Chem Balancer
Level
1
Score
0
Streak
0
Best
0
Daily challenge

Adjust the coefficients so both sides have equal atoms.

(s) solid · (l) liquid · (g) gas · (aq) dissolved in water

How to play

1

Look at the atom counts below the equation — each shows left / right.

2

Use the − and + buttons to change the coefficients in front of each formula.

3

When every count matches (all green ✓), press Check. The simplest ratio scores most.

How to read a chemical equation

2H2 + O2 → 2H2O
Reactants Products
  • Coefficient: the big number — you can change this
  • Subscript: part of the formula — never change this
  • “→” means “reacts to form”

Worked example

H2 + O2 → H2O

Count the atoms on each side.

H2 + O2 → 2H2O

Oxygen doesn’t match. Put a 2 in front of H₂O.

2H2 + O2 → 2H2O

Now hydrogen doesn’t match. Put a 2 in front of H₂.

2H2 + O2 → 2H2O ✓

Count again — it’s balanced!

Key words

Reactant
Product
Coefficient
Subscript
Conservation of mass
Aqueous (aq)

Why balance equations?

Atoms are never created or destroyed in a chemical reaction — they are only rearranged. That's the law of conservation of mass. A balanced equation shows the same number of each atom on both sides, so it describes what really happens.
2H₂ + O₂ → 2H₂O

Reaction types

Synthesis
A + B → AB
2H₂ + O₂ → 2H₂O
Decomposition
AB → A + B
2H₂O₂ → 2H₂O + O₂
Combustion
fuel + O₂ → CO₂ + H₂O
CH₄ + 2O₂ → CO₂ + 2H₂O
Single replacement
A + BC → AC + B
Zn + 2HCl → ZnCl₂ + H₂

Elements in this game

Achievements

Part of the LLL Series OSS — free and open source, built by Live Laugh Love.

View on GitHub