Sulfuric acid (h2so4) is spilled on a laboratory bench. which chemical would be useful for neutralizing the acid

Sulphuric acid (H2SO2) is a dibasic acid. It generated H+ ions when dissolved in water. In order to neutralize an acid, a base containing hydroxy ion (OH-) will be required. 

NaOH, Ca(OH)2, KOH, etc. can be used to neutralize H2SO4.

If NaOH is used as a base, following reaction is initiated.

2NaOH     +      H2SO4      →     Na2SO4     +     H2O     
 (base)                (acid)                  (salt)

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.