1. Chapters 1 & 2 Matter and Change

2. What is Chemistry? Chemistry - Defined as the study of composition, structure, and properties of matter Matter - 1. Has mass 2. Takes up space 3. Exists in four states: solid, liquid, gas, plasma

3. Is it matter??? 1. Rocks 2. Baby powder 3. Milk 4. Air 5. Light 6. Dust 7. Love 8. Cells 9. Atoms 10. Fire 11. Smoke 12. Salt 13. Mars 14. Jupiter 15. Steam 16. Rotten apples 17. Heat 18. Sound waves 19. Water 20. Bacteria 21. Oxygen stars 22. Gravity 23. Magnetic force 24. Dissolved sugar 25. Electricity

4. Chemistry cont. Chemical – any substance that has a definite composition. Ex.) Nitrogen, Oxygen, Water, Hydrochloric acid

5. Classification of Matter 1. Pure substance *fixed composition *all samples have identical properties *2 kinds of pure substances 1. Elements (one type of atom) 2. Compounds (two or more types of atoms) Atom – the smallest unit of an element

6. Compound or Element?

7. Classification of Matter, cont. 2. Mixture *Blend of 2 or more kinds of matter *Each part retains its unique properties A. Homogeneous (uniform) - also called solutions B. Heterogeneous (not uniform)

9. Properties of Matter Physical Property *Property that can be observed/measured without altering the substance’s composition ex/ melting point, color, density Chemical Property *Property that relates to a substance’s ability to change into new/different substances ex/ability of iron to rust

10. Properties of Matter, cont. Extensive properties – depends on amount of matter, not type ex/ calories, mass, length Intensive properties – depends on type of matter, not amount ex/ density, melting point, boiling point

11. Changes in Matter 1. Physical Change *Changing matter without changing its chemical identity ex/ tear paper, phase change 2. Chemical Change (Chemical reaction) *Changing matter into a new substance *Atoms are rearranged, NOT created ex/ Fe + O 2  Fe 2 O 3

12. Solids -Definite shape -Definite volume, incompressible Liquids -Indefinite shape -Definite volume, slightly compressible Gases -Indefinite shape -Indefinite volume, compressible Physical Change - States of Matter Plasma

13. Physical change – Phase changes Solid  liquid Liquid  gas Gas  liquid Liquid  solid Gas  solid Solid  gas Melting Vaporization Condensation Freezing Deposition Sublimation

15. Chemical Change Chemical reaction – The final substances are chemically different from beginning substances. ◦ Reactants – substances that begin and react ◦ Products – the resulting chemicals

16. Evidence of a Chemical Change 1. Color Change 2. Odor 3. Gas evolved 4. Energy produced 5. Precipitate formation

17. The Periodic Table Arranges elements according to periodic properties Properties depend on location Horizontal rows = periods ◦ There are 7 periods Vertical column = group (or family) ◦ Similar physical & chemical prop. ◦ Identified by number

18. The Periodic Table, cont. Three classes of elements are: 1) Metals: electrical conductors, have luster, ductile, malleable 2) Nonmetals: brittle and non- lustrous, poor conductors of heat and electricity 3) Metalloids: border the line-2 sides Properties are intermediate between metals and nonmetals

19. The Periodic Table

20. The Periodic Table, cont. Group 1A are the alkali metals (but NOT H) Group 2A are the alkaline earth metals H

21. The Periodic Table, cont. Group 8A are the noble gases Group 7A is called the halogens

22. Chapter 1 Review Pg. 22 ~ 1, 3, 6-14, 17, 19-21

23. Observing Matter *Qualitative observation – observation made without measurement *Quantitative observation – observation made through measurement

24. Measuring Matter *Measurement is used to quantify matter *Must be accurate (correct) *Must be precise (repeatable) Neither accurate nor precise Precise, but not accurate Precise AND accurate

25. Measuring Matter, cont. Accurate measurements *Rule: Measure what you know “for sure” plus one estimated digit *2 cm? 2.4 cm? 2.45 cm? *More significant digits = more accuracy 012

26. *The accuracy of your measuring device determines the accuracy of your measurement *How accurate can the above measurement be? Measuring Matter, cont. 0123

27. Which is the most accurate measurement?

28. Significant Figures (Sig Figs) Used to determine the accuracy of a measurement or calculation Standard across all scientific disciplines More sig figs = more accurate

