1. I II III Units of Measurement Scientific Measurement

2.  August 20 th – 2 nd, 3 rd, 6 th Periods  August 21 st – 6 th, 7 th Periods

3. Number vs. Quantity  Quantity - number + unit UNITS MATTER!!

4. A. Accuracy vs. Precision  Accuracy - how close a measurement is to the accepted value  Precision - how close a series of measurements are to each other ACCURATE = CORRECT PRECISE = CONSISTENT

5. A. Accuracy vs. Precision

6. B. Percent Error  Indicates accuracy of a measurement your value given value

7. B. Percent Error  A student determines the density of a substance to be 1.40 g/mL. Find the % error if the accepted value of the density is 1.36 g/mL.

8. C. Significant Figures  Indicate precision of a measurement.  Recording Sig Figs  Sig figs in a measurement include the known digits plus a final estimated digit 2.31 cm

9. C. Significant Figures  Counting Sig Figs  Digits from 1-9 are always significant  Zeros between two other sig figs are always significant  Zeros at the end of a number are significant when a decimal is present  Count all numbers EXCEPT:  Leading zeros -- 0.0025  Trailing zeros without a decimal point -- 2,500 5085 2.60 739

10. 4. 0.080 3. 5,280 2. 402 1. 23.50 C. Significant Figures Counting Sig Fig Examples 1. 23.50 2. 402 3. 5,280 4. 0.080

11. C. Significant Figures  Calculating with Sig Figs  Multiply/Divide - The # with the fewest sig figs determines the # of sig figs in the answer (13.91g/cm 3 )(23.3cm 3 ) =

12. C. Significant Figures  Calculating with Sig Figs (con’t)  Add/Subtract – Answer can have as many # after the decimal as the # with the least amount of # to the right of the decimal 3.75 mL + 4.1 mL 7.85 mL 3.75 mL + 4.1 mL 7.85 mL

13. C. Significant Figures  Calculating with Sig Figs (con’t)  Exact Numbers do not limit the # of sig figs in the answer  Counting numbers: 12 students  Exact conversions: 1 m = 100 cm  “1” in any conversion: 1 in = 2.54 cm

14. C. Significant Figures 5. (15.30 g) ÷ (6.4 mL) Practice Problems 6. 18.9g - 0.84 g

15.  August 21 st – 2 nd, 3 rd periods  August 22 nd - 5 th, 6 th, 7 th periods

16. D. Scientific Notation  A way to express any number as a number between 1 and 10 (coefficient) multiplied by 10 raised to a power (exponent)  Number of carbon atoms in the Hope diamond  460,000,000,000,000,000,000,000  4.6 x 10 23  Mass of one carbon atom  0.00000000000000000000002 g  2 x 10 -23 g coefficient exponent

17. D. Scientific Notation  Converting into Sci. Notation:  Move decimal until there’s 1 digit to its left. Places moved = exponent  Large # (>1)  positive exponent Small # (<1)  negative exponent  Only include sig figs – all of them! 65,000 kg  6.5 × 10 4 kg

18. D. Scientific Notation 7. 2,400,000  g 8. 0.00256 kg 9. 7.0  10 -5 km 10.6.2  10 4 mm Practice Problems

19. D. Scientific Notation  Calculating with Sci. Notation (5.44 × 10 7 g) ÷ (8.1 × 10 4 mol) = 5.44 EXP EE ÷ ÷ EXP EE ENTER EXE 78.1 4 = 671.6049383= 670 g/mol= 6.7 × 10 2 g/mol Type on your calculator:

20. D. Scientific Notation 11. (4 x 10 2 cm) x (1 x 10 8 cm) 12. (2.1 x 10 -4 kg) x (3.3 x 10 2 kg) 13. (6.25 x 10 2 ) ÷ (5.5 x 10 8 ) 14. (8.15 x 10 4 ) ÷ (4.39 x 10 1 ) 15. (6.02 x 10 23 ) ÷ (1.201 x 10 1 ) Practice Problems

21.  August 26 th - 2 nd, 3 rd, 5 th, 6 th, 7 th periods

22. Temperature Conversions CH. 3 - MEASUREMENT

23. A. Temperature  Temperature  measure of the average KE of the particles in a sample of matter

24.  Convert these temperatures: 1)25 o C = ______________K 2)-15 o F = ______________ K 3)315K = ______________ o C 4)288K = ______________ o F A. Temperature

