Chapter 5

1. Chapter 5 Matter – Properties & Changes

2. Ch 5.1 – Physical Properties • Physical Property – any characteristic that can be observed without changing the composition of the substance

3. 1. Physical properties include characteristics gathered by the senses a) Examples: color, shape, smell, taste, texture

4. 2. Characteristics obtained by measurements a) Examples: length, width, height, mass, volume, density, weight, temp.

5. 3. State of Matter a) Examples: solid, liquid or gas dependant on temperature

6. 4. Physical properties can be used to identify unknown substances a) Density – amount of mass in a given volume; [ = mass(g) / volume(cm3) ]

7. b) A golf ball would have a greater density than a table tennis ball

8. c) One could determine the composition of a piece of jewelry by comparing its density with the density of a known substance such as gold or silver

9. 5. Some physical properties are size dependent a) Examples: length, width, height, volume, mass, weight 6. Some physical properties are size independent a) Examples: color, state, density

10. B. Physical Properties of Acids & Bases 1. Acids – have pH below 7 a) Properties include sharp smell and sour taste (**NEVER taste anything in a laboratory)

11. 2. Bases – have pH above 7 a) Properties include slippery texture and bitter taste

12. 3. Neutral – has pH of exactly 7 (not acidic or basic)

14. Ch 5.2 – Chemical Properties • Chemical Property – characteristic of matter that allows it to change to something new; cannot be observed without changing the composition

15. 1. Flammability – the ability to burn; how easily a substance will ignite and burn

16. 2. Oxidation – reactivity with oxygen

17. 3. Toxicity – degree to which a substance can damage living tissue

18. a) Chlorine compounds change the chemical properties of pool water making it more acidic to eliminate algae, bacteria and insects

19. B. Chemical Properties of Acids & Bases 1. Acids – can react with (corrode) metals a) Tomato sauce is acidic enough to corrode aluminum foil

20. b) Acid rain (nitric acid) can damage plant and animal tissues

21. c) Sulfuric acid is useful in industry but can cause severe burns on human skin

22. 2. Bases – used in cleaning products however if strong enough can also damage living tissue

23. 3. Salts – compounds made of metals and nonmetals when acids and bases react

24. Ch 5.3 – Physical & Chemical Changes • Physical Change – any change in matter where the identity of the substance stays the same

25. 1. Change in size or shape a) Ex: cutting watermelon into slices; changes size and shape but remains watermelon

26. 2. Change of state a) Solid to liquid (ice melting) b) Liquid to solid (water freezing) c) Liquid to gas (water boiling) d) Gas to liquid (condensation)

27. B.Chemical Change – a change that occurs when a type of matter is changed into a different type with new characteristics

28. 1. In a chemical change materials are formed that are different from the starting materials 2. A chemical change cannot easily if at all be reversed

29. 3. Examples include metal rusting, copper turning green (patina), wood paper or gas burning, food digesting, baking a cake, explosion of fireworks

30. 4. Signs of chemical changes a) Release or absorption of energy in the form of light, heat or sound

31. b) Formation of a gas or solid (precipitate) not due to change of state

32. c) Change in color, smell or taste

33. C. Physical & Chemical Changes in Nature 1. Physical – weathering & erosion of rocks due to weather and animals

34. 2. Chemical – weathering of rocks due to acid rain; color change of leaves in Fall