1. Used to communicate the accuracy of measurements
Significant Figures
Used to communicate the accuracy of measurements
9/9/14 start here 1st period.

2. When is a digit significant?
The digits 1 through 9 are always significant
Zeros may or may not be significant

3. How do I determine significant figures
We will use a method called Atlantic- Pacific to determine the number of significant figures.

4. Using Atlantic-Pacific Method
Is there a decimal?
No: count from the Atlantic side of the number starting with first non-zero number
How many significant figures in 9500?
9500 2

5. More Practice
How many significant figures in
100
607100
8008

6. Using Atlantic-Pacific Method
Is there a decimal?
Yes: count from the Pacific side of the number starting with first non-zero number
How many significant figures in ? 2

7. More Practice How many significant figures in 0.2100 0.000910 5.2030
900.

8. Assignment
Complete page 2 of Math Guided Practice.

9. Math Guided Practice p.2
100.0
100
100.00
1,002
0.011
1.02
0.180
110.00
140,000,000
1.00 x 1024
x 1013
1.08 x 105
950
0.850
129
0.198
4050
980890
3.005
.0100 10
580
580.
0.0058

10. Scientific Notation 1235060 1.23506 x 105 1.23506 x 10x
Move decimal point so there is one non- zero digit to the left of the decimal point. Remember to include only significant figures when you rewrite number with a decimal place.
Count the number of places the decimal point was moved. This becomes the power for the 10x. Since is greater than 1 the power will be positive.

11. Scientific Notation
used to make both really big and small numbers easier to work with.
Numbers greater than one will have positive exponent
Numbers less than one will have negative exponent
Preserve the number of significant figures

12. Scientific Notation Practice
123615
1200
1520.
695

13. Scientific Notation Practice
0.3100

14. Scientific Notation to Standard Notation
1.276 x 105 =
1.290 x 10-3 =
127600

15. Math Guided Practice p.1 1) 0.0050 __________ 2) 16000 __________
3) __________
4) __________
5) __________
6) __________
7) __________
8) __________
9) __________
10) __________
4th Period Start here on 9/10. Students finished as homework. Take to fire alarm and fume hood.
6th Start here on 9/10

16. Math Guided Practice p.1 11) 1 x 108 __________

17. Entering Scientific Notation in a Calculator
Type in the number
Press the EE or EXP key
Type in the exponent. Remember to add the “-” if the exponent is negative.
Use the EE or EXP key only!
Start here 1st period on 9/10

18. Scientific Notation 21) (3 x 108) / (2.5 x 108) __________
25) (1 x 108) x (2.00 x 108) __________
26) (4.6 x 108) x (2 x 107) __________
27) (1 x 108) x (2 x 109) __________
28) (1.5 x 1017) x (3 x 1010) _________
15.5 or 1.55 x 101
0.15 or 1.5 x 10-1
2.5 x 10-11
2 x 1016
9.2 x 1015
2 x 1017
4.5 x 1027

19. Mathematical Operation with Significant Figures p
Mathematical Operation with Significant Figures p. 3 Math Guided Practice
An answer cannot be more accurate than the least accurate measurement in the operation

20. Addition and Subtraction with Significant Figures=
6.5
When adding or subtracting numbers, count the NUMBER OF DECIMAL PLACES to determine the number of significant figures. The answer cannot CONTAIN MORE PLACES AFTER THE DECIMAL POINT THAN THE SMALLEST NUMBER OF DECIMAL PLACES in the numbers being added or subtracted.

21. Addition and Subtraction with Significant Figures
4.85
1) ___________ 2) ___________ 3) ______________ 4) ___________ 5) __________
200.1 11
7.21
104

22. Addition and Subtraction with Significant Figures
6) _____________ 7) ______________ 8) ____________ 9) _________ 10) ________
7.14
2.0
202.2
0.008
0.430

23. Multiplication and Division with Significant Figures
3.2 x 1.21 x =
When multiplying or dividing numbers, count the NUMBER OF SIGNIFICANT FIGURES for each number. The answer must be rounded to the smallest number of significant figures.

24. Multiplication and Division with Significant Figures
1) 1.58 x __________
2) 2 x 3.14 _____________
3) x .145 __________
4) x 15 _____________
5) x 0.02 __________
3.17 6
1.2 x 106
9 x 10-4
Start 3rd om 9/11

25. Multiplication and Division with Significant Figures
6) 12.6 / 6 __________
7) / __________
8) / 10 __________
9) / 4.56 __________
10) 0.01 / __________ 2
2 x 103 1
5.54
0.007

26. MSDS Material Safety Data Sheet

27. MSDS Read GPS 2 Resource Notes p. 3 on Material Safety Data Sheets.
Complete CH-1b MSDS Scavenger Hunt using the MSDS documents on your table.

28. NFPA Labels

29. Taking Measurements GPS 2 Resource Notes pp. 3-4
When taking measurements:
Read to the smallest mark on the instrument
Estimate one digit past the smallest mark

30. Measuring Volume
Determine the volume contained in a graduated cylinder by reading the bottom of the meniscus at eye level.
Read the volume using all certain digits and one uncertain digit.
Certain digits are determined from the calibration marks on the cylinder.
The uncertain digit (the last digit of the reading) is estimated.

31. Reading the Graduated Cylinder
Liquids in glass and some plastic containers curve at the edges
Changing the diameter of the cylinder will change the shape of the curve
This curve is called the MENISCUS

32. Reading the Graduated Cylinder
Your eye should be level with the top of the liquid
You should read to the bottom of the MENISCUS

33. Use the graduations to find all certain digits
There are two unlabeled graduations below the meniscus, and each graduation represents 1 mL, so the certain digits of the reading are…
52 mL.

