For each of the following chemicals, indicate what a physical and chemical reaction might be. 

The first one has been done for you.

Baking Soda

• Chemical Change: Reacts with vinegar to produce carbon dioxide gas (acid-base reaction).

• Physical Change: Dissolves in water.

Water

• Chemical Change: Water can decompose into hydrogen and oxygen when electrolyzed.

• Physical Change: Ice melts into liquid water or water evaporates into steam.

Wood

• Chemical Change: Wood burns in oxygen to produce carbon dioxide and water vapor (combustion).

• Physical Change: Wood is cut or shaped (no new substance is formed).

Sugar

• Chemical Change: Sugar caramelizes when heated, forming a new substance.

• Physical Change: Sugar dissolves in water.

Milk

• Chemical Change: Milk turns sour due to bacterial action (producing lactic acid).

• Physical Change: Milk can be poured, or it can freeze into ice cream.

Paper

• Chemical Change: Paper burns (combustion), producing ash and gases.

• Physical Change: Paper can be torn or folded.

Lemon Juice

• Chemical Change: Lemon juice reacts with baking soda to release carbon dioxide gas.

• Physical Change: Lemon juice can be squeezed from the fruit (no new substance is formed).

Salt

• Chemical Change: Salt reacts with water to form a solution (dissolving is a physical process, but ionic bonds are disrupted).

• Physical Change: Salt crystals can be ground into smaller particles.

Gasoline

• Chemical Change: Gasoline combusts in an engine, producing carbon dioxide and water.

• Physical Change: Gasoline evaporates when exposed to air.

2.2: The Changes That Occur