1. Chem 140 Section A Instructor: Ken Marr
Weekly Schedule
“Lecture” , MWF in STB-2
“Lab” , Tu in STB-2
8 -10 , Th in STB-5

2. Chem 140 Section C Instructor: Ken Marr
Weekly Schedule
“Lecture” –11, MWF in STB-2
“Lab” , Tu in STB-2
10-12 , Th in STB-5

3. Chem 140 Section E Instructor: Ken Marr
Weekly Schedule
“Lecture” , MWF in STB-2
“Lab” , Tu in STB-2
1 - 3 , Th in STB-5

4. Day 1 Activities Introduction to Course Homework Assignments
Briefly Review Course Outline/Syllabus
Homework Assignments
Reading: See Chem 140 schedule
Lab: Do Prelab assignment for the “Measurement and Density” Lab
Stamped Assignment #1: Chapter 1 HW
due Tues. 10/01/02 ……But start now!!!
Note: 10/2 is a very special day for your instructor!!
Begin Chapter 1
Alice 1 and 2

5. CHEMISTRY The Study of Matter and the Changes that Matter
Undergoes and
The Energy
Associated with
The Changes

6. Chemistry as the Central Science
Engineering
Physics
Atmospheric
Sciences
Oceanography
Medicine
Economics
Governments
Chemistry
People
Geology
Biology
Politics
Astronomy
Anthropology

7. Chapter# 1 : Keys to the Study of Chemistry
1.1 Some Fundamental Definitions
1.2 Chemical Arts and the Origins of
Modern Chemistry
1.3 The Scientific Approach: Developing a Model
1.4 Chemical Problem Solving
1.5 Measurement in Scientific Study
1.6 Uncertainty in Measurement:
Significant Figures

8. Measurement and Significant Figures
Measured Numbers are Never Exact...Why?
Which Graduated Cylinder is the most precise?
How is precision indicated when we record a measurement?

9. The Number of Significant Figures in a Measurement Depends Upon the
Measuring Device
Fig e

10. Significant Figures
We use significant figures to indicate the maximum precision of a measurement
Significant Figures
The number of digits that are known with certainty, plus one that is uncertain
Significant figures are used only with measured quantities.
Some numbers are exact and do not have any uncertainty......e.g...’s??

11. More Examples Record the exact length in centimeters, cm (T2c)
Record the exact amounts for numbers 1-11 (T2d)

12. Sig. Fig. Rules to memorize..... (See page 27-30 Silberberg 3e)
All nonzero numbers are significant
e.g g, km, mL, 5 inches
Zeros between nonzero digits are significant i.e. Sandwiched zeros are significant
e.g m, mL, L
Zeros preceding the 1st nonzero digit are not significant they serve only to locate the decimal point
e.g m, L
Try converting these numbers to Scientific Notation to prove this!

13. More Sig. Fig. Rules Involving Zeros
Zeros at the end of number that include a decimal point are significant
0.800, , ,
Zeros at the end of a number without a decimal point are not significant... The Greenwater Rule!
40, , ,
Use of underlining and decimal points

14. Examples of Significant Digits in Numbers
Number Sig digits Number Sig digits
L x 107 nm
kg ,000 L
L ,002.3 ng
g g
875,000 oz x 10 -6L
30,000 kg oz
m kg
23, lbs ml
g kg
1,470,000 L ,000,000,000 g

15. Rounding off Numbers
Rounding off is used to drop non-significant numbers
Rule 1
When the 1st digit after those you want to retain is 4 of less, that digit and all others to the right are dropped
Round off the following to 3 sig. figs.
105.29, , , ,

16. Rounding off Numbers Rule 2
When the 1st digit after those you want to retain is 5 or greater, that digit and all others to the right are dropped and the last digit retained is increased by one
Round off the following to 4 sig. figs.
, , ,

17. Sig. Figs. in Calculations
The Central Idea.....
The result of a calculation based on measurements can not be more precise than the least precise measurement!
Some Rules to, yes, memorize......

