55: 12
consider the reaction below.
hf + h2o → h30* + f"
which is an acid-conjugate base pair?
hf and h30*
hf and f
h20 and hf
h2o and f

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.

The answer would be solvent