Question

17 classify each of the following examples as a physical or chemical change by checking the box that applies.

example	physical change	chemical change
the golden gate bridge rusting	□	□
burning a piece of steel wool	□	□
sharpening a pencil	□	□
ketchup on a penny	□	□
mixing ice tea powder in water	□	□
combining milk and vinegar	□	□
baking chocolate chip cookies	□	□

Explanation:

Answer:

Boiling water to cook pasta: Physical Change (checked)
The Golden Gate Bridge rusting: Chemical Change (checked)
Burning a piece of steel wool: Chemical Change (checked)
Sharpening a pencil: Physical Change (checked)
Ketchup on a penny: Chemical Change (checked)
Mixing ice tea powder in water: Physical Change (checked)
Combining milk and vinegar: Chemical Change (checked)
Baking chocolate chip cookies: Chemical Change (checked)

(Note: For each row, the appropriate box (Physical Change or Chemical Change) is checked based on the nature of the change: physical changes involve no new substance formation, chemical changes do. Boiling water, sharpening pencil, mixing powder are physical. Rusting, burning, ketchup on penny (corrosion), combining milk/vinegar (curdling, new substance), baking cookies (chemical reactions) are chemical.)