Question

question 5
which option is an example of a chemical reaction?
metal rusting
water freezing
snow falling
ice melting

Explanation:

A chemical reaction involves the formation of new substances. Metal rusting (e.g., iron rusting: \( \ce{4Fe + 3O_2 + 6H_2O -> 4Fe(OH)_3} \)) forms rust (a new compound), while water freezing, snow falling, and ice melting are physical changes (state changes, no new substance).

Answer:

A. metal rusting