Final answer:
A type of mask that heats up on application functions similarly to hand warmers that produce heat through an exothermic reaction when exposed to air, with salt as a catalyst for rapid heating, and supportive materials for even heat distribution.
Step-by-step explanation:
The type of mask that heats up after it is applied is similar to certain types of hand warmers that react with oxygen in the air to produce heat through an exothermic reaction. This reaction can take place when components like iron (Fe) and water (H₂O) inside the hand warmer, or in this case, possibly the mask, are exposed to oxygen (O₂), resulting in the formation of iron oxide (Fe₂O₃).
The presence of salt acts as a catalyst and helps to accelerate the reaction, generating heat more rapidly. Materials like cellulose, vermiculite, and activated carbon can be included to help distribute the heat evenly across the mask. Some products intended for warming, like hand warmers, additionally might use lighter fluid with a platinum catalyst, charcoal, or powered by electricity from batteries.