18. Sig. Figs. in Multiplication and Division
“The Chain Rule”
Your answer must contain the same number of sig figs as the measurement with the fewest sig figs.....Some e.g...’s...
(3.04) x (2.2) = = ???
(2.00) / (0.3 ) = = ???
(18.4) x (4.0) = = ???
(66.2)

19. Sig. Figs. in Addition and Subtraction
“The Decimal Rule”
The answer must have the same precision as the least precise measurement...or...
Your answer must be expressed to the same number of decimal places as the measurement with the fewest decimal places.
The number of sig figs are not considered, only the number of decimal places are considered!!!
Some examples..

20. Sig. Figs. in Addition and Subtraction
Examples.....
= = ?
= = ???
= = ???

21. Scientific Notation Scientific Notation The Rules...
Writing a number as a number between 1 and 10 times a power of 10
WHY DO IT???
The Rules...

22. How to Write Numbers in Scientific Notation
Move the decimal point in the original number so that it is located after the first nonzero digit
e.g  ????
Multiply this number by the proper power of 10
The power of 10 is equal to the number of places the decimal point was moved.
POSITIVE IF MOVED TO THE LEFT
NEGATIVE IF MOVED TO THE RIGHT

23. Examples.... Express the following numbers in scientific notation...
0.0421
150,000
5899
Express the following in “longhand”
5.30 x 10-4
8.000 x 106

24. Meaning of Powers of 10
103 = =
102 = =
101 = =
100 =

25. Metric System System of measure built around standard or base units
Uses factors of 10 to express larger or smaller numbers of these units

26. Physical Quantity Unit Name Abbreviation
Table 1. 2 (p. 17, 3e) SI - Base Units
Physical Quantity Unit Name Abbreviation
Mass Kilogram kg
Length meter m
Time second s
Temperature Kelvin K
Electric current ampere A
Amount of substance mole mol
Luminous intensity candela cd

27. Metric Base Units and their Abbreviations
Length
Mass
Volume
Temperature
Prefixes are added to these base units for quantities larger or smaller than the base unit
Prefixes are a multiple of 10

28. Prefix Prefix Number Word Exponential Symbol Notation
Table Common Decimal Prefixes Used with SI Units.
Prefix Prefix Number Word Exponential
Symbol Notation
tera T ,000,000,000, trillion
giga G ,000,000, billion
Mega M ,000, million
Kilo k , thousand
hecto h hundred
deka da ten
one
deci d tenth
centi c hundredth
milli m thousandth
micro millionth
nano n billionth
pico p trillionth
femto f quadrillionth

29. Common Metric Prefixes
Memorize the Symbol, Numerical Value, and Power of 10 Equivalent for.....
kilo-
centi-
milli-
micro-
nano-

30. Common Prefix Applications
Length:
km km = ? m
cm cm = ? m
mm mm = ? m
µm µm = ? m
nm nm = ? m

31. Common Prefix Applications
Mass
kg kg = ? g
mg mg = ? g
µg µg = ? g

32. Common Prefix Applications
Volume
mL mL = ? L
µL µL = ? L

33. Important Relationships
Length
1 m = ?? cm
1 m = ?? mm
1 m = ?? µm
1 cm = ?? mm

34. Important Relationships
Mass
1 g = ?? mg
1 kg = ?? g
1 kg = ?? lb..

35. Some Volume Relationships in SI Units
Fig. 1.9

36. Important Relationships
Volume
1 L = ?? mL
1 mL = ?? cm3
1 L = ?? cm3
1 L = qt.

37. Solving Chemistry Problems Develop a Plan  Carryout Plan  Check Answer
Developing a Plan: Read the problem carefully!
Clarify the know and unknown:
What information is given?
What are you trying to find?
Think about how to solve the problem before you start to juggle numbers
Suggest steps from the known to unknown
Determine principles involved and the relationships needed
Use sample problems as a guides
Map out the strategy you will follow

38. Solving Chemistry Problems (cont.)
Solve the problem: Carry out your plan
Set up problem in a neat, organized, and logical way!
Unwanted units should cancel to give the desired unit of measure
Make a rough estimate of the answer before using your calculator
Round off to correct number of sig. figs.
Answer must have correct units

39. Solving Chemistry Problems (cont.)
Check your answer
Is it reasonable?
Correct nits?
Same “ballpark” as a rough estimate?
Makes chemical sense?

