1. CHEMISTRY
July 30, 2013

2. Brain Teaser Turn in Homework: Science Autobiography
Write your name and period number
Define Chemistry using your own words
What is the SI base unit for the following measurements (Example: Volume = Liter (L))
Length = ___________
Mass = __________
Temperature = ___________
Time = __________

3. Agenda Brain Teaser Notes: Homework Introduction to Chemistry
SI Units and Base Units
Significant Figures
Homework
Intro to Measurement Worksheet 1
Significant Figures Worksheet (?)

4. Unit 1 Objectives Introduction to Chemistry
Define chemistry and matter
Units of measurement
SI Units
Base Units
Accuracy versus Precision
Uncertainty in Measurement
Significant Figures
Significant Figures in Calculations
Dimensional Analysis

5. Introduction to Chemistry
Chemistry: The Central Science
Chemistry is the science that investigates and explains the structure and properties of matter.
Seeks to explain the submicroscopic events that lead to macroscopic observations

6. Branches of Chemistry Branch Area of Emphasis Examples
Organic chemistry
most carbon-containing chemicals
pharmaceuticals, plastics
Inorganic chemistry
in general, matter that does not contain carbon
minerals, metals and nonmetals, semi-conductors
Physical chemistry
the behavior and changes of matter and the related energy changes
reaction rates, reaction mechanisms
Analytical chemistry
components and composition of substances
food nutrients, quality control
Biochemistry
matter and processes of living organisms
metabolism, fermentation

7. SI Units (Le Systéme Internationale)
Units of measurement
SI Units (Le Systéme Internationale)
Scientists need to report data that can be reproduced by other scientists. They need standard units of measurement.
Base Units Le
A base unit is a defined unit in a system of measurement
There are seven base units in SI. 7

8. Base Units Official definitions of the seven base units 8

9. Metric staircase 9

10. SI Units and Base Units
Handouts
Kilo, centi, milli

11. SIGNIFICANT FIGURES

12. Significant Figures Significant Figures
Digits in a measurement that have meaning relative to the equipment being used 12

13. Significant Figures Place What is the increment on the equipment?
What you know for sure. 13

14. Significant Figures Digits with meaning
Digits that can be known precisely plus a last digit that must be estimated. 14

16. Scale Reading and Uncertainty
Uncertainty: Limit of precision of the reading (based on ability to guess the final digit).
Existed in measured quantities versus counted quantities
Refer to Example (2 rulers)
Addition and substraction(no. of sig. figs)
Division and Multiplication (no. of sig. figs)

17. Ruler
What are the units?

18. Graduated Cylinder
/labdocs/catofp/measurea/volume/gradcyl/gradc yl.htm
What are the units?

19. Significant Figures What do you notice?
Depends on type of equipment being used.
Depends on size of equipment used. 19

20. Summary Things to consider
What do significant figures tell you about the measurement on the equipment?
If you wanted to measure the mass of a whale, what scale would you want to use? Would it matter if you know its mass accurately to 1 gram?
If you wanted to measure the mass a grain of sand , what scale would you want to use? Would it matter if you know its mass accurately to 1 gram? 20

21. Significant Figures Raw Data Rules All digits 1-9 are significant.
How do you know how many sig figs?
All digits 1-9 are significant.
Zeros between significant digits are always significant.
Trailing 0’s are significant only if the number contains a decimal point
Zeros in the beginning of a number with a decimal point are not significant.
Zeros following a significant number with a decimal are significant. 21

22. Significant Figures Pacific to Atlantic Rule Examples
Pacific = Decimal Present
Start from the Pacific (left hand side), every digit beginning with the first 1-9 integer is significant
= 3 sig digits
= 6 sig digits
= 4 sig digits 22

23. Significant Figures Atlantic Rule to Pacific Examples
Atlantic = Decimal Absent
Start from the Atlantic (right hand side), every digit beginning with the first 1-9 integer is significant
= 5 sig digits
1000 = 1 sig digits 23

24. Practice
How many significant figures are in
400.0
4000
4004
0.004 24

25. More Practice Problems
Determine the number of significant figures in the following:
1.005
1000.
2002

26. Review Questions Determine the number of significant figures in:
4.05 x 105 g
4500. g

27. Homework
Measurement Worksheet 1
Significant Figures 1 Worksheet

28. THE END

29. Why do we use the metric system?
Advantages
Simple to use
Easy to convert from one unit to another
Dimensional Analysis
Universal – used worldwide
By all scientists to communicate
By all industrialized nations
Except United States
U.S. loses billions of dollars in trade

30. Mass versus Volume Question:
What is the difference between mass and volume?

31. Introduction to Chemistry
Chemistry: The Central Science
A more formal definition of Matter is anything that takes up space and has mass
Mass is the measure of the amount of matter that an object contains
Volume is the amount of space an object takes up.
Ask Question of two spherical object…which one has a larger volume?

