Dry ice, ammonium chloride, naphthalene balls and camphor, all these compounds are an example of:

Explanation

These are standard textbook examples of substances that pass from a solid to a vapour on heating. Dry ice, naphthalene and camphor undergo sublimation. Heated ammonium chloride also dissociates into ammonia and hydrogen chloride, which recombine on cooling; school texts commonly include this in sublimation demonstrations.