Describing Matter

1. Describing Matter Properties used to describe matter can be classified as extensive or intensive. • An extensive property is a property that depends on the amount of matter in a sample. • An intensive property is a property that depends on the type of matter in a sample, not the amount of matter.

2. 2.1 Describing Matter • Extensive properties depend on amount. • The mass of an object is a measure of the amount of matter the object contains. • The volume of an object is a measure of the space occupied by the object. The big ball has moremass and volume than the little ball.

3. 2.1 Describing Matter Intensive Properties The hardness of a bowling ball is an example of an intensive property.

4. Is flammability an extensive or intensive property?

5. 2.1 Identifying Substances Matter that has a uniform and definite composition is called a substance. A substance is pure.

6. 2.1 Identifying Substances Every sample of a given substance has identical intensive properties because every sample has the same composition. Example- Every sample of pure water is a clear, odorless, liquid at room temperature. The water will boil at 100ºC and freeze at 0ºC. These properties are intensive because they do not depend on how big the sample is.

7. 2.1 Identifying Substances • A physical property is a quality or condition of a substance that can be observed or measured without changing the substance’s composition. • Hardness, color, conductivity, and malleability are examples of physical properties.

8. 2.1 Identifying Substances

9. 2.1 States of Matter • What are three states of matter? • Three states of matter are solid, liquid, and gas.

10. 2.1 States of Matter • Solids • A solid is a form of matter that has a definite shape and volume.

11. 2.1 States of Matter • Liquid • A liquid is a form of matter that has an indefinite shape, flows, yet has a fixed volume.

12. 2.1 States of Matter • Gases • A gas is a form of matter that takes both the shape and volume of its container. • The gas state is the only state of matter that is compressible.

13. 2.1 States of Matter • Vapor describes the gaseous state of a substance that is generally a liquid or solid at room temperature, as in water vapor.

14. States of Matter Macroscopic qualities- volume, shape, and compressibility Microscopic properties- Relate the states of matter to the arrangements of their particles.

15. States of matter- the 3 forms at which matter exists Solid- particles are tightly packed in a rigid structure. Has a shape and a fixed volume! Liquid- particles are very close but can move around each other. Takes the shape of its container, but has a fixed volume. Gas- particles are far apart and have little effect on each other. Has no fixed shape or volume.

17. Substances go from solid to liquid to gas as energy increases.

18. 2.1 Physical Changes • During a physical change, some properties of a material change, but the composition of the material does not change. • As gallium melts in a person’s hand, the shape of the sample changes, but the composition of the material does not change.

19. 2.1 Physical Changes • Physical changes can be classified as reversible or irreversible. • All physical changes that involve a change from one state to another are reversible. • Cutting hair, filing nails, and cracking an egg are examples of irreversible physical changes.

20. 2.1 Section Quiz. 1.Which of the following would be described as an extensive property of matter? • temperature • color • mass • hardness

21. 2.1 Section Quiz. 2. Which properties can be observed without changing the composition of a substance? • all properties of a substance • intensive properties • chemical properties • physical properties

22. 2.1 Section Quiz. 3. Match the states of matter with the following descriptions: (1) takes the volume and shape of its container (2) has a definite shape and volume (3) has a definite volume but an indefinite shape • (1) liquid, (2) solid and (3) gas • (1) gas, (2) solid, and (3) liquid • (1) gas, (2) liquid, and (3) solid