Carbon dioxide

A carbon dioxide compound with the chemical formula CO2 and a chemical formula of 44.0095. It is a colorless, odorless or colorless gas with a slightly acidic aqueous solution at room temperature and pressure. It is also a common greenhouse gas and a component of air (0.03% -0.04% of the total volume of the atmosphere).

In terms of physical properties, carbon dioxide has a melting point of -56.6 ℃ (527kPa) and a boiling point of -78.5 ℃. It has a higher density than air (under standard conditions) and is soluble in water.

In terms of chemical properties, carbon dioxide has inactive chemical properties and high thermal stability (only 1.8% decomposition at 2000 ℃). It cannot be burned and usually does not support combustion. It belongs to the category of acidic oxides and has the properties of acidic oxides. It reacts with water to produce carbonic acid, which is the anhydride of carbonic acid.

Carbon dioxide can generally be obtained by calcining limestone at high temperatures or reacting limestone with dilute hydrochloric acid. It is mainly used for refrigerated perishable foods (solid), as a refrigerant (liquid), manufacturing carbonated soft drinks (gaseous), and as a solvent for homogeneous reactions (supercritical state). Regarding its toxicity, research has shown that low concentrations of carbon dioxide are not toxic, while high concentrations of carbon dioxide can cause animal poisoning.

(Basic principle of carbonated beverages) Make purple litmus solution turn red, and a certain amount of CO ₂ can make clear lime water (Ca (OH) ₂) become turbid. It can be used in experiments on the production of carbon dioxide by respiratory products and can also support magnesium band combustion