Final answer:
A flare cartridge will ignite when exposed to oxygen due to the combustion reaction that occurs between flammable substances and oxygen. This reaction is heightened in the presence of pure oxygen, as demonstrated by the increased combustion rate of a glowing splint in pure oxygen.
Step-by-step explanation:
When constructing or using a flare cartridge, understanding its reactivity with oxygen is crucial due to the principles of combustion chemistry. Combustion refers to the chemical reaction between a flammable substance and oxygen. In the presence of oxygen, a flare cartridge is designed to ignite and is used for signaling or illumination purposes. The principle behind this is exemplified by the behavior of a glowing wooden splint: when inserted into pure oxygen, its combustion rate increases significantly due to the higher concentration of oxygen. This explains why a flare cartridge will ignite in an oxygen-rich environment, as air itself contains approximately 20% oxygen gas.
The ignition of a flare cartridge epitomizes a rapid combustion reaction, which is evident when considered in a scenario where a glowing splint in pure oxygen bursts back into flame, five times more vigorously than in normal air. This can also apply to a flare cartridge, which, upon exposure to oxygen, will readily ignite due to the same combustion principles.