Library / Foundations: Chemistry / FCH-04
Foundations: Chemistry
Number of particles (Avogadro)
Count atoms, molecules or ions from the number of moles.
- Ref
- FCH-04
- Rev
- v1
- Field
- Foundations: Chemistry
- Result
- N [10²³]
N is the number of particles, n the amount in mol and NA = 6.022 × 10²³ mol⁻¹ is the Avogadro constant.
One mole always contains the same enormous number of particles, whatever the substance.
Calculator
10²³
mol
- Number of particles per mmol6.022 10²⁰
- Mass of one particle (if M = 18)2.989 10⁻²³ g
What drives the result
Each variable is moved across its typical range while the others stay at the values above. The longest bar is the key driver.
Number of particles (10²³) current value 3.011 10²³
nAmountKey driver
6.02e-6602
- Half a mole of anything contains about 3 × 10²³ particles.
- Solids, liquids and gases at the same number of moles all contain the same number of particles.
Chart data as tables
Ranked variables
| Variable | Typical range | Lowest result | Highest result | Swing (10²³) | Local step | Change in result |
|---|---|---|---|---|---|---|
| n Amount | 1e-6 to 100 mol | 6.022e-6 | 602.2 | 602.2 | +10% | +10 % |
Sweep of Amount
| Amount (mol) | Number of particles (10²³) |
|---|---|
| 1e-6 | 6.022e-6 |
| 1e-5 | 6.022e-5 |
| 1e-4 | 6.022e-4 |
| 0.001 | 0.006022 |
| 0.01 | 0.06022 |
| 0.1 | 0.6022 |
| 1 | 6.022 |
| 10 | 60.22 |
| 100 | 602.2 |
Sweep one variable
Number of particles (10²³)Hover, touch, or use the arrow keys on the chart
Variables and how each one contributes
N
Number of particles
What the equation gives you. Everything else feeds it.
n
Amount
Amount of substance. Directly proportional.
Worked example with the values above
- NA = 6.022 × 10²³ per mole.
- N = 0.5 × 6.022×10²³.
- N = 3.011 × 10²³ particles.
Assumptions and limits
- Countable particles of one type.
- Do not mix atoms with molecules (O₂ has two atoms per particle).
Common mistakes
- Forgetting the number of atoms in each molecule.
- Dropping the power of ten.
Statistics and uncertainty
NA is now fixed exactly by definition, so any uncertainty comes from the measured moles.
Where it is used
- Estimating atoms in a sample.
- Scaling between macroscopic and atomic scales.
Maths you need
- Powers of ten: standard form
- The mole: counting unit