Overview
This lecture explains how to convert between moles and numbers of atoms or molecules using both common sense and conversion factors.
Moles to Atoms Conversion
- Atoms and molecules can both be referred to as "particles."
- One mole equals 6.02 x 10^23 particles (Avogadro's number).
- To find atoms in 5.5 moles: multiply 5.5 by 6.02 x 10^23.
- Enter 5.5 * (6.02E23) in a scientific calculator for the answer.
- Result: 3.3 x 10^24 atoms, rounded to two significant figures.*
Using Conversion Factors (Moles ↔ Atoms)
- Conversion factors allow unit cancellation to move between moles and atoms.
- Write as (1 mole / 6.02 x 10^23 atoms) or (6.02 x 10^23 atoms / 1 mole).
- Multiply by the conversion factor with "moles" in the denominator to cancel units and leave "atoms."
Atoms to Moles Conversion
- To convert number of atoms to moles, divide by 6.02 x 10^23.
- Example: 4.6 x 10^24 sulfur atoms ÷ 6.02 x 10^23 = 7.6 moles (rounded to two significant figures).
- Enter (4.6E24) / (6.02E23) in a scientific calculator for the answer.
- When using conversion factors, choose the version with "atoms" on the denominator to cancel units.
Key Terms & Definitions
- Mole — A quantity equal to 6.02 x 10^23 particles (Avogadro's number).
- Avogadro's number — 6.02 x 10^23, the number of particles in one mole.
- Particle — Any individual thing (atom, molecule, etc.).
- Conversion Factor — A fraction that represents the relationship between two units and is used to convert from one unit to another.
Action Items / Next Steps
- Practice more conversion problems with the next video: "Converting between Moles, Atoms, and Molecules part 2."