo-nit]

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Formula Unit

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The simplest whole-number ratio of ions in an ionic compound, serving as its representative particle for stoichiometric calculations.

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Example: This image shows the crystal lattice of sodium chloride (NaCl), where positive sodium ions (Na+) and negative chloride ions (Cl-) repeat in a 1:1 ratio.

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Avogadro's Hypothesis Noun

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[ah-vuh-gah-drohz hy-poth-uh-sis]

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Avogadro's Hypothesis

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A principle stating that equal volumes of all gases at the same temperature and pressure contain an equal number of particles.

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Example: This image shows that as you add more gas particles (moles) to a container, the space they take up (volume) increases, assuming constant conditions.

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Molar Volume Noun

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[moh-ler vol-yoom]

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Molar Volume

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The volume occupied by one mole of any ideal gas at standard temperature and pressure, which is approximately 22.4 liters.

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Example: This formula triangle shows the relationship between the volume of a gas, its amount in moles, and the molar volume constant (24 dm³/mol).

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Density Noun

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[den-si-tee]

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Density

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An intensive physical property of a substance, defined as the ratio of its mass to its volume (mass per unit volume).

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Example: This image shows two cubes of the same size on a balance. The cube with more particles (more mass) is heavier, demonstrating it has a higher density.

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Atom Noun

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[at-uhm]

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Atom

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The smallest unit of an element that maintains the chemical identity of that element; a type of representative particle.

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Example: An atom consists of a central nucleus containing positively charged protons and neutral neutrons, with negatively charged electrons orbiting the nucleus.

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Molecule Noun

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[mol-i-kyool]

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Molecule

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A neutral group of two or more atoms held together by covalent chemical bonds; a type of representative particle.

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Example: This image shows that a molecule, like water (H₂O), is a single particle made of two or more atoms (two hydrogen and one oxygen) bonded together.