1. I. Using Measurements MEASUREMENT IN SCIENCE

2. 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 Accuracy - how close a measurement is to the accepted value Precision - how close a series of measurements are to each other ACCURATE = CORRECT PRECISE = REPEATABLE

3. B. Percent Error Indicates accuracy of a measurement your value accepted value

4. 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. % error = 2.9 %

5. 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 Indicate precision of a measurement. Recording Sig Figs Sig figs in a measurement include the known digits plus a final estimated digit 2.35 cm

6. C. Significant Figures Counting Sig Figs Count all digits (1-9) Zero Rules: Trapped zeros -- 101 are always significant Preceding zeros -- 0.0025 are never significant Trailing zeros -- 2500 only with a decimal point Counting Sig Figs Count all digits (1-9) Zero Rules: Trapped zeros -- 101 are always significant Preceding zeros -- 0.0025 are never significant Trailing zeros -- 2500 only with a decimal point

7. 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 4 sig figs 3 sig figs 2 sig figs

8. C. Significant Figures Calculating with Sig Figs Multiply/Divide - The # with the fewest sig figs determines the # of sig figs in the answer. 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 ) = 324.103g 324 g 4 SF3 SF

9. C. Significant Figures Calculating with Sig Figs (con’t) Add/Subtract - The # with the lowest decimal value determines the place of the last sig fig in the answer. Calculating with Sig Figs (con’t) Add/Subtract - The # with the lowest decimal value determines the place of the last sig fig in the answer. 3.75 mL + 4.1 mL 7.85 mL 224 g + 130 g 354 g  7.9 mL  350 g 3.75 mL + 4.1 mL 7.85 mL 224 g + 130 g 354 g

10. 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 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

11. C. Significant Figures 5. (15.30 g) ÷ (6.4 mL) Practice Problems = 2.390625 g/mL  18.1 g 6. 18.9g - 0.84 g 18.06 g 4 SF 2 SF  2.4 g/mL 2 SF

12. D. Scientific Notation Converting into Sci. Notation: Move decimal until there’s 1 digit to its left. Places moved = exponent. Large # (>1) Þ positive exponent (left) Small # (<1) Þ negative exponent (right) Only include sig figs. Converting into Sci. Notation: Move decimal until there’s 1 digit to its left. Places moved = exponent. Large # (>1) Þ positive exponent (left) Small # (<1) Þ negative exponent (right) Only include sig figs. 65,000 kg  6.5 × 10 4 kg

13. D. Scientific Notation 7. 2,400,000  g 8. 0.00256 kg 9.7  10 -5 km 10.6.2  10 4 mm 7. 2,400,000  g 8. 0.00256 kg 9.7  10 -5 km 10.6.2  10 4 mm Practice Problems 2.4  10 6  g 2.56  10 -3 kg 0.00007 km 62,000 mm

14. 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 7 8.1 4 = 671.6049383 = 670 g/mol = 6.7 × 10 2 g/mol Type on your calculator:

15. II. Units of Measurement MEASUREMENT

16. A. Number vs. Quantity Quantity - number + unit UNITS MATTER!!

17. B. SI Units QuantityBase UnitUnit Abbrev. Length Mass Time Temp meter kilogram second kelvin m kg s K Amountmolemol Variable Symbol l m t T n

18. B. SI Units mega-M10 6 deci-d10 -1 centi-c10 -2 milli-m10 -3 PrefixSymbolFactor micro-  10 -6 nano-n10 -9 pico-p10 -12 kilo-k10 3 BASE UNIT---10 0

19. C. Derived Units Combination of base units. Volume (m3 or cm3) length x length x length Combination of base units. Volume (m3 or cm3) length x length x length 1 cm 3 = 1 mL 1 dm 3 = 1 L

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

21. III. Unit Conversions (Dimensional Analysis) III. Unit Conversions (Dimensional Analysis) MEASUREMENT

22. A. SI Prefix Conversions 1.Find the difference between the exponents of the two prefixes. 2.Move the decimal that many places. 1.Find the difference between the exponents of the two prefixes. 2.Move the decimal that many places. To the left or right?

23. = A. SI Prefix Conversions NUMBER UNIT NUMBER UNIT 532 m = _______ km 0.532

24. A. SI Prefix Conversions mega- M10 6 deci- d10 -1 centi- c10 -2 milli- m10 -3 PrefixSymbolFactor micro-  10 -6 nano- n10 -9 pico-p 10 -12 kilo- k10 3 move left move right BASE UNIT ---10 0

25. A. SI Prefix Conversions 1) 20 cm = ______________ m 2) 0.032 L = ______________ mL 3) 45  m = ______________ nm 4) 805 dm = ______________ km 1) 20 cm = ______________ m 2) 0.032 L = ______________ mL 3) 45  m = ______________ nm 4) 805 dm = ______________ km 0.2 0.0805 45,000 32

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

30. B. Dimensional Analysis Steps: 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. Steps: 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.

31. B. Dimensional Analysis Lining up conversion factors: 1 in = 2.54 cm 2.54 cm 1 in = 2.54 cm 1 in 1 in = 1 1 =

32. B. Dimensional Analysis How many milliliters are in 1.00 quart of milk? 1.00 qt 1 L 1.057 qt = 946 mL qtmL 1000 mL 1 L

33. B. Dimensional Analysis You have 1.5 pounds of gold. Find its volume in cm 3 if the density of gold is 19.3 g/cm 3. lbcm 3 1.5 lb 1 kg 2.2 lb = 35 cm 3 1000 g 1 kg 1 cm 3 19.3 g

34. B. Dimensional Analysis How many liters of water would fill a container that measures 75.0 in 3 ? 75.0 in 3 (2.54 cm ) 3 (1 in ) 3 = 1.23 L in 3 L 1 L 1000 cm 3

35. B. Dimensional Analysis 5) Your European hairdresser wants to cut your hair 8.0 cm shorter. How many inches will he be cutting off? 8.0 cm 1 in 2.54 cm = 3.2 in cmin

36. B. Dimensional Analysis 6) WF football needs 550 cm for a 1st down. How many yards is this? 6) WF football needs 550 cm for a 1st down. How many yards is this? 550 cm 1 in 2.54 cm = 6.0 yd cmyd 1 ft 12 in 1 yd 3 ft

37. B. Dimensional Analysis 7) A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire? 7) A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire? 1.3 m 100 cm 1 m = 86 pieces cmpieces 1 piece 1.5 cm