1. Unit 1
The Math of Chemistry

2. Lab Safety

3. Lab Safety

4. How Many?
Try to guess how many molecules of water are in the graduated cylinder.
Actual number:

5. Scientific Notation Reflect Question:
What is scientific notation and why do we use it?

6. Scientific Notation and % Error
Consists of two numbers: 1st is between 1 and 9 (the coefficient), the second is a power of 10
The exponent/power indicates how many places to move the decimal.

7. Scientific Notation
1.32 x vs x 105

8. Scientific Notation and % Error
Write the following in scientific notation:
32,700 ________________
1,024,000 _____________
______________
____________
8960 __________________
________________

9. Scientific Notation and % Error
Write the following in standard notation:
x 10-4 ________________________
4.755 x 108 _________________________
5.60 x 10-5 __________________________
1.806 x 107 _________________________
3.0 x 101 ___________________________
5.28 x 10-2 __________________________

10. Rules for “fixing” a number when it isn’t in proper scientific notation:
Example 1: Example 2: 19.6 x x Rule: If you make one number bigger, make the other one smaller & vice versa.

11. Lab Equipment

12. Lab Equipment

13. Lab Equipment

14. Metric System

15. Metric System
Reflect:
In what way can we measure objects in science?

16. Measurement History
Up until the time of Napoleon, every country had its own measuring system.  This was based on the body part of the ruling monarch (thus the term ruler)  length was based on the length of the king’s foot (hence the measurement foot)  Weight was in stones. # of = sized stones = mass of the king.

17. How do you define a unit of measure?
Mass: The Kilogram Watt Balance Silicon Sphere

18. How do you define a unit of measure?
Length: The Meter 1793: 1960’s: 1980’s:

20. Metric System

21. Metric System

22. Metric System
When converting between units using the above “Metric Line”:
Mover you decimal in the same DIRECTION and # of SPACES you are moving on the “Metric Line”

23. Metric System
Example 1: Convert 5 meters into millimeters Example 2: Convert μS into seconds Example 3: Convert 83.2 centimeters into meters.

24. Metric System
Example 4: Convert 1.2 kiloliters into liters. Example 5: Convert 5 x μm to pm. Example 6: Convert 186 m to nm.

25. World’s Roundest Object
The Metric System at work!

26. Precision in Measurement
Reflect:
When taking a measurement (volume, length, mass) does it matter if all of the instruments you will use are accurate to a different number of decimal places?

27. Precision in Measurement
Reading & Taking Measurements in Science:
When we read measuring devices, our measurement
must take into account the capabilities of your
instrument.

28. Precision in Measurement
Question 1: Looking at the ruler below, to how many decimal places are you able to report your answer to? Question 2: Estimate the length of the object below.

29. Precision in Measurement
Precision: Reproducibility/ repeatability
Smaller variation = better precision
Accuracy: How close your measured value is to actual/accepted value

30. Precision in Measurement
Directions:
Below are two rulers, each measuring the same length of a piece of wire. Below each ruler are measurements reported for the wire. Decide whether each listed measurement is a valid measurement or not based on the scale of the ruler. Write a “V” for VALID measurement or an “I” for an INVALED measurement next to each measurement taken.

31. Precision in Measurement
2.9 cm: __________ 3.0 cm: ___________ 2.99 cm : _________ 3.01 cm : __________ 3 cm: ____________ 2.98cm: ___________

32. Precision in Measurement
3.00 cm: __________ 3.0 cm: ___________
2.99 cm : _________ cm : __________
3 cm: ____________ cm:__________

33. Precision in Measurement
Which ruler is a better choice for accurately measuring the length of the wire? Explain. The second ruler b/c it can be precise to a greater number of decimal places.

34. % Error
Reflect:
What is percent error?

35. % Error

36. Practice

37. Significant Digits Reflect:
When reporting a measurement or calculation, how many decimal places should your answer have? How do you figure it out?

38. Significant Digits in Measurement
Significant Digits (or Significant Figures): The significant figures of a number are those digits that carry meaning contributing to its precision.

