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Chapter 1 and 2

Chapter 1 and 2. Introduction to Chemistry. Quantitative vs Qualitative. Quantitative Measurements Ex. 23 m, :46 s, 3.5 kg Qualitative Observations Deals with senses Ex. Yellow, bitter, loud. Graphs and Charts – Pie Charts. % or part of a whole. Graphs and Charts – Bar Graph.

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Chapter 1 and 2

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  1. Chapter 1 and 2 Introduction to Chemistry

  2. Quantitative vs Qualitative • Quantitative • Measurements • Ex. 23 m, :46 s, 3.5 kg • Qualitative • Observations • Deals with senses • Ex. Yellow, bitter, loud

  3. Graphs and Charts – Pie Charts • % or part of a whole

  4. Graphs and Charts – Bar Graph • Quantity over varied locations

  5. Graphs and Charts – Line Graph • Shows a relationship or trend of data • Variable on the x-axis is the independent variable • Variable on the y-axis is the dependent variable

  6. Graphs and Charts – Line Graph • Line of best fit • The line follows the overall movement of points • Use a straight edge

  7. 5 minutes • Work on vocabulary for chapter 2

  8. Theories and Laws • Do theories become laws? • Is a theory like a hypothesis?

  9. Theories and Laws • Theory – A true statement based upon facts and data that we have now. • Ex. Theory of Evolution • Can a theory change? • Yes, theories can be modified when we get additional data or observations. • Law – based on observable fact. • Theories can be used to explain laws. • Does not change. • Ex. Law of gravity

  10. Pure Research vs Applied Research • Pure research • Purely for gaining knowledge • Applied research • Uses knowledge to solve a problem • Ex. A chemist and a chemical engineer

  11. SI Unit • Standard International Unit • How is it different from units that we use like feet or pounds? • Why is it important? • Digits 0-10 • Place 1-10-100-1000… • Ex. 12 • I have 1 group of 10 and 2 groups of 1

  12. 2 Types of Units • Base • Defined unit of measurement • Time (s), length(m), and mass (kg) • Derived • What does derived mean? • Comes from a combination of base units • Mph, g/ml, g/cm3

  13. SI Base Units • Time – s • Length – m • Mass - kg

  14. Density – A Derived Unit • What is the formula for density? • D = m/v • Ex. 5.2 g occupy 15.6 mL • 5.2 g / 15.6 ml = .333 g /mL

  15. Units of Measurement • 231 • What does this mean? • 231 lbs, 231 cm, 231 g • Unit of measurement is important. • Make sure you include this.

  16. Pg. 26 • 10 -2 = centi • We will not use negative exponents for this • 1 m = 102cm

  17. 1 Mm = 106m • 1km = 103m • 1 m = 10 dm • 1 m = 102 cm • 1m= 103mm • 1m = 106 µm • 1 m = 109nm • 1m = 1012pm • 1 ML = 106L • 1kL = 103L • 1 L = 10 dL • 1 L = 102cL • 1L= 103mL • 1L = 106 µL • 1 L = 109nL • 1L = 1012pL

  18. Mass Conversions • You should see the relationship among the prefixes.

  19. Test Taking Strategy • Write down prefixes with conversions somewhere on the test.

  20. 1 mL = 1 cm3

  21. Conversion problems • Pg.34

  22. Temperature • What does temperature actually measure? • Heat or amount of energy • We will use Celsius and Kelvin • What temperature does water freeze and boil? • Can you go below 00C? • Liquid nitrogen is -1960C • Dry ice is -78.50C • Can liquid water ever go above 1000C?

  23. The Kelvin Scale • What is freezing point of water on the Kelvin scale? • 273 K • What is 0 K? • Absolute 0 • This is as cold as it gets

  24. Scientific Notation • N x 10n What part is the number? • All of it • 1 < m < 10 Precision • 0.23451 is more precise than 0.2 • N (integer) Magnitude (exponent) • The greater the exponent the larger the magnitude • +N (exponent) Larger • -N (exponent) Smaller

  25. Scientific Notation • 4231.3 • 4.2313 x 103 • 0.002179 • 2.179 x 10 -3 • 0.012 x 10-1 • 1.2 x 10-3 • 300 x 102 • 3 x 104 • 1000 x 10-2 • 1 x 10 • The number you end with must have the same value as the number you start with.

