Question

20. Which activity is an example of a chemical change?

(1) dissolving table salt in water
(3) hammering aluminum into thin sheets
(2) melting gold to make jewelry (4) burning wood to produce ashes​

Answer 1

Answer is option 4.

A chemical change means the actual compounds involved change chemically. When you burn wood, you convert wood an oxygen into carbon dioxide, carbon monoxide, carbon (ashes), and water.

The other options describe physical changes. The compound doesn’t change, just its physical state.