Answer
a. physical change
b. chemical change
c. chemical change
d. physical change
Work Step by Step
a. Dissolving of sugar into water is a physical change as sugar and water retain their chemical identities.
b. Rusting of iron results in the transformation of iron into a new substance different from iron. This process of transformation is a chemical change that happens to iron resulting in a new substance, rust.
c. The process of burning requires oxygen, and in this process, new substance(s) are formed. As new substances are formed, the change is a chemical change. Burning of wood requires oxygen in the process, and wood is transformed in new substances, thus this is a chemical change.
d. Evaporation is the process of turning from aliquid into gas. This physical process changes the form of the matter, but it retains its chemical identity. Thus as alcohol evaporates it changes its form from liquid to vapor, but it retains its chemical identity.