  26. Scientific Notation Problems • Pg. 32

  27. Data Analysis • Interpolating Data • Data that comes from points on the line • Between extreme measured points • Extrapolating Data • Uses the trend of a line to make a prediction • Does not come from measured points

  28. Accuracy vs Precision • Accuracy • Closeness to accepted value • Precision • Reproducing a given measurement

  29. Percent Error

  30. Percent Error Problems • Pg. 38

  31. Calculator • Texas Instrument • Programmable (Graphing)

  32. Assign Calculators and Rules • You will get your calculator everyday unless I tell you otherwise. • Put your calculator number in your book by your name. • Calculators are around $100.00. • Do not use anything other than you fingers to touch the calculator. No pens or pencils. • Do not pick on the black rubber pieces on the back of the calculator. • Do not mess with the batteries or the battery door. • I need to know if your number is missing.

  33. Homework • Page 50 • 72-75, 80, 82, 86

  34. Homework Review

  35. Significant Digits • Do this on your calculator. • 2300 + 1200 • What do you get? Are all of these numbers significant?

  36. Significant Digit Rules • Non zero digits are significant • Embedded zeros are significant • What does embedded mean? • Placeholding zeros are not significant • Trailing zeros to the right of an explicit decimal are significant. • What is an explicit decimal? What is an implied decimal? • Counting numbers and constants never determine significance.

  37. Significant Digit Rules Ex. • Rule 1: All non zero digits are significant. • How many significant digits are in: • 42.14 • 92.35 • 2.1497421

  38. Significant Digit Rules Ex. • Rule 2: Embedded zeros are significant. • How many significant digits are in: • 2.1505 • 304210.401 • 42.000005

  39. Significant Digit Rules Ex. • Rule 3: Placeholding zeros are never significant. • How many significant digits are in: • 3100 • 40 • 0.00032485

  40. Significant Digit Rules Ex. • Rule 4:Trailing zeros to the right of an explicit decimal are significant. • 560 and 560.0 • What’s the difference? • 560 can be in the range of 555-564 • 560.0 can be in the range of 559.95-560.04

  41. Rule 4 continued • How many significant digits are in: • 0.0500 • 400.0 • 10000.0 • 0.000540

  42. Significant Digit Rules Ex. • Rule 5: Counting numbers and constants will never determine significance. • Avogadro’s constant - 6.023x1023 • 6 molecules • Numbers such as these would not be used to calculate the number of significant digits in your answer.

  43. Calculations Using Significant Digits • In your calculations you will use the least amount of significant digits for multiplication and division. • In the problem 3829 x 8100, what is the least amount of significant digits? • That is the one you will use in your answer. • For addition and subtraction, you will round to the least place. • 34.56 + 9.2, what is the least place? • That is the place you will use in your answer

  44. Addition and Subtraction • 3.215 + 2.5 • 410 + 321.5721 • 821 – 1.7623

  45. Multiply and Divide • 4.213 x 1.5 • 6.72 x 3.3419 • 3.75 / 1.223

  46. Significant Digits Practice • Give the number of significant digits for the following. • 401.2 • 300 • 50421.001 • 0.0200 • 3.1 x 10-2 • 3.0023 x 105 • 5.7010 x 1012

  47. Understand? • If you grasp the idea of significant digits then answer this. • Write 100 with 2 significant digits.

  48. Entering Exponents into Your Calculator • 2.4315 x 102 • You will enter 2.4315 then EE 2 • Your answers will also show up in this format

  49. Dimensional Analysis / Unit Conversion / Factor Label • When adding and subtracting the units will remain the same. • When multiplying the units will become squared. • When dividing the units will cancel. • You will always round to significant digits but the magnitude must remain the same. • Your answer is 4800 and must have 2 significant digits. • You would not put 4.8. The answer would be 4.8 x 103

  50. Rules for Exponents • Xn x Xm = Xn+m • Xn / Xm = Xn-m • (Xn)m = Xn x m • 1 / Xn = X-n

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