The available reactant amounts determine how many complete reaction packets are possible in this discrete model. The limiting reactant runs out first, while an excess reactant remains. Counting atoms separately checks conservation more reliably than comparing only the number of molecules, which can change. The depicted reaction is virtual; no ignition or gas-handling instructions are provided.
Matter and chemistry · Discover & try
Can atoms disappear in a chemical reaction?
Reading level 4 of 5 · FluentChange
Word help
reactant
A starting substance in a reaction.
product
A substance formed by a reaction.
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See how it works
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Virtual atom bookkeeping only; no gas mixing, ignition, reaction-rate or laboratory procedure is modelled.
What to look for
- Each element count is conserved
- Molecule counts can change
- An excess reactant can remain
Explain what you noticed
There are 3 H2 groups and 2 O2 groups. After one complete 2 H2+O2 packet reacts, what remains unused?
Keep this idea: Count each element before and after rearranging the groups.
Follow the sources
- American Chemical Society — What Is a Chemical Reaction?
- American Chemical Society — Controlling the Amount of Products
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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