Super quick question: intermolecular forces allow which of the following substances to be the least fluid: calcite or glass?

I would say glass since calcite's intermolecular forces are London dispersions, and glass is made with SiO2, a covalent tetraedric structure (way stronger). Hope it helps you

Nonmetals usually react by gaining electrons

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.