Objective: May 29

1. Narez Objective: May 29 • IWBAT demonstrate my ability to distinguish between physical and chemical changes through experimentation during the lab. • BRAINJOG: (ANSWERS ONLY) • Using yesterday’s notes, write two things that chemists do.

2. Intro to Chemistry

3. Narez It is a branch of science, what really is science? • It’s more than collecting facts, figures, graphs and tables. • It’s examining our universe, asking and answering questions • Questions that are testable • Results from experiments await for another scientist to disprove or improve on an idea, hypothesis, or prediction. • Science is Inquiry – Discovering the unknown

4. Narez What is Chemistry? • Study of Matter and Energy • What’s matter? -__- • Matter is ANYTHING that takes up space and has mass.

5. Narez Chemists study chemical reactions. • Chemical reactions are changes from one substance to another. • Matter may be a pure substance or a mixture of pure substances. • Substances are made of elements and many elements put together form compounds.

6. Narez Chemists Analyze Substances • Solids • Liquids • Gases

7. Narez Chemists synthesize new substances From the Ecology Unit, why is ammonia important for our environment?

8. Narez Chemists measure physical properties • Melting Point • Boiling Point • Strength in bonds between atoms • Rates of reactions Viagra

9. Narez We convert one unit to another often… • 1 kg = 1, 000 grams • 1 kg = 103 grams You can swap numbers (reciprocal) to switch the sign (positive or negative) of the exponent: 1 kg or 10-3 kg 103g 1g Conversion Factor

10. Narez Prefixes (Memorize) • King Henry Died Drinking Chocolate Milk

11. Narez Base Units for length is in meters EXAMPLE 1: 1 mm makes up how many centimeters. Convert to base first, cancel until you get what you want to end up with: 1mm x 10-3m x 1 cm = 0.00005 cm 1 mm 10 -2 m

12. Narez Put the exponent on the base! • 3 bases to memorize • For length its in METERS (m) • For mass its in GRAMS (g) • For volume its in METERS CUBED (m3)

13. Narez Try • If an inch equals 2.54 cm, how many meters are found in a 35 inch piece of wood. • 35 in x 2.54 cm x 10 -2 m = 0. 89 m 1 in cm

14. Narez Try one more time • Convert 15 km into centimeters

15. Narez A substance may undergo a chemical or physical change

16. Narez Chemical Change • Definition: A substance changes and forms a new substance with new properties. It’s usually not reversible. • Example: • iron rusting (iron oxide forms) • gasoline burning (water vapor and carbon dioxide form) • eggs cooking (fluid protein molecules uncoil and crosslink to form a network)) • milk souring (sour-tasting lactic acid is produced)

17. Narez Physical Change • Definition: A change in its structure by re-arranging it’s molecules but no new substances form. • whipping egg whites (air is forced into the fluid, but no new substance is produced) • boiling water (water molecules are forced away from each other when the liquid changes to vapor, but the molecules are still H2O.) • dissolving sugar in water (sugar molecules are dispersed within the water, but the individual sugar molecules are unchanged.) • dicing potatoes (cutting usually separates molecules without changing them.)

18. Narez On your notes sheet, make the following table under “Lab Table”