Do Now #7

1. Do Now #7 • A physical change occurs when a substance changes form, but stays the same. • A chemical change occurs when a substance changes into a new, different substance. • 1. In which Station Activities did you observe physical changes? • 2. In which Station Activities did you observe chemical changes?

2. Physical vs. Chemical • Physical Property • characteristics observed without changing the identity of the substance • Characteristics such as color, density, odor • Chemical Property • describes the ability of a substance to undergo changes in identity

3. Physical vs. Chemical • Lets think about the penny. What is the penny made out of? • Please tell me you didn’t say just copper! • Lets take a look at what the penny has done over the years. • Composition? • Why would the penny change (think of physical properties, as well as chemical properties?

4. B. Physical vs. Chemical physical chemical physical physical chemical • Examples: • melting point • flammable • density • magnetic • tarnishes in air

5. Classify Each of the following as Physical or Chemical Properties • The boiling point of ethyl alcohol is 78°C. • Physical property – describes inherent characteristic of alcohol – boiling point • Diamond is very hard. • Physical property – describes inherent characteristic of diamond – hardness • Sugar ferments to form ethyl alcohol. • Chemical property – describes behavior of sugar – forming a new substance (ethyl alcohol)

6. Changes in Matter • Physical Changes are changes to matter that do not result in a change of the fundamental components that make that substance (CHANGE IN CONDITION) • State Changes – boiling, melting, condensing • Chemical Changes involve a change in the fundamental components of the substance (CHANGE IN MATERIAL) • Produce a new substance • Chemical reaction • Reactants  Products

7. It’s a physical change if • It changes shape or size • It dissolves.

8. It’s a physical change if... • It changes phase (freezes, boils, evaporates, condenses)

9. It’s a chemical change if…. • It burns • Temperature changes without heating/cooling

10. It’s a chemical change if... • It bubbles (makes a gas)

11. It’s a chemical change if... • It changes color • It forms a precipitate

12. What kind of change is it if someone... • Tears up paper? • Physical change • Mixes salt and water? • Physical change

13. What kind of change is it if someone... • Burns paper? • Chemical change • Evaporates salt water? • Physical change

14. Table salt is stirred into water (left), forming a homogeneous mixture called a solution (right)

15. No chemical change occurs when salt water is distilled

16. What kind of change is it if someone... • Mixes vinegar and baking soda? • Chemical change

17. Physical vs. Chemical chemical physical chemical physical physical • Examples: • rusting iron • dissolving in water • burning a log • melting ice • grinding spices

18. Classify Each of the following as Physical or Chemical Changes • Iron is melted. • Physical change – describes a state change, but the material is still iron • Iron combines with oxygen to form rust. • Chemical change – describes how iron and oxygen react to make a new substance, rust • Sugar ferments to form ethyl alcohol. • Chemical change – describes how sugar forms a new substance (ethyl alcohol)

19. PHYSICAL CHEMICAL CHANGE New form of old substance. No new substances formed. Old substance destroyed. New substance formed. PROPERTIES Description by senses – shape, color, odor, etc. Measurable properties – density, boiling point, etc. List of chemical changes possible. Properties of Matter