I just need help this is hard

Which process describes vaporization that takes place below the surface of a liquid? condensation melting boiling evaporation

The following transition occurs at a molecular level for a substance. what transition corresponds to this change in microscopic structure? the carbon dioxide molecules on the left are in a regular, tightly packed pattern. after heating, it becomes much lower density. a. melting b. boiling c. sublimation d. freezing

Is hydrogen gas a reactant or product