If 273.1 mL of SO2 is allowed to react with 155.2 mL of O2 (both measured at 317 K and 46.8 mmHg ), what is the limiting reactant

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.