Final answer:
When a colorless solution of lead (II) nitrate is added to a colorless solution of potassium iodide, a yellow solid called a precipitate is instantly formed. This formation of a precipitate suggests a chemical change.
Step-by-step explanation:
When a colorless solution of lead (II) nitrate is added to a colorless solution of potassium iodide, a yellow solid called a precipitate is instantly produced. This formation of a precipitate is an observation that suggests a chemical change has occurred. Precipitates are formed when two aqueous solutions react to produce a solid compound that is insoluble in water.