How are covalent molecules named?

Covalent compounds are named by using numerical prefixes to identify the number of atoms in the molecule. For example Carbon Dioxide CO2 and Carbon Monoxide CO . ... Drop the double vowel for the prefix and the element of the second element in the compound

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.