29. Counting Sig Figs – 6 Rules 1. All nonzero digits are significant 425 (3) 24.8 (3) 3.245 (4)

30. Counting Sig Figs – 6 Rules 2. Zeros between nonzero digits are significant 4052 (4) 3.05 (3) 4.001 (4)

31. Counting Sig Figs – 6 Rules 3. Zeros in front of nonzero digits are NOT significant 0.000342 (3) 0.01502 (4)

32. Counting Sig Figs – 6 Rules 4. Zeros on the end AND to the right of the decimal are significant 45.00 (4) 3.0 (2) 0.005200 (4)

33. Counting Sig Figs – 6 Rules 5. Zeros at the end and to the LEFT of the decimal are NOT significant 5000 (1) 4250 (3) 200 (1) **Use scientific notation to show sig figs with these kinds of numbers**

34. Scientific notation *Writes numbers in terms of powers of 10 4.5 X 10 -3  0.0045 3.84 X 10 5  384,000 0.0098  9.8 X 10 -3 25,000  2.5 X 10 4

35. Sig Figs, cont. 6. Unlimited sig figs A. Counted objects B. Defined quantities

36. How many sig figs? 1.0070 m  5 sig figs 17.10 kg  4 sig figs 100,890 L  5 sig figs 3.29 x 10 3 s  3 sig figs 0.0054 cm  2 sig figs 3,200,000 mL  2 sig figs 5 dogs  unlimited These all come from some measurements This is a counted value

37. Calculations and sig figs  In general a calculated answer cannot be more precise than the least precise measurement from which it was calculated.  Ever heard that a chain is only as strong as the weakest link?  Sometimes, calculated values need to be rounded off.

38. Rounding calculations  Rounding  Decide how many significant figures are needed (more on this very soon)  Round to that many digits, counting from the left  Is the next digit less than 5? Drop it.  Next digit 5 or greater? Increase by 1

39. Rounding calculations, cont. 1. Addition and Subtraction The answer should be rounded to the same number of decimal places as the least number of decimal places in the problem ex/ 6.8 + 11.934 = 18.734  18.7 (3 sig figs)

40. Practice… 3.24 m + 7.0 m CalculationCalculator says:Answer 10.24 m 10.2 m 100.0 g - 23.73 g 76.27 g 76.3 g 0.02 cm + 2.371 cm 2.391 cm 2.39 cm 713.1 L - 3.872 L 709.228 L709.2 L 1818.2 lb + 3.37 lb1821.57 lb 1821.6 lb 2.030 mL - 1.870 mL 0.16 mL 0.160 mL *Note the zero that has been added.

41. Rounding calculations, cont. 2. Multiplication and Division Round the answer to the same number of significant figures as the least number of significant figures in the problem. ex/ 6.38 x 2.0 = 12.76  13 (2 sig figs)

42. Practice… 3.24 m x 7.0 m CalculationCalculator says:Answer 22.68 m 2 23 m 2 100.0 g ÷ 23.7 cm 3 4.219409283 g/cm 3 4.22 g/cm 3 0.02 cm x 2.371 cm 0.04742 cm 2 0.05 cm 2 710 m ÷ 3.0 s 236.6666667 m/s240 m/s 1818.2 lb x 3.23 ft5872.786 lb·ft 5870 lb·ft 1.030 g x 2.87 mL 2.9561 g/mL2.96 g/mL

43. Density  The formula for density is: mass volume Common units are: g/mL, or g/cm 3, (or g/L for gas) Density is a physical property, and does not depend upon sample size Density =

44. The Metric System System of base units and prefixes Based on powers of 10 Base units Length – meter (m) Mass – gram (g) Volume – liter (l) *note 1 cm 3 = 1ml water

45. Prefixes Mega M10 6 Kilok10 3 Base unit10 0 Decid10 -1 Centic10 -2 Millim10 -3 Micro  10 -6 Nanon10 -9 Picop10 -12 Move decimal to right Move decimal to left

46. Metric conversions Convert 560 mL to L Convert 4.25 km to mm Convert 2,200 nm to m Convert 0.023 Mg to pg

47. Dimensional Analysis *A method of problem-solving using conversion factors Conversion Factor *Is essentially an equality ex/ 12 inches = 1 foot *Is written as a ratio to cancel units 12 inches OR 1 foot 1 foot12 inches

48. Review- Density & Conversions

49. Dimensional Analysis Problems 1. Convert 15 feet to inches. 2. Convert 176 inches to yards.

50. Dimensional Analysis, cont. 1. Convert 2,500 inches to yards. 2. Convert 0.0034 miles to inches.