Why doesn’t matter “disappear” when fuel burns in an engine?

Answer	Because matter is conserved in normal chemical reactions. The fuel changes into different substances (mostly hot gases), but the total matter remains. WHY IT MATTERS: This helps you reason about exhaust gases, contamination, and closed-system behavior. AIRCRAFT EXAMPLE: Jet fuel in a turbofan becomes exhaust products, not “nothing.” MEMORY AID: Fuel → gases (it’s a change of form). EASA TIP: Look for wording like “created/destroyed” and choose “changed form/state.”
Difficulty	Medium
Lesson	2.1.1 Nature of Matter
Module	Module 2.1
Tags	ConservationMediumModule 2.1