Moles to Equivalents Converter
Common Conversions
| mol | eq |
|---|---|
| 0.01 | 0.01 |
| 0.1 | 0.1 |
| 0.5 | 0.5 |
| 1 | 1 |
| 2 | 2 |
| 5 | 5 |
| 10 | 10 |
| 0.5 | 1 |
| 1 | 2 |
| 1 | 3 |
| 1 | 5 |
Why this conversion matters in chemistry
Acid-base titration math runs on equivalents rather than moles because what the titrant consumes is one proton (or electron) per reactive site. 0.050 mol of H₂SO₄ gives 0.100 equivalents of acid — the base needed to reach the second endpoint. 0.050 mol of Na₂CO₃ gives 0.100 equivalents for full neutralization to CO₂. The mole-equivalent step normalizes different polyprotic acids, polyatomic bases, and multi-electron oxidants onto a common titration scale. The valence factor n is reaction-specific, not intrinsic to the substance.
Formula
Where the factor comes from
Start from the reaction, because nothing else here fixes anything. The value of n is the number of reacting units each formula unit contributes — protons in an acid-base step, electrons in a redox half-reaction, charge number for a simple ion in a charge-balance ledger — and eq = mol × n follows directly from that. The multiplication is trivial; sourcing n is the whole job. For a strong monoprotic acid n is 1 and the two numbers coincide, which is why the distinction stays invisible until the first polyprotic or multi-electron case arrives. Note the asymmetry with the reverse direction as well: recovering moles from equivalents needs the same n, so a value recorded only in equivalents is not fully recoverable unless the reaction was recorded beside it.
Precision and significant figures
Once chosen, n is a small exact integer, so the multiplication preserves significant figures exactly: 0.01250 mol × 2 is 0.02500 eq, four figures on both sides. No rounding, nothing accumulating. The risk on this pair is categorical rather than numerical — a wrong n produces an answer wrong by a small whole-number ratio, and that answer will look reasonable, carry the right number of digits, and pass every arithmetic check applied to it. Digits cannot catch it; rereading the reaction can. As for how many to keep, the mole value sets the ceiling and multiplying by an integer does not raise it. Where n itself is in doubt, report moles and state the reaction rather than publishing a figure that hides the assumption.
Worked Examples
HCl donates 1 H⁺, so n = 1; 1 mol = 1 eq.
H₂SO₄ donates 2 H⁺, so n = 2; 1 mol = 2 eq for full neutralization.
Ca(OH)₂ provides 2 OH⁻, so n = 2.
In acidic solution MnO₄⁻ gains 5 e⁻, so n = 5 for the redox reaction.
Common mistakes
Ionic charge assumed to set n
In a complexometric titration, EDTA binds a metal ion in a 1:1 ratio whatever its charge, so n is 1 for Ca²⁺ and 1 for Al³⁺ alike. Reaching for the ionic charge because it worked in a charge-balance calculation doubles or triples the equivalent count. The factor counts reacting units in the reaction being run, and here that unit is the entire ion.
Equivalents substituted into a balanced equation
Stoichiometric coefficients express mole ratios. Feed an equivalent count into a mole-ratio step and n gets applied a second time, since it is already baked into the number. Either convert back to moles before touching the balanced equation or stay in equivalents for the whole titration calculation — each system is self-consistent, and the error appears only at the join.
Per formula unit versus per atom
In a dichromate titration under acidic conditions one mole of Cr₂O₇²⁻ accepts six electrons, so n is 6 per dichromate ion but 3 per chromium atom. Both statements are true and they differ by a factor of two. Settle whether n is quoted per formula unit or per reacting atom before multiplying, and say which one in the record.