Question

compare chemical changes and physical changes
a. define and give an example of a physical change
b. define and give an example of a chemical change

Explanation:

a. Physical Change

A physical change is a transformation that alters the physical properties (such as shape, size, state) of a substance without changing its chemical composition. For example, when ice melts into water, the chemical formula \(H_2O\) remains the same. The change is only in the state (from solid to liquid).

b. Chemical Change

A chemical change is a process in which one or more substances are converted into new substances with different chemical compositions. This involves breaking and forming chemical bonds. For instance, when iron rusts (\(4Fe + 3O_2+6H_2O
ightarrow 4Fe(OH)_3\)), a new substance (rust - iron hydroxide) is formed with a different chemical identity than iron (\(Fe\)) and oxygen (\(O_2\)).

Answer:

a. A physical change alters physical properties without changing chemical composition. Example: Ice melting (\(H_2O(s)
ightarrow H_2O(l)\)).
b. A chemical change converts substances into new ones. Example: Iron rusting (\(4Fe + 3O_2+6H_2O
ightarrow 4Fe(OH)_3\)).