Formulae and equations

The tray is bookkeeping: it shows which atoms end up in which product, not how the reaction happens. In a real flame, molecules collide and bonds break and form in several steps; nothing on the tray burns.

Oxygen, hydrogen and nitrogen exist as molecules of two atoms, so the jars hold whole molecules. The models are not to scale, and their colours only label the elements.

The moves are slowed down. The real reaction of nitrogen and hydrogen is reversible and never turns all of them into ammonia; the tray only balances its equation.

With reduced motion, each move finishes at once.