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Chapters 1 & 2: Learning Targets

Chapters 1 & 2: Learning Targets. Identify a given substance as an element or compound Classify properties and changes as chemical or physical Explain the structure of the periodic including properties of elements based on their location (metal, nonmetal, etc.)

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Chapters 1 & 2: Learning Targets

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  1. Chapters 1 & 2: Learning Targets • Identify a given substance as an element or compound • Classify properties and changes as chemical or physical • Explain the structure of the periodic including properties of elements based on their location (metal, nonmetal, etc.) • Determine the amount of heat transferred in a process • Express data and results of calculations with appropriate significant figures, units, and in scientific notation • Calculate percent error from lab data and use this to evaluate the quality of lab data • Perform density calculations and apply density conceptually (e.g. identifying substances or determining if an object will float

  2. Chapters 1 & 2: Key Words • Atom • Compound • Element • Pure substance • Mixture • Homogeneous • Heterogeneous • Chemical change/property • Physical change/property • Direct/inverse proportion • Family/group • Significant figure • Scientific notation • Conversion factor • Percent error • Metal • Nonmetal • Metalloid • Noble gas • Quantitative • Qualitative • Period

  3. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 • Scientific notation is a way of taking very large numbers and/or very small numbers and writing them more simply • For example, an important number in chemistry is 602,000,000,000,000,000,000,000which sucks to write…but in scientific notation it is6.02 x 1023

  4. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 • Use the examples below to come up with a set of rules for converting from scientific to regular notation __________________________________________________________ __________________________________________________________ __________________________________________________________

  5. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 • Use the examples below to come up with a set of rules for converting from regular to scientific notation __________________________________________________________ __________________________________________________________ __________________________________________________________

  6. Write 8,240,000 in scientific notation. • 8.24 • 8.24 x 10-6 • 8.24 x 106 • 8,240,000

  7. Write 3.5 x 10-3 in regular notation. • 3.5 • .0035 • 3500 • 35000

  8. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 • Measurements made in the lab are never perfect, or they all have some uncertainty • Measurements contain all numbers we are sure of –certain digits – and one estimated digit – an uncertaindigit • The certain digits and the oneuncertain digit together are thesignificant figures

  9. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 • Significant figures also indicates a measuring device’s accuracy

  10. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 • The numbers gathered in the lab will be used to calculate results; these results must accurately indicate the uncertainty of the data • The first step with this is to look at an individual number and determine the number significant figures it contains • For example, you should be able to look at a number such as 224.6 and determine the number of significant figures it contains • From that point, rules exist for calculations, as will be seen

  11. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 When are nonzero numbers significant? (circle one) Always Sometimes Never When are leading zeros significant? (circle one) Always Sometimes Never When are captive zeros significant? (circle one) Always Sometimes Never When are trailing zeros significant? (circle one) Always Sometimes Never

  12. How many significant figures are in the number below? 4503 • 0 • 1 • 2 • 3 • 4 • 5

  13. How many significant figures are in the number below? 0.002 • 0 • 1 • 2 • 3 • 4 • 5

  14. How many significant figures are in the number below? 2050 • 0 • 1 • 2 • 3 • 4 • 5

  15. How many significant figures are in the number below? 170.0 • 0 • 1 • 2 • 3 • 4 • 5

  16. How many significant figures are in the number below? 0.02050 • 0 • 1 • 2 • 3 • 4 • 5

  17. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 • The answer reported after calculations have been performed from data must have the correct number of significant figures • There is one rule that applies to calculations involving multiplication and division • There is a second rule that applies to calculations involving addition and subtraction • In questions that involve multiple math operations, the order of operations must be employed

  18. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 2.0 x 4 = 8 2.44 x 8.629 = 21.1 9.166 x 3.2 = 29 199.2 ÷ 4.05 = 49.2 2.66543 x 0.0032 = .0085 0.026 x 0.00449 = .00012 0.02 ÷ 0.00606894 = 3 (5.4 x 102)(6.39 x 10-6) = 3.5 x 10-3 Determine the number of significant figures in each answer above. Determine the number of significant figures in each number in the question above. How is the number of significant figures in the answer determined in a question involving multiplication or division? (Write in the space below)

  19. Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46 8.663 – 2.1 = 6.6 14.2 + 2 = 16 1.00036 + 0.2 = 1.2 9.887467 2.003 = 7.884 8.3654345343 + 1 = 9 6.22 + 2.1 = 8.3 68.633 + 7.9343 = 76.567 4.0 + 12.98373 = 17.0 Determine the number of significant figures in each answer above. Determine the number of significant figures in each number in the question above. How is the number of significant figures in the answer determined in a question involving addition or subtraction? (Write in the space below)

  20. Solve the following with correct sig figs.4.56 x 1.4 = ? • 6.384 • 6.38 • 6.3 • 6.4 • 6

  21. Solve the following with correct sig figs.4.56 - 1.4 = ? • 3.16 • 3.2 • 3.1 • 3.160 • 3

  22. Solve the following with correct sig figs.4.184 x 100.62 x (25.27-24.16) = ? • 470 • 467.3 • 467.30 • 460 • 467

  23. Solve the following with correct sig figs.(6.0 x 1023)(4.22) = ? • 2.532 x 1024 • 2.5 x 1024 • 2.53 x 1024 • 3 x 1024 • 2.5320 x 1024

