The reason why it s better to refrigerate food with dry ice than with ice is:

One is temperature. Dry ice is solid carbon dioxide, the solid becomes gaseous sublimation and endothermy, so that the outside temperature is low (it should be able to reach minus 78 degrees), ice is solid water, the solid state becomes liquid liquefaction and endothermy, and the temperature of the ice-water mixture is counted as a crystal, and the temperature does not change when it melts - it is zero degrees). Because dry ice sublimation and endothermy make the outside temperature low, rapid freezing will not cause frostbite to juicy food, and the slow freezing speed of ice will cause frostbite, and food cells may ulcerate and retain juice ...... after thawingThen it's easy to get corrupt.

The second dry ice sublimates into gaseous carbon dioxide, which isolates oxygen and makes food unspoilable. Carbon dioxide is relatively stable and rarely reacts with food. Ice turns into water, and the participation of water allows many reactions to proceed, which may accelerate the spoilage of food.

Dry ice is a solid of carbon dioxide. It absorbs a lot of heat during sublimation, so it can be used to refrigerate food. Carbon dioxide, on the other hand, is stable and does not spoil food.

Ice is water, it cannot prevent food from reacting with oxygen in the air and spoiling, and at the same time, because of the participation of water, many reactions will be carried out, so that food will deteriorate faster. So dry ice is better than ice.

Dry ice, solid carbon dioxide, is much cooler than ice, and the lower the temperature, the better the refrigeration.

Because dry ice is carbon dioxide, it does not oxidize with food.

1. Application in the beauty industry.

Some doctors use dry ice for pimples, which is the so-called freezing. Because it will slightly freeze the **.

There is a ** pimple freezing material that is mixed with ground dry ice and acetone and sometimes mixed with some sulfur. Liquid nitrogen and solid dry ice can also be used as materials for freezing**. Freezing ** can reduce inflammation, and some time ago the news reported that Liu Xiang used this kind of freezing ** to ** pimples on his face.

This method can reduce the appearance of acne scars, but it is not used to remove scars.

2. The application of dry ice in the food industry.

a Dry ice cubes in wine, cocktails or beverages are cool and pleasant to drink.

b Dry ice is added when making ice cream, and the ice cream does not melt easily. Dry ice is particularly suitable for refrigeration of takeaway ice cream.

C star hotels, restaurants to make seafood specialties, when the table is served with dry ice, can produce white smoke landscape guess skin, improve the level of the banquet such as making lobster sashimi.

d Frozen and refrigerated lobster, crab, shark fin and other seafood. Dry ice does not dissolve water, it is cleaner and cleaner than water ice, and is widely used in Europe, the United States, Japan and other countries.

3. Application of dry ice in the field of refrigerated transportation.

a. Low-temperature frozen medical use and low-temperature transportation of special drugs such as plasma and vaccines.

b Electronic cryogenic materials, long-distance and short-distance transportation of precision components.

c. Preservation and transportation of high-end food, such as high-grade beef and mutton.

4. Application in the field of entertainment.

It is widely used in the production of smoke on stage, theater, film and television, wedding, celebration, party effect, etc., such as some programs of the National Theater are made of dry ice.

Dry ice applications in other fields.

5. Application in the fire protection industry.

Dry ice is used for fire fighting, such as some low-temperature fire extinguishers, but dry ice is less used in this area, that is, the market degree is low;

a.Dry ice is a solid state of carbon dioxide.

b.Dry ice is liquefied and then vaporized after heating, and there is no residue of coarse sources.

c.Dry ice is non-toxic and odorless, and has a sterilizing effect.

d.Dry ice has a temperature well below 0 and is often used to freeze objects or maintain low temperatures.

Correct Answer: Lithology: B

In fact, there are a few more points:

1.Dry ice absorbs heat when it sublimates, lowering the temperature of food and preserving its freshness.

2.Dry ice does not leave a liquid after sublimation, only gas, and does not make the food moist.

3.After the sublimation of dry ice, carbon dioxide is produced, which is denser than air, and it will be attached to the surface of the food, so that the food is isolated from oxygen and prevent the food from rotting (junior high school knowledge).

The characteristics of freeze-drying do not include (d).

a.Suitable for heat-sensitive drugs BDry c. at low temperaturesDry in high vacuum conditionsThe dried finished product has a high moisture content and is not easy to store for a long timeThe dried finished product is loose and easy to dissolve.

Freeze Drying Knowledge Extension:

Freeze drying is the use of the principle of ice crystal sublimation, in a highly vacuum environment, the moisture of the frozen food materials is directly sublimated from the ice solid to steam without the melting of ice, the moisture in the general vacuum drying materials is converted into vapor in the liquid state and the food is dried, so freeze drying is also called freeze sublimation drying.

Freeze drying is different from ordinary heating drying, the moisture in the material is basically sublimated and dried on the frozen solid surface below 0, and the substance itself remains in the ice rack when frozen, so the volume of the dried product remains unchanged, loose and porous. Ice needs heat during sublimation, and the material must be properly heated, and a certain temperature gradient must be formed between the heating plate and the sublimation surface of the material, so as to facilitate the smooth progress of heat transfer.

The main advantages are:

1) The dried material retains its original chemical composition and physical properties: such as porous structure, colloidal properties, etc.; Consumes less heat than other drying methods. The disadvantage is that it is more expensive and cannot be widely adopted. It is used to dry antibiotics, vegetables and fruits, etc.

2) The water-containing biological sample is frozen and fixed, and the water in the sample is directly sublimated by ice under the condition of low temperature and high vacuum to achieve the purpose of drying.

a. Dry ice is used for refrigerated food, which is the use of dry ice to sublimate and absorb heat, which is a physical property; b. Hydrochloric acid is used to remove rust, which is the property of hydrochloric acid to react with metal oxides, which is a chemical property; c. Oxygen is used for medical treatment, which is the property of using oxygen to help breathing, which is a chemical property; d. Soda ash is used for steaming steamed bread, which is the property of using sodium carbonate to react with acid, which is a chemical property; So choose A