34. Estimate the uncertain digit and take a reading
The meniscus is about eight tenths of the way to the next graduation, so the final digit in the reading is
0.8 mL
The volume in the graduated cylinder is
52.8 mL.

35. Reading a graduated cylinder GPS 2 Resource Notes p. 9
All of the equipment below measures volume in mL but the scales for each are different.
7.5mL
16.5mL
3.80mL

36. 6.62mL 10 mL Graduated Cylinder
What is the volume of liquid in the graduate?
6.62mL

37. 11.5 mL 25mL graduated cylinder
What is the volume of liquid in the graduate?
11.5 mL

38. 100mL graduated cylinder 52.7mL
What is the volume of liquid in the graduate?
52.7mL

39. Practice Reading the Graduated Cylinder
What is this reading?
61.2 ml

40. Practice Reading the Graduated Cylinder
What is this reading?
42.9 ml

41. Measuring Liquid Volume
What is the volume of water in each cylinder?
Images created at A B C
Pay attention to the scales for each cylinder.

42. What is the volume in the buret?

43. What is the volume in the buret?

44. The Thermometer
Determine the temperature by reading the scale on the thermometer at eye level.
Read the temperature by using all certain digits and one uncertain digit.
Certain digits are determined from the calibration marks on the thermometer.
The uncertain digit (the last digit of the reading) is estimated.
On most thermometers encountered in a general chemistry lab, the tenths place is the uncertain digit.

45. Do not allow the tip to touch the walls or the bottom of the flask.
If the thermometer bulb touches the flask, the temperature of the glass will be measured instead of the temperature of the solution. Readings may be incorrect, particularly if the flask is on a hotplate or in an ice bath.

46. Reading the Thermometer
Determine the readings as shown below on Celsius thermometers:
_ _ . _ C 8 7 4
_ _ . _ C 3 5

47. Measuring Solid Volume
Math Guided Practice p. 6
We can measure the volume of regular object using the formula length x width x height.
10 cm
9 cm
8 cm
_____ X _____ X _____ = _____

48. Measuring Solid Volume
Math Guided Practice p. 6
We can measure the volume of irregular object using water displacement.
Amount of H2O with object = ______ Amount of H2O without object = ______ Difference = Volume = ______

49. Practice Reading the Graduated Cylinder
What is this volume?
47.0 ml

50. Online Practice
Reading a graduated cylinder a_meniscus.swf
Reading a buret wf
Reading a ruler a_ruler.swf

51. Homework Complete p. 3 in Math Guided Practice
Complete Measuring Practice
Complete p. 6 Volume in Math Guided Practice
Separation Techniques Practice
Start here with 7th on 9/11

52. Experimental Design GPS 2 Resource Notes p. 5
Dependent Variable(s)
This is the response that you are measuring
Independent Variable(s)
These are the ones you are controlling or manipulating

53. Experimental Design Control This is what you use as a comparison.
Constants
Constants do not change throughout the experiment.

54. Experimental Design Example:
A student is determining the rate at which a certain substance evaporates by checking the volume every 60 minutes.
I.V. = time (minutes)
D.V. = volume

55. Experimental Design Example:
A balloon full of air is heated slowly to observe its change in volume.
I.V. = temperature
D.V. = volume

56. Parts of the Experiment Practice What is the I.V., D.V. and Control?
Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.

57. Observations GPS 2 Resource Notes p. 5
Qualitative
Descriptive data such as color, texture, relative size, or shape.
Quantitative
Numberical data such as mass, volume, or pH.

58. Accuracy vs Precision GPS 2 Resource Notes p. 5
Describes how close an experimental determined value is compared to the known or true value.
Precision
Describes how close the experimental trials are to each other.

59. Accuracy vs Precision Practice Accurate, Precise, Both, or Neither?
78.1mL, 43.9mL, 2mL

60. Percent Error GPS 2 Resource Notes p.6 Math Guided Practice p. 5
|Experimental Value – Theoretical Value| x 100
Theoretical Value
A student measured the string as 1.25m long. The teacher said it was actually 2.12m long. What was the student’s percent error?

61. Graphing Data Trial Temp. Volume 1 25 101.2 2 30 102.1 3 35 103.2 4 40
105.0 5 45
106.5 6 50
108.4 7 55
110.1 8 60
111.3 9 65
112.8 10 70
114.0

62. Sources of Error Are you missing steps in your procedure?
Procedural error
Are you missing steps in your procedure?
Are steps of your procedure making incorrect assumptions?
Are you incorrectly measuring your product/result?
Systematic error
Consistently causes measurements to be too high or too low (a systematic error will always throw off you measurements by the same amount and in the same direction)
Ex: a balance is not properly zeroed or an instrument is not properly calibrated
Random error
A source of measurement error due to the estimation of the last significant figure.
The more trials run, the less random error will affect your results.

63. Dimensional Analysis (Conversions) GPS Resource Notes pp
Dimensional Analysis (Conversions) GPS Resource Notes pp Math Guided Practice p. 4

64. Homework Complete Accuracy vs Precision Practice
Complete Dimensional Analysis Practice
Complete Parts of Experiment Practice

65. Density GPS 2 Resource Notes p. 13 Math Guided Practice p. 6

66. Laboratory Techniques GPS 2 Resource Notes p. 1