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Balance chemical equations

Move coefficients, count every atom and make matter balance on both sides.

Live model
REACTANTSPRODUCTSH2× 1O2× 1H2O× 1COUNT BOTH SIDES

1 H2+1 O21 H2O

The atom ledger updates instantly as each coefficient changes.

Set the coefficients

H2Reactant1
O2Reactant1
H2OProduct1
1 of 2 elements match

Description of this simulation

H already matches. O has 2 atoms before the arrow and 1 atom after it. Change coefficients, never subscripts.

Live atom ledger

Level 1
ElementBeforeAfter
  • H22
  • O21

What this reaction does

Hydrogen burns in oxygen to form water. The reaction releases enough energy to power a hydrogen fuel cell in reverse.

The rule that never changes

Change only the large coefficient before a formula. Changing a subscript changes the substance itself, so the simulator keeps every formula locked.

What this model shows — and what it simplifies

Each formula is parsed into its element counts, then multiplied by its coefficient. The simulator compares those computed totals on the two sides; the stored solution is used only by “Balance it for me”, never to judge a learner’s answer.

Where do we see this in real life?

Chemical plants use balanced equations to decide feed rates and predict product yield. From ammonia fertiliser to rocket propellant, an incorrect coefficient means wasted material, unsafe conditions or the wrong product quantity.