Avogadro's Number and Atomic Mass Units (Video Notes)

Vocabulary flashcards covering amu, Avogadro's number, gram-to-amu conversions, and the mass-counting analogy from the lecture notes.

Avogadro's number (NA)

6.02214 × 10^23 particles per mole; the conversion factor between grams and atomic mass units (1 g contains 6.02214 × 10^23 amu).

Atomic mass unit (amu)

Exactly 1/12 the mass of a carbon-12 atom; equals 1.66054 × 10^-24 g.

Carbon-12 isotope

Reference isotope used to define the amu; its mass is defined as 12 amu.

Gram-to-amu conversion

Since 1 amu = 1.66054 × 10^-24 g, 1 g = 6.02214 × 10^23 amu (the Avogadro number expressed as a mass conversion).

Mass-based counting (balance method)

If the mass of a single atom is known, the number of atoms in a sample can be found by dividing the total mass by the single-atom mass.

Macroscopic–nanoscopic bridge

Avogadro's number connects macroscopic measurements (mass of a sample) to the nanoscopic world (number of atoms) by converting grams to numbers of atoms.

Analogy: counting yellow spheres

Weigh a large container of tiny spheres; the count equals the total mass divided by the mass of one sphere, illustrating how atom counts are obtained.