32. Example Refer to the two identical spherical objects below
Bowling Ball
Volley Ball

33. Example Which of the following weighs more? A ton of feathers?
A ton of bricks?

34. SI Units (Le Systéme Internationale)
Units of measurement
SI Units (Le Systéme Internationale)
Scientists need to report data that can be reproduced by other scientists. They need standard units of measurement.
Base Units Le
A base unit is a defined unit in a system of measurement
There are seven base units in SI.

35. Base Units Official definitions of the seven base units

36. Metric staircase

37. Why do we use the metric system?
Advantages
Simple to use
Easy to convert from one unit to another
Dimensional Analysis
Universal – used worldwide
By all scientists to communicate
By all industrialized nations
Except United States
U.S. loses billions of dollars in trade

38. Example Convert 3400 milliliters to liters 44 centimeters to meters
277 kilograms to grams

39. Accuracy Versus Precision
What is the difference between accuracy and precision?

40. Precision versus Accuracy
Precision: is a measure of how closely an individual measurements agree with one another
Can be precise but inaccurate
Accuracy: refers to how closely individual measurements agree with the correct, or “true” value
Examples using the dartboard

41. An archery target illustrates the difference between accuracy and precision.

42. Accuracy and Precision Measurements

43. Scale Reading and Uncertainty
Uncertainty: Limit of precision of the reading (based on ability to guess the final digit).
Existed in measured quantities versus counted quantities
Addition and substraction(no. of sig. figs)
Division and Multiplication (no. of sig. figs)

44. Example
Which electronic balance below allows you to obtain a more precise measurement? Why?
Tenth versus hundred precision…it is more precise. A B

46. Triple Beam Balance
online.com/objects/index_tj.asp?objID=GCH202
What are the units?

47. Ruler
What are the units?

48. Graduated Cylinder
/labdocs/catofp/measurea/volume/gradcyl/gradc yl.htm
What are the units?

50. Measurement Activity Objectives
Measure each physical quantity to the maximum accuracy allowed by the appropriate instrument.
Record measurements and calculations with the appropriate units from the international system of units (SI.)

51. Measurement Activity Set up assignment Station Rotation
Title, Name, Chemistry, Period, Date
Station Rotation
10 Station
3-4 minutes at each station
Refer to Handout
Do NOT remove any items from the station
Clean Up and Restore each station before switching

53. Homework Homework “Is it worth the risk?” worksheet
Sign Lab Safety Contract
Study for Lab Safety Test (Monday)
Get Supplies for Chemistry

54. Closure Reflect on your learning during the lab activity
Concepts learned?
“Ah-ha” moments?
Questions?

55. Significant Figures

56. Rules for zeros: All zeros count except placeholder zeros
These are the ones that disappear when you write the number in scientific notation.
Zeros between nonzero digits are always significant
E.g kg (4 sig. fig) and 1.03 (3 sig. fig)
Zeros at the beginning of a number are never significant
E.g (1 sig. fig) and (2 sig. fig)
Zeros at the end of a number are significant if the number contains a decimal point
0.0200g (3 sig. fig), 3.0 cm (2 sig. fig), 5000 (1 sig. fig)

57. Rules for recognizing significant figures
Non-zero numbers are always significant.
Zeros between non-zero numbers are always significant.
All final zeros to the right of the decimal place are significant.
Zeros that act as placeholders are not significant.
Counting numbers and defined constants have an infinite number of significant figures.

58. Review Questions
Determine the number of significant figures in the following:
1.005
1000.
2002

59. Review Questions Determine the number of significant figures in:
4.05 x 10^5 g
4500. g

60. Closure
Reflect on your learning today

61. Homework Measurement Worksheet 2 Science Safety Test Element Quiz
Wednesday = TOMORROW
Element Quiz
Thurs/Fri
Lab Notebook
Quadrille Lab Notebook (Graphing paper) OR
Carbonless Copy Lab Notebook

62. Topics on Unit 1 Test Lab Safety Measurements SI units
Significant Figures, Uncertainty
Accuracy and Precision
Understanding Equipments
Dimensional Analysis

64. Intro to Dimensional Analysis