At room temperature, when the carbon dioxide gas is pressurized to about 60' 10 1325Pa, part of the steam is cooled to about -56℃, which will freeze into snowflake-volt solid carbon dioxide. The gasification heat of solid carbon dioxide is very high, which is 364.5 Joule/g at -60℃. During atmospheric gasification, the ambient temperature can be reduced to about -78℃ and no liquid will be produced, so it is called "dry ice". Ordinary dry ice is lumpy or granular.
Dry ice is mainly used as refrigerant, which is used in low temperature experiment, artificial rainfall, deburring of molded rubber parts and high-speed grinding. Dry ice can also be used as a quick-frozen preservative for food. In the laboratory, the mixture of dry ice and a volatile liquid (such as ether, acetone or chloroform) can form a low temperature bath of about -77℃.
Extended data:
1. Application of dry ice in food field;
Eating dry ice, adding dry ice to wine, cocktails or drinks, is cool and delicious when drinking, and the cup is full of smoke, which is very pleasant. Dry ice has been widely used in the preservation of aviation food; Dry ice is added when making ice cream, so the ice cream doesn't melt easily. Dry ice is especially suitable for cold storage of takeaway ice cream. ?
Seafood dishes made by star-rated hotels and restaurants, with dry ice, can produce white smoke landscape and improve the banquet level, such as making lobster sashimi. Lobster, crab, shark's fin and other seafood are frozen and refrigerated. Dry ice will not change water, and it is cleaner than water-cooled storage. Widely used in Europe, America, Japan and other countries. ?
2. Application of dry ice in medical field: low-temperature freezing medical use.
3. Application of dry ice in entertainment field;
Widely used in stage, theater, film and television, wedding, celebration, party effect and so on to make smoke; ? Application of dry ice in industry Carbon dioxide is a common compound in the air. Carbon reacts with oxygen to produce its chemical formula CO2. A carbon dioxide molecule consists of two oxygen atoms and one carbon atom through valence bond. At room temperature, it is a colorless and odorless gas, and its density is higher than that of air. Soluble in water, can react with water to generate carbonic acid, and does not support combustion.
Solid carbon dioxide, commonly known as compressed dry ice, is considered to be the main source of aggravating the greenhouse effect.
Baidu encyclopedia-dry ice