What is dry ice comprised of?

Dry ice is composed of solidified carbon dioxide (CO2). When carbon dioxide gas is subjected to high pressure and low temperatures, it transitions into a liquid state and can then be converted into a solid form as it cools further. This solid form is what is known as dry ice.

Dry ice is commonly used as a refrigerant because it sublimates at -78.5 degrees Celsius (-109.3 degrees Fahrenheit), transitioning directly from solid to gas without passing through a liquid state. This characteristic makes it particularly useful for shipping perishable goods or maintaining low temperatures during specific applications in food storage and transport.

The other options do not accurately represent dry ice: frozen oxygen, for example, would not result in a solid form commonly used in air management; solidified ethanol does not have the same properties or applications; and liquid nitrogen is a completely different substance used for cooling and cryogenic applications, not related to dry ice at all.