In equilibrium problems, you rarely know all the concentrations at equilibrium — but you don't need to. A single known change, combined with the stoichiometric coefficients, cascades through the entire system. Drag the slider to adjust how much A is consumed, and watch the ICE table auto-fill based on the reaction 2A + B ⇌ 3C.
Drag to set the change in [A] — the ratios do the rest
| 2A | B | 3C | |
|---|---|---|---|
| I | 1.00 | 1.00 | 0.00 |
| C | 0.00 | 0.00 | +0.00 |
| E | 1.00 | 1.00 | 0.00 |
When the reaction runs forward, reactants A and B are consumed and product C is formed. The change row shows negative values for A and B (they decrease) and positive for C (it increases). The stoichiometric coefficients — 2:1:3 — determine the exact ratio of these changes. If 0.40 M of A is consumed, then 0.20 M of B must also be consumed (half as much, because B's coefficient is 1 while A's is 2), and 0.60 M of C is produced (1.5 times the A change, because C's coefficient is 3 while A's is 2). This ratio is locked by the balanced equation and never changes, regardless of direction or how far the reaction proceeds.
The change row of an ICE table obeys the stoichiometric ratio of the balanced equation — one known change determines all others through simple proportion, and row 3 equals row 1 plus row 2 to give equilibrium concentrations you substitute into K.