Question

Why doesn't `CO_2` melt if you leave it out in the open?

Answer 1

When a solid mets into liquid, some of the intermolecular forces break, and when most of them break the liquid turns into gas.

Explanation:

`CO_2` is a non polar molecule and therefore, the only possible intermolecular interactions are London Dispersion Force (LDF) or also called Van der Waals forces which are considered weak forces, especially that `CO_2` is a small molecule.

When `CO_2` solid (dry ice) is heated (or left in the open air at `25^@C`), most of the intermolecular forces will break and `CO_2` molecules will be free and will become gaseous molecules.

Note that when a solid mets into liquid, some of the intermolecular forces break, and when most of them break the liquid turns into gas.