The conjugate pair for a strong base is - O a strong base
O a weak acid
a strong acid
O a weak base

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.

Your question is not clear but if you can explain yourself i would be glad to .  just trying to : ))

Answer//the law of conservation of mass.;