Amount of Substance
Convert between mass, moles, gas volume at STP and number of particles: n = m/M, n = V/Vm, n = N/NA, with a solution.
The number of particles can be written in scientific notation: 3.01e23. Write formulas in Latin letters starting with a capital: H2SO4, Ca(OH)2, CuSO4·5H2O (water of crystallization after a dot or *).
The amount of substance calculator takes one known quantity — mass, amount (moles), gas volume or number of particles — and finds all the others. The solution shows the molar mass and the conversion formulas.
Formulas
| Known | Amount of substance |
|---|---|
| mass m | n = m / M |
| gas volume V (STP) | n = V / Vm, Vm = 22.4 L/mol |
| number of particles N | n = N / NA, NA = 6.02 · 1023 mol−1 |
The inverse formulas are m = n · M, V = n · Vm, N = n · NA. The volume at standard conditions (0 °C, 101.3 kPa) is calculated only for gases.
Example 1. 36 g of water: n = 36 / 18 = 2 mol, N = 2 · 6.02 · 1023 = 1.204 · 1024 molecules.
Example 2. 5.6 L of CO2: n = 5.6 / 22.4 = 0.25 mol, m = 0.25 · 44 = 11 g.
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