Final answer:
To differentiate between physical and chemical changes, one must observe if the substance's identity changes. Boiling water is a physical change, while a nail rusting is a chemical change. Indicators like color or temperature changes suggest chemical changes, while physical changes pertain to the state or form of the substance without altering its identity.
Step-by-step explanation:
Experiments to test for physical and chemical changes involve observing alterations in matter to determine whether the identity of a substance has changed. For example, boiling water represents a physical change because the water molecules remain H₂O, despite changing state from liquid to gas. Conversely, a nail rusting is a chemical change due to the iron in the nail reacting with oxygen to form a new substance, iron oxide.
Physical changes include transformations like melting, freezing, and tearing, where substances retain their chemical identity. Chemical changes typically produce new substances, with indicators such as color changes, temperature changes, bubbles, or new solids forming. The experiment involving a volume change in oxygen gas from 10 mL to 11 mL due to temperature change showcases a physical change, as only the state, not the chemical identity, of oxygen is affected.
Understanding physical and chemical properties is fundamental for classifying changes effectively. For instance, properties like malleability, as seen when gold is stretched into wires, are intensive properties not dependent on the amount of substance and related to physical changes. Conversely, extensive properties like mass and volume are affected by a change in the quantity of the substance.