Classify each of the following as either a physical change or a chemical change. (a) Dissolving sugar in water
(b) Crushing rock salt
(c) Burning sulfur
(d) Digesting a chili dog

(a) Dissolving sugar in water  ⇒ physical change

(b) Crushing rock salt  ⇒ physical change

(c) Burning sulfur  ⇒ chemical change

(d) Digesting a chili dog ⇒ chemical change

Explanation:

Physical changes are those in which the substance does not alter its composition. They only involve changes of states of  matter and the chemical substance is stil the same after the change occurs. By other hand, chemical changes are those in which new subtances are formed. So, the subtance is not the same after the change.

(a) Dissolving sugar in water  ⇒ physical change; because we obtain a solution of sugar in water (sugar is stil sugar).

(b) Crushing rock salt  ⇒ physical change; because we obtain crushed salt, but the chemical composition of the salt is not altered.

(c) Burning sulfur  ⇒ chemical change; because sulfur is oxidized (chemical reaction) and new compounds are formed, for example sulfur dioxide.  

(d) Digesting a chili dog ⇒ chemical change; because the digestion process is produced by the action of hydrocloric acid, and new compounds are formed.

a chemical reaction happens

explanation: