Crude petroleum is processed in two main stages at a refinery:
• Stage 1: Fractional distillation separates the mixture into gasoline, kerosene, and other fractions based on boiling points.
• Stage 2: Catalytic cracking converts large hydrocarbon molecules in heavy oils into smaller molecules suitable for gasoline.
Which of the following identifies the stage(s) in which a chemical change occurs?
a) Both Stage 1 and Stage 2
b) Stage 2 only
c) Stage 1 only
d) Neither Stage 1 nor Stage 2