Question

1 which of the following examples is not a physical change?
a a person repainting a bicycle
b rain falling on a bicycle left outside
c rust forming on a bicycle chain
d cutting an old bicycle with a saw for scrap metal

Explanation:

A physical change alters the form or appearance of a substance without changing its chemical composition. Repainting (A) is a physical change as it only changes the appearance. Rain falling (B) is a physical change (water just contacts the bicycle). Cutting (D) is a physical change (changes the shape). Rusting (C) is a chemical change as iron reacts with oxygen and water to form iron oxide (rust), changing the chemical composition.

Answer:

C. Rust forming on a bicycle chain