39. Significant Digits in Measurement

40. Significant Digits in Measurement
5 Rules for Significant Digits
All non-zero numbers are significant
. Sandwiched zeros (those that occur between two significant digits) are
significant.
. Zeros that are only placeholders for a decimal are not significant.
. Zeros at the end of a number that also contains a decimal are significant.
. Exact numbers (no doubt or uncertainty in the value) may be thought of
as having an infinite number of significant digits. These include numbers
that were counted or are defined values (i.e. conversion factors).

41. Significant Digits in Measurement
5 Rules for Significant Digits
All non-zero numbers are significant
. Sandwiched zeros (those that occur between two significant digits) are
significant.
. Zeros that are only placeholders for a decimal are not significant.
. Zeros at the end of a number that also contains a decimal are significant.
. Exact numbers (no doubt or uncertainty in the value) may be thought of
as having an infinite number of significant digits. These include numbers
that were counted or are defined values (i.e. conversion factors).

42. Significant Digits in Measurement
5 Rules for Significant Digits
All non-zero numbers are significant
. Sandwiched zeros (those that occur between two significant digits) are
significant.
. Zeros that are only placeholders for a decimal are not significant.
. Zeros at the end of a number that also contains a decimal are significant.
. Exact numbers (no doubt or uncertainty in the value) may be thought of
as having an infinite number of significant digits. These include numbers
that were counted or are defined values (i.e. conversion factors).

43. Significant Digits in Measurement3
0.03
3.2
32,000
3.15
Just because we changed units, our measurement did not get more/less precise. The zeros we added are simply holding a place, they are not significant.

44. Significant Digits in Measurement
5 Rules for Significant Digits
All non-zero numbers are significant
. Sandwiched zeros (those that occur between two significant digits) are
significant.
. Zeros that are only placeholders for a decimal are not significant.
. Zeros at the end of a number that also contains a decimal are significant.
. Exact numbers (no doubt or uncertainty in the value) may be thought of
as having an infinite number of significant digits. These include numbers
that were counted or are defined values (i.e. conversion factors).

45. Significant Digits in Measurement
5 Rules for Significant Digits
. Exact numbers (no doubt or uncertainty in the value) may be thought of
as having an infinite number of significant digits. These include numbers
that were counted or are defined values (i.e. conversion factors).

46. Significant Digits in Measurement

47. Significant Digits in Measurement

48. Significant Digits in Measurement
When multiplying or dividing, limit your answer to the same number of significant digits as the digit with the least number of significant digits.
V = l x w x h
V = (3.052 m)(2.10 m)(0.75 m)
V = (4 sig figs)(3 sig figs)(2 sig figs)
V = m3
V = 4.8 m3

49. Significant Digits in Measurement
When adding or subtracting, limit your answer to the same decimal places as the factor with the least number of decimal places.
337.

50. Practice

51. Density Reflect: What is density?
 Write down any words, formulas, concepts, pictures, phrases, comparisons or numbers that will help you answer this question.

52. Density
Defining Density:
Words
Pictures
Mathematical Formula

53. Ways to Calculate the Density of an Object
Aluminum Bar
Rubber Stopper
A Liquid

54. Calculated Density for Each Object
Aluminum Bar
Rubber Stopper
A Liquid

55. Comparing Densities
Compare the MOST dense with the LEAST dense object, in terms of particle arrangement, citing evidence from your calculations.

56. Comparing Densities
The density of mineral oil is 0.8 g/mL, if all three substances were placed in the mineral oil would they sink or float? Explain.

57. Practice Problems

58. Practice Problems

59. Laboratory Equipment Graduated Cylinder Test Tube Beaker Funnel
Test Tube Clamp
Beaker Tongs
Erlenmeyer Flask
Clay Triangle

60. Laboratory Equipment Buret Scoopula Pipet Ring Stand Evaporating Dish
Crucible w/Cover
Watch Glass
Ring Stand

61. Laboratory Equipment Wire Gauze Bunsen Burner Rubber Stopper
Crucible Tongs
Hot Plate
Stirring Rod
Test Tube Rack
Electronic Scale

62. Lab Procedures
3.5
47.0 32

63. Lab Procedures

64. Lab Procedures
21.3
39.25
17.95

65. Lab Procedures

66. Lab Procedures