25. I II III Dimensional Analysis Conversion Factors Problems CH. 3 - MEASUREMENT

26. A. Problem-Solving Steps 1. Analyze 2. Plan 3. Compute 4. Evaluate

27. B. Dimensional Analysis  Dimensional Analysis  A tool often used in science for converting units within a measurement system  Conversion Factor  A numerical factor by which a quantity expressed in one system of units may be converted to another system

28. B. Dimensional Analysis  The “Factor-Label” Method  Units, or “labels” are canceled, or “factored” out

29. B. Dimensional Analysis  Steps to solving problems: 1. Identify starting & ending units. 2. Line up conversion factors so units cancel. 3. Multiply all top numbers & divide by each bottom number. 4. Check units & answer.

30. Fractions in which the numerator and denominator are EQUAL quantities expressed in different units Example: 1 in. = 2.54 cm Factors: 1 in. and 2.54 cm 2.54 cm 1 in. C. Conversion Factors

31. Conversion factor cancel By using dimensional analysis / factor-label method, the UNITS ensure that you have the conversion right side up, and the UNITS are calculated as well as the numbers! How many minutes are in 2.5 hours? 2.5 hr 1 x xx x 60 min 1 hr = 150 min

32. Write conversion factors that relate each of the following pairs of units: 1. Liters and mL 2. Hours and minutes 3. Meters and kilometers C. Conversion Factors Learning Check:

33. D. SI Prefix Conversions 1.Memorize the following chart. (next slide) 2.Find the conversion factor(s). 3.Insert the conversion factor(s) to get to the correct units. 4.When converting to or from a base unit, there will only be one step. To convert to or from any other units, there will be two steps.

34. mega-M10 6 deci-d10 -1 centi-c10 -2 milli-m10 -3 PrefixSymbolFactor micro-  10 -6 nano-n10 -9 kilo-k10 3 BASE UNIT---10 0 giga-G10 9 deka-da10 1 hecto-h10 2 tera-T10 12 move left move right A. SI Prefix Conversions pico-p10 -12

35. D. SI Prefix Conversions 1 T(base) = 1 000 000 000 000(base) = 10 12 (base) 1 G(base) = 1 000 000 000 (base) = 10 9 (base) 1 M(base) = 1 000 000 (base) = 10 6 (base) 1 k(base) = 1 000 (base) = 10 3 (base) 1 h(base) = 100 (base) = 10 2 (base) 1 da(base) = 10 1 (base) 1 (base) = 1 (base) 10 d(base) = 1(base) 100 c(base) = 1 (base) 1000 m (base) = 1(base) 1 (base) = 1 000 000 µ = 10 -6 (base) 1 (base) = 1 000 000 000 n = 10 -9 (base) 1 (base) = 1 000 000 000 000 p = 10 -12 (base) Tera- Giga- Mega- Kilo- Hecto- Deka- Base Deci- Centi- Milli- Micro- Nano- Pico-

36. a. cm to m b. m to µm c. ns to s d. kg to g D. SI Prefix Conversions

37. 1) 20 cm = ______________ m 2) 0.032 L = ______________ mL 3) 45  m = ______________ m

38. 4) 805 Tb = ______________ b Terabytes bytes D. SI Prefix Conversions

39. 1) 400.  g = ______________ kg 1) 57 Mm = ______________ nm D. SI Prefix Conversions

40.  You have $7.25 in your pocket in quarters. How many quarters do you have? X E. Dimensional Analysis Practice 7.25 dollars 1 1 dollar 4 quarters

41. How many seconds are in 1.4 days? = 12000 s E. Dimensional Analysis Practice 1.4 days 24 hr60 min 60 s 1 day 1 hr1 min

42. E. Dimensional Analysis Practice  How many milliliters are in 1.00 quart of milk?

43.  You have 1.5 pounds of gold. Find its volume in cm 3 if the density of gold is 19.3 g/cm 3. E. Dimensional Analysis Practice

44. 5) Your European hairdresser wants to cut your hair 8.0 cm shorter. How many inches will he be cutting off? E. Dimensional Analysis Practice

45. 6) Roswell football needs 550 cm for a 1st down. How many yards is this? E. Dimensional Analysis Practice

46. 7) A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire? E. Dimensional Analysis Practice

47.  How many liters of water would fill a container that measures 75.0 in 3 ? E. Dimensional Analysis Practice