Find the smaller amount
The ingredient with fewer matching portions limits the gas.
Reaction Balloon
Balance reacting ingredient portions and account for gas trapped in a balloon.
Grades 3–5 · Chemistry
Your goal
Make 2 gas portions with no ingredient left over.
Reduced motion is on. The controls still update the scene.
0 gas portions are trapped in the balloon. Soda left 1; acid left 1. Total model mass stays 144 units, including 0 units of gas. Choose the ingredients and start the reaction.
Changing an ingredient prepares a new sealed trial. This ideal complete reaction uses baking soda and acetic acid in matching chemical portions. A soda portion has 84 model mass units and an acid portion 60; together they form 44 gas units and 100 liquid product units. Portions are not equal spoonfuls or a home recipe. Carrier water, heat and balloon pressure are omitted.
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Learn with Reaction Balloon
Choose portions of baking soda and acid, mix them, and watch the gas fill a balloon connected to a sealed flask. Reaction Balloon helps elementary learners reason about ingredients that run out first. One matching portion of each ingredient produces one gas portion, while extra ingredient remains in the flask. The inventory counts leftover ingredients, liquid products, and trapped gas so students can see that an expanding balloon does not create matter. Guided goals encourage balanced mixtures and purposeful excesses rather than simply adding more of everything.
What to look for
Count leftovers
Extra soda or acid remains when its partner runs out.
Include the balloon
The trapped gas is part of the conserved total mass.
For teachers and curious learners
Connect limiting ingredients with gas production and conserved total mass. Ask students to predict what will happen, change one setting, and explain what they observe. Learn gives a starting point. Practice and Challenge offer new goals with the same scene.
An ideal complete baking-soda and acetic-acid reaction uses matched chemical portions with relative masses 84 and 60, producing gas mass 44 and liquid product mass 100. Carrier water, temperature and balloon mechanics are omitted. These are not household spoonfuls.