1. Chapter 20 Properties and Changes of Matter

2. I. Physical and Chemical Properties A.Physical Property – a characteristic that you can observe without changing or trying to change the composition of a substance (How something looks, smells, sounds, or tastes are all examples of physical properties.)

3. 1. Using your senses a) Some physical properties describe the appearance of matter. -see size and shape, touch and feel texture, smell the odor, or taste the flavor.

4. 2. State of Matter a) solid – has a definite shape and a definite volume b) liquid – has no definite shape and a definite volume c) gas – has no definite shape and no definite volume 3. Size-Dependent Properties a) volume – the amount of space an object takes up b) mass – how much matter an object has

5. 4. Size-Independent Properties a) Density – the amount of mass in a given volume b) Solubility – the number of grams of one substance that will dissolve in 100 grams of another substance c) Melting Point – the temperature at which a solid changes into a liquid d) Boiling Point – the temperature at which a liquid changes into a gas e) Magnetic Properties – some materials pull iron towards them Link to Density lab worksheet

6. B.Chemical Properties -Chemical Property – a characteristic that cannot be observed without altering the substance -The ability of a substance to undergo a change that alters its identity.

7. II. Physical and Chemical Changes A.Physical Change -Physical Change – the form or appearance of matter changes but not the composition 1. Changing Shape 2. Dissolving

8. 3. Changing State a) vaporization – process of changing a liquid to a gas b) condensation – process of changing a gas to a liquid c) sublimation – process of changing a solid directly to a gas d) deposition – process of changing a gas directly to a solid

9. B.Chemical Changes -Chemical Change – substances are changed into different substances. The composition of the substance changes -ex. Rust, leaves changing color C.Signs of Chemical Changes 1. Change in color a) ex. Something burnt, half eaten apple turning brown, fireworks

10. 2. The release of energy or gain of energy by an object a) ex. Pancakes take in heat energy, a firefly’s light, burning something 3. A change in odor a) ex. Rotten eggs 4. The formation of a gas or a solid a) ex. Bubbles from an antacid tablet 5. Substances cannot be changed back into original substances.

11. D.Conservation of Mass -The Law of Conservation of Mass – the total mass of the matter is the same before and after a physical or chemical change