Balancing chemical equations – coefficients, molecule models and practice game

ChemistryReactions & RedoxAges 13–14

Use the up/down buttons in front of each formula to set coefficients until the number of atoms is the same on both sides of the equation. The Intro screen draws molecule models matching the coefficients, with a balance scale or bar chart for each element and a smiley face once the equation is balanced, using three familiar reactions (ammonia synthesis, decomposition of water, combustion of methane). The Game screen offers 3 levels × 5 equations from easy to hard, with 2 attempts per question, scoring and an optional timer. Adapted from the "Balancing Chemical Equations" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: Chemical equations