Chapter 2: Properties of Matter

1. Chapter 2: Properties of Matter Section 1

2. Chapter 2 Opening Demonstration • How are these two cans alike and different? • If we put these two drinks in water would they float or sink??? • Let’s Try!

3. Who is Right?? • This will work for any regular and diet drink!

4. Objectives • Describe physical & chemical properties. • Give examples of physical changes. • Explain that chemical changes form new substances. • Observe signs of chemical changes in an experiment.

5. Physical Properties • We use physical properties to describe an object or a person! • How would you describe these objects?

6. Matter has observable properties • Physical Properties the characteristics of a substance that can be observed without changing the identity of the substance. • Your senses can be used to detect physical properties. • Examples: Color, shape, size, texture, volume, mass.

7. How do you know which characteristics are physical properties? • Just ask yourself whether observing the property involves changing the substance to a different substance.

8. Density • Mass & Volume are two physical properties • Densityis a measure of the amount of matter present in a given volume of a substance. Density= Mass D= m Volume V

9. Can you Determine??? • How would you find the density of 200 g of clay with a volume of 100 cm3. • Density is a property of a substance that remains the same no matter how much of a substance you have!

10. Density • A glass marble has a volume of 5 cm3 and a mass of 13 g. What is the density of glass? • Answer: D= 2.6 g/cm3

11. Physical Changes • A change in any physical property of a substance, not in the substance itself.\ • Examples: • Stretching a Rubber Band • Ice melting

12. Chemical Properties

13. Up your nose….

14. Why is Lady Liberty’s nose so shiny? • It needs to be powdered? • NO! When Tori and Alex rub her nose, the oils on their skin remove the tarnish (a chemical reaction); revealing the untarnished alloy. Olis from their hands also protect the alloy from reacting with the air and forming more tarnish. • Do you think they pulled out an alloy booger?

15. Chemical Properties • Chemical Properties describe how substances can form new substances. • Examples: • Combustibility • Iron Rusting • Silver Tarnishing • Cooking (boiling Eggs) The only true indication of a chemical change is that a new substance has been formed.

16. Signs of a Chemical Change • You may or may not be able to observe many chemical changes. • If you observe 2 or more of these signs during a change, you are most likely observing a chemical change. • Production of an Odor • Change in Temperature • Change in Color • Formation of Bubbles • Formation of a Solid

17. Formation of an Odor • Some chemical changes produce smells. • The chemical change that occurs when an egg is rotting produces the smell of sulfur. • Thunderstorms also produce an odor. The odor is an indication that lightning has caused a chemical change in the air.

18. Lightning storm over Iraq~ Oct 07

19. Lightning over Camp Adder in Iraq

20. “God must hate this place as much as we do…” Captain Jason deFoor

21. Change in Temperature • Chemical changes often are accompanied by a change in temperature. • Example: Logs burning in a campfire

22. Change in Color • A change in color is often an indicator of a chemical change. • Example: Fruit may change color when it ripens.

23. Formation of Bubbles • The formation of gas bubbles is another indicator that a chemical change may have occurred. • Example: Antacid tablet in water

24. Formation of a Solid • When two liquids combine, a solid called a precipitate can form. • Examples: Shells of animals such as clams and mussels are precipitates. They are the result of a chemical change involving substances combining with substances from the creatures.

25. Review • What is a Physical Change? • Give an example. • What is a Chemical Change? • Give an example. • What is density? What is the formula? • What are the signs of a Chemical Change?