Give examples of sublimation.

Sublimation is a phase transition process in which a substance changes directly from a solid to a gas without passing through the liquid phase. This occurs when the substance's vapor pressure exceeds the atmospheric pressure at a specific temperature. Here are some examples of sublimation:

Dry Ice (Solid Carbon Dioxide): Dry ice is a common example of sublimation. At standard atmospheric pressure, dry ice changes from a solid to a gaseous state at around -78.5 degrees Celsius (-109.3 degrees Fahrenheit) without becoming a liquid.

Iodine Crystals: Iodine, a chemical element, can sublimate at room temperature. If you expose iodine crystals to the air, they gradually transition from a solid to a purple vapor without melting into a liquid.

Camphor: Camphor is a white, crystalline substance often used in medicinal ointments and as a household insect repellent. It sublimates at room temperature, emitting a distinct odor.

Naphthalene (Mothballs): Naphthalene, commonly used in mothballs, sublimates slowly over time, releasing a vapor that helps deter moths and insects.

Frozen Foods: In freeze-drying, a food preservation method, frozen foods are subjected to low pressures, causing the ice in the food to sublimate, leaving behind a dehydrated product with an extended shelf life.

Snow and Ice: In cold, dry conditions, snow and ice can sublimate directly into water vapor without melting into liquid water. This process is called "snow evaporation" or "dry snow sublimation."

Pharmaceuticals: Some pharmaceutical substances are purified through sublimation processes to remove impurities or isolate specific compounds.

Space Environment: In outer space, water ice on the surface of celestial bodies like comets can sublimate when exposed to solar radiation, transitioning directly from a solid to a gas.

These examples demonstrate the sublimation process in various contexts, from everyday materials like dry ice and mothballs to scientific and industrial applications.