Chemistry Game

Chemistry Game is a virtual chemistry lab with 31 puzzles in three parts. Build molecules atom by atom so every atom has the right number of bonds, balance chemical equations until the atoms match on both sides, and mix acids and bases into a universal indicator to hit a target color. Play this chemistry game free in your browser, on desktop or on your phone, with no download or sign-up. It suits middle and high school chemistry.

How to play

Pick a part with the Build, Balance and pH Lab tabs at the top. You can switch at any time.

Build molecules

The goal box names a target, such as H₂O, CO₂ or CH₃OH. Tap an atom button and tap the bench to place that atom, or drag the button straight onto the bench. Drag from one atom to another to bond them. Tap a bond to raise it to a double bond, then a triple bond.

• Every atom must use exactly its valence: H 1, O 2, N 3, C 4, Cl 1. A double bond counts as two and a triple bond as three.
• A yellow badge on an atom shows how many bonds it still needs. The game refuses a bond that would go over an atom’s limit and tells you why.
• Sodium is a metal, so in table salt it makes a dashed ionic link to chlorine (Na+ and Cl-) instead of a shared bond.
• It is solved when the bench holds exactly the target’s atoms, all full and joined into one molecule.

Balance equations

Each puzzle shows an unbalanced equation such as CH₄ + O₂ → CO₂ + H₂O. Press + and − under each substance to change its coefficient, the number of molecules. A live atom-count table shows how many atoms of each element are on each side, with a check mark when a row matches. The puzzle is solved when every element matches and the coefficients are the smallest whole numbers, so 4, 2, 4 for hydrogen and oxygen is flagged until you reduce it to 2, 1, 2.

The 11 equations run from making water up to burning propane, rusting iron, respiration and photosynthesis.

pH lab

Each beaker holds water or a known amount of acid or base, with universal indicator mixed in. Tap a reagent button to add one portion, such as 1 mL of 0.1 M sodium hydroxide or 10 mL of water. The liquid changes color and a pH meter shows the exact value next to a 0 to 14 scale with the target range marked. The pH is calculated from the moles of acid and base and the total volume, so neutralizing 0.35 mmol of hydrochloric acid really does take 0.35 mmol of hydroxide.

Stars and saving

Every puzzle has a par: the fewest moves that can solve it. In Build each atom and each step of bond order is one move, in Balance each press of + or − is one, and in the pH lab each portion is one. Match par for three stars. Every puzzle’s answer is checked automatically, so all 31 can be solved. Each one ends with a short fact. Stars and unlocked puzzles are saved in your browser.

Tips

• Place the central atom first. Put the highest-valence atom in the middle and bond the rest around it.
• Count leftover bonds. If two neighboring atoms both still show a badge, they probably need a double or triple bond between them, as in O=C=O and N≡N.
• Balance C, then H, then O. In burning fuels, oxygen appears in two products, so leave O₂ until last.
• Do the mole math first. In the pH lab, add up the millimoles of H+ and OH- before you press anything. Near pH 7 a single drop makes a big jump.

FAQ

Is Chemistry Game free?

Yes. It’s free with no account and no install.

Can I play it on a phone or Chromebook?

Yes. Everything works with taps and drags on a touch screen or with a mouse. On a keyboard, H, C, N, O, L and A add atoms, Tab selects an atom, D raises its newest bond, the arrow keys change coefficients, keys 1 to 4 add reagents, Z undoes and R resets.

Is the chemistry accurate?

The valences, molecules and balanced equations are standard textbook chemistry, and the game checks each equation’s answer by brute force. The pH lab uses strong acids and bases, which split up completely in water, and computes pH from the concentrations. Real indicator shades vary a little by brand.

Want to look up an element while you play? Open our Interactive Periodic Table, or try more experiments in the Science Game lab.