Question

Which is an example of a chemical change?

O water evaporating from a puddle
O cloth tearing when pulled
O wood forming sawdust when cut
O bread baking in an oven

Answer 1

Answer: when cut bread baking in an oven



Explanation:

Chemical change is defined as a change in which rearrangement of atoms take place and leads to formation of new substance.

Physical change is defined as a change in which change in shape, size or state of the substance takes place. No new substance is formed.

1. (not correct) water evaporating from a puddle: involves only a phase change from liquid to gaseous state and no new substances are formed.

2. (not correct) cloth tearing when pulled: involves only in stretching of fabric and no new substances are formed.

3. (not correct) wood forming sawdust involves only change in size and shape of wood and no new substances are formed.

4. (the correct answer) when cut bread baking in an oven involves oxidation of bread and the sugar gets converted to ethanol and carbon dioxide and thus represents a chemical change.


Important note: changing state (from liquid to gas, etc) does not solicit a chemical change.

Answer 2

Answer: bread baking in a oven and water evaporating in a puddle

Step-by-step explanation: