Question

Which of the following is the BEST evidence that rusting is a chemical property rather than a physical property of iron?

a) Rust can form on iron.
b) Rust forms slowly.
c) Rust cannot turn back into iron.
d) Rust does not look the same as iron.

Answer 1

Rusting is a chemical property of iron, best evidenced by the fact that rust cannot turn back into iron (c). This irreversible change shows that a new substance with different properties has been formed.

Step-by-step explanation:

The question you've asked relates to the evidence that indicates that rusting is a chemical property of iron rather than a physical property. The correct answer to your question is c) Rust cannot turn back into iron. This is because once iron has combined with oxygen to form iron oxide, or rust, it has undergone a chemical change. This process is irreversible through normal physical means, which reflects a chemical property. In contrast, a physical property would be something that you can observe and measure without changing the chemical identity of the substance, such as the density of iron or its melting point.

Remember, chemical properties can only be observed as the substance is in the process of being changed into a different substance. The rusting of iron involves a chemical change where iron atoms lose electrons and combine with oxygen atoms from the environment, resulting in a new substance with different properties.