1, prepare materials
To make dry ice, you need to prepare some materials first. These materials include carbon dioxide gas, closed containers and cooling devices. Carbon dioxide gas can be bought in many places, such as science laboratories, goods stores or online stores. The closed container can be any container that can be sealed, such as a glass bottle or a plastic can.
2, charging carbon dioxide gas
Put the closed container in a safe place, then open the valve of carbon dioxide gas, connect the gas to the closed container with a hose, and slowly inject the gas into the container. In the process of gas injection, be careful not to inject too fast to avoid excessive pressure. When the carbon dioxide gas in the container reaches two thirds, the injection is stopped.
Step 3: cool the container.
Put the closed container into the cooling device and ensure that the container is completely immersed in the cooling medium. The temperature of the cooling device should be kept below minus 78 degrees Celsius, which is the lowest temperature for dry ice formation. Wait for a while until the carbon dioxide gas in the container is completely frozen into a solid.
Step 4 take out the dry ice
When the carbon dioxide gas in the container is completely frozen into a solid, carefully take out the container. Because dry ice is very cold, be careful not to touch the surface of dry ice when taking out the container to avoid frostbite of the skin.
Introduction of dry ice
Physical properties: white crystal, easy to sublimate at room temperature, high vaporization heat. When sublimating under normal pressure, the surrounding temperature will drop rapidly. Therefore, when dry ice sublimes in the air, it will liquefy or even further condense the water vapor in the air, and the formed water vapor droplets or ice crystals will adhere to the dust in the air to form white smoke. The crystal structure of dry ice is a simple cube and belongs to molecular crystal. Single carbon dioxide molecules are located at the apex and face center of the cube in different orientations and pile up to form dry ice crystals.
Chemical properties: dry ice is stable in chemical properties, odorless, nontoxic, nonflammable and does not support combustion. However, if the carbon dioxide content in the air is too high, it will stimulate the respiratory system and cause the danger of suffocation (that is, hypoxia). Carbon dioxide has high thermal stability. Dry ice is an acidic oxide, which has the commonness of acidic oxides and reacts with water to produce carbonic acid.