  24. Solve the following with correct sig figs.[(2.853 x 107) –(1.200 x 103)] x 2.8954 = ? • 8 x 107 • 8.3 x 107 • 8.26 x 107 • 8.260 x 107 • 8.2602 x 107

  25. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • A key skill in chemistry is being able to take a given quantity with a certain unit and convert it to an equal quantity with a different unit • For example, being able to determine the number of inches in five feet • Both of these quantities represent the same distance, but express the distances with different numbers and units • The key to using dimensional analysis is the correct use of conversion factors

  26. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • The techniques used to apply conversion factors are the same as those used when multiplying fractions:

  27. What is the product of 3 and 2/3? • 2 • 3 • 1/2 • 3/2 • 6

  28. What is the product of 3/4 and 2/3? • 3 • 4 • 2/3 • 3 • 1/2

  29. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • In each case, a common numerator and denominator cancel • This idea is the key to using conversion factors; the difference is, with conversion factors, you select the fraction to get the result you need, and the focus is on units, not numbers • For example, to convert pounds to grams: pounds x ----------------- = grams

  30. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • Set up the appropriate conversion factor for the following: a) inches to centimeters b) miles per hour to meters per minute

  31. Which is the correct conversion factor for converting feet to inches?

  32. Which conversion factors are properly arranged to convert feet per second to inches per minute?

  33. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • Once the units are properly arranged, the numerical relationship between the units in the conversion factor must be considered • For example, to convert feet to inches, it must be known that there are 12 inches in 1 foot • After the units are arranged, the number is placed with its unit; that is, wherever “inches” was placed in the conversion factor, write 12 next to it Potentially Useful Information 1 ft3 = 28.32 L 1 mi = 1.609 km 1 in3 = 16.38 cm31 in = 2.54 cm 1 kg = 2.2 lbs 1 oz = 28.35 g 1 lb = 16 oz 1 gallon = 3.785 L 1 lb = 453.59 g 1 ft = 12 in 1 ft3 = 1728 in33 ft = 1 yd 1 m = 3.281 ft 1 mi = 5280 ft 1 cal = 4.184 J

  34. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • In terms of significant figures, the numbers in a conversion numbers are considered to be exact numbers • Exact numbers are assumed to have an infinite number of significant figures; if they have infinite sig figs, there is no way they can have the fewest number of sig figs in the question • Therefore the numbers in the conversion factor will never be used to determine the significant figures in the answer

  35. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • Use conversion factors and show all work to solve the following. • How many inches are there in 2.0 feet? • Convert 12 miles per hour to meters per minute.

  36. What mass in grams is equal to 10.0 pounds? • .022 g • 4540 g • 45.359 g • 22 g

  37. What speed, in meters per minute, is equivalent to 20.0 feet per second? • 3930 m/min • .101 m/min • 1.09 m/min • 366 m/min

  38. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • Units with the word “per” in them are a special kind of fun: miles per hour – mi/hr meters per second – m/s grams per mole – g/mol grams per liter – g/L • FUN FACT #1: These units are found by dividing the two quantities involved Miles per hour = miles ÷ hours

  39. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • FUN FACT #2: A quantity whose unit contains the word “per” is a conversion factor! • For example, a speed with the unit of miles per hour (mi/hr) gives the number of miles driven in 1 hour • So a speed of 25 mi/hr (miles per hour) means 25 miles for every 1 hour or…. 25 miles = 1 hour

  40. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 If you drive for 4.0 hours at a speed of 25 mi/hr, how many mile will you drive?

  41. A metal has a density of 17.4 g/mL. What volume, in mL, of space will 11.1 g of this metal occupy? • 17.4 mL • 11.1 mL • .638 mL • 1.57 mL

  42. Molar mass has a unit of grams per mole. If 3.55 moles has a mass of 79.2 grams, what is the molar mass? • .0448 g/mol • 22.3 g/mol • 3.55 g/mol • 281 g/mol

  43. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • Metric conversions (mL to L, g to kg) can be performed without the use of conversion factors • These conversions are performed by moving the decimal point to the correct location as determined by the metric prefixes used

  44. Section 2: Dimensional AnalysisPages 40-42 RBQs Pgs. 60-61 #28-32, 49 • How many milliliters are there in 75 deciliters? • How many centimeters are there in 0.255 decameters?

  45. How many kilometers are there in 8,230 mm? • 82,300 km • .00823 km • .0823 km • .823 km • 82.3 km

  46. How many meters are there in 50 cm? • 50 m • 5000 m • 500 m • .05 m • 0.5 m

  47. How many mg are in 46 g? • 46000 mg • 4600 mg • 460 mg • 4.6 mg • .046 mg

  48. Section 3: Units, Density, and Percent ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50 • Data or information can be either qualitative or quantitative Quantitative: Qualitative:

  49. Section 3: Units, Density, and Percent ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50 • These base units are then modified to with metric prefixes to give more appropriate numbers

  50. Section 3: Units, Density, and Percent ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50 • The base units can be combined to give derived units; volume is one example 1. What formula/equation would be used to find a cube’s volume? 2. What units would be used when measuring each of the cubes dimension? 3. Therefore, what are possible units for volume?

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