40. Problem Solving: Some Examples
How many hours would it take a pump to remove the water from a flooded basement that is about 30 feet wide and 50 feet long with water at a depth of about 2 feet? The pump has a capacity of 80 liters per minute. See Table 1.4, Common SI-English Equivalent Quantities, page 18 Silberberg 3e.
1062 min = 17.7 hours = 20 hours

41. Metric Conversion Factors
Be able to do conversions within the metric system involving the common metric prefixes
kilo-
centi-
milli-
micro-
nano-
e.g. #32 on page 43

42. Metric - English Conversions
Given metric - English conversion factors, be able to convert between these two systems
You do not have to memorize metric to English conversions factors

43. Measurement of Temperature
Heat vs. Temperature
Temperature (SI unit: Kelvin, K)
A measure of how hot or cold an object is relative to another object
Also measured in degrees Celsius, oC
Heat (SI unit: joule, J)
The energy transferred between objects at different temperatures
A form of energy associated with the motion of atoms and molecules (the small particles of matter)
Also measured in calories, cal

44. Application: Heat vs. Temperature
Which contains more heat...
1 mL of water at 90 oC or 1 liter of water at 90 oC ?
1 burning match or 10 burning matches?

45. Temperature Conversions
The boiling point of Liquid Nitrogen is oC, what is
the temperature in Kelvin and degrees Fahrenheit?
T (in K) = T (in oC)
T (in K) = = K = 77.4 K
T (in oF) = 9/5 T (in oC) + 32
T (in oF) = 9/5 ( oC) +32 = oF
The normal body temperature is 98.6oF, what is it in Kelvin
and degrees Celsius?
T (in oC) = [ T (in oF) - 32] 5/9
T (in oC) = [ 98.6oF - 32] 5/9 = 37.0 oC
T (in K) = T (in oC)
T (in K) = 37.0 oC = 310.2

46. Density Density = mass (g) / Volume (mL or cm3 or L)
Physical characteristic of a substance
Aids in identification of a substance
Calculated by.....
divide the mass of a substance by the volume occupied by that mass
Units
mass in grams
volume
Solids and Liquids: mL or cm3
Gasses: L

47. Density Densities vary with temperature!
Why??
Would you expect densities to increase or decrease as the temperature increases?

48. Density
Immiscible liquids and solids separate into layers according to their densities
List the order from top to bottom when the following are mixed
Hg ( g/mL)
Carbon Tetrachloride ( g/mL)
Mg ( g/mL)
Water (1.004 g/mL)
What do the superscripts mean next to each density listed above?

49. Calculations Involving Density
Be able to calculate the density, mass, or volume of a substance
Use the plug and chug method or use density as a conversion factor
Practice makes perfect....

50. Specific Gravity
Compares the density of a liquid or solid to that of water... Units???
Sp. Gravity = dsolid or liquid / dwater
Usually use 4oC = 1.000g/mL
Compares the density of a gas to that of air Units???
Sp. Gravity = dgas/ dair

51. Mass vs. Weight Mass Amount of matter in an object
Independent of location
Measure with a balance by comparison with other known masses

52. Mass vs. Weight
Weight
Measures earth’s gravitational attraction on an object
Measure with a scale
measures force against a spring
Depends on
position relative to earth
motion of object w.r.t. the earth

53. Scientific Approach: Developing a Model
Observations : Natural phenomena and measured events; universally
consistent ones can be stated as a natural law.
Hypothesis: Tentative proposal that explains observations.
Experiment: Procedure to test hypothesis; measures one variable
at a time.
Model (Theory): Set of conceptual assumptions that explains data
from accumulated experiments; predicts related
phenomena.
Further Experiment: Tests predictions based on model.