Notes
Slide Show
Outline
1
"Professor"
  •  Professor  Abdul Muttaleb Jaber
  •  Chemistry Department
  •  Office: Room # 261F
  •  Tel: 2611
  •  E-mail: amjaber@kfupm.edu.sa
  • Office hours:  S  9-10; 11-12 am
  •      U 9-10 am
  •      M 9-10; 11-12 am
2
 
3
Chapter 1
Chemical Foundations
  • An overview
  • The scientific method
  • Units of measurements
  • Uncertainty in measurements
  • Significant figures and
  •   calculations
  • Dimensional analysis
  • Temperature
  • Density
  • Classification of matter
4
1.1 Chemistry: an overview
  • Matter is composed of atoms
  • Atoms are found as individuals or molecules
  • Atoms and molecules are connected by electrons
  • The challenge of chemistry is to think of the material the atomic level
  • 100 different types of atoms form all substances in the world
5
"Matter is composed of various..."
  • Matter is composed of various types of atoms or molecules.
  • Water is composed of O and H; H2O
  • An electric spark causes a mixture of O2 and H2 to explode forming H2O.
  • One substance changes to another by
  •    reorganizing the way atoms attached to each other


6
Scientific method
  • It is a way of solving problems
  • It consists of the following steps:
    • Observation- what is seen or measured
    • Hypothesis- guess of why things behave the way they do. (possible explanation for an observation)
    • Experiment- designed to test hypothesis
  • These steps would lead to new observations, and the cycle goes on
  • Once a set of hypotheses agree with
  •     observations, they are grouped into a theory
7
Scientific method
  • Thery  is a set of tested hypothesis that gives an overall explanation for a natural phenomenon
  • Laws are summaries of observations
  •       Often mathematical relationship
8
1.3 Units of measurements
  • Every measurement has two parts
  • Number
  • Scale (called a unit)
  • SI system (le Systeme International in French) based on the metric system
  • Examples:
  • 20 grams
  • 20    k   g   = 20 X103 g
  • 20    m  g  = 20 X10-3 g
  • 6.63 ´ 10-34 Joule seconds
9
Metric System
  • Fundamental SI base Units
  • Mass - kilogram (kg)
  • Length- meter (m)
  • Time - second (s)
  • Temperature- Kelvin (K)
  • Electric current- ampere (amp, A)
  • Amount of substance- mole  (mol)
10
Prefixes used in SI units
  • giga- G 1,000,000,000 109
  • mega - M 1,000,000 106
  • kilo - k 1,000 103
  • deci- d 0.1 10-1
  • centi- c 0.01 10-2
  • milli- m 0.001 10-3
  • micro- m 0.000001 10-6
  • nano- n 0.000000001 10-9
11
Volume measurement: Liter
  • Liter is defined as the volume of 1 dm3
    • 1 dm3 =
    • (10cm)3 =
    • 1000 cm3 =
    • 1000mL
12
 
13
Mass and Weight
  • Mass is measure of resistance to change in motion
  • Weight is force of gravity.
  • Sometimes used interchangeably
  • Mass can’t change, weight can
14
Electronic Analytical
Balance
15
Errors in Measurement
16
Types of Errors
  • Random Error (Indeterminate Error) - measurement has an equal probability of being high or low.
  • Systematic Error (Determinate Error) - Occurs in the same direction each time (high or low), often resulting from poor technique of measurement or bad equipment.
  • You can have precision without accuracy
  • You can’t have accuracy without precision (unless you’re really lucky).


17
 
18
Uncertainty in Measurement
  •  A measurement always has
  •    some degree of uncertainty.
  •  Uncertainty has to be indicated in any measurement.
  •  Any measurement has certain digits and one uncertain digit.
  • A digit that must be estimated is
  •    called uncertain.
  •  The number of certain digits + the uncertain digit is called number of significant figures.
19
 
20
Precision and Accuracy
  •  Accuracy: Agreement of a particular value to the true value (degree of correctness)
    • Measurements that are close to the “correct” value are accurate.
  • Precision: The degree of agreement among several measurements of the same quantity (degree of repeatability).
    • Measurements that are close to each other are precise.

21
Precision and Accuracy
22
 
23
"For multiplication and division"
  • For multiplication and division
  • the results are reported to the least number of significant figures


  •     354.760  X 0.0004567 = 0.162018892
  •     =  0.1620
  • For addition and subtraction
  • The results are reported to the least number of  decimal places
  •     345.672 – 34.56720 = 311.1048
  •                                      = 311.105
24
Rules for Counting Significant Figures
  • Nonzero integers always count as significant figures.
  • 3456 has
  • 4 sig figs.
25
"Zeros"
  • Zeros
  • Leading zeros do not count as significant figures.
  •    (Zeros before the nonzero digit)
  • 0.0486 has
  • 3 sig figs.
  • 0.0003 has
  • one significant figure
26
"Zeros"
  • Zeros
  • Trailing zeros are significant only
    • if the number contains a decimal point.
  • 9.300 has
  • 4 sig figs.
27
"Exact numbers have an infinite..."
  • Exact numbers have an infinite number of significant figures.
  • 1 inch  =  2.54 cm, exactly
28
Scientific Notation



29
Rules for Rounding Off
  • To get the correct number of significant digits
  •  you need to round numbers
  • In a series of calculations get one extra digit then
  • round
  • If the digit to be removed
    • is less than 5, the preceding digit stays the same
    • is equal to or greater than 5, the preceding digit is increased by 1
  • Don’t forget to add place-holding zeros if necessary to keep value the same!!
30
Multiple computations

  • 2.54  X  0.0028 =
  • 0.0105 X 0.060
  • 1)  11.3 2)  11     3)  0.041


  • Continuous calculator operation =
  •  2.54   x 0.0028    ¸   0.0105   ¸    0.060
31
"Here"


  • Here, the mathematical operation requires that we apply the addition/ subtraction rule first, then apply the multiplication/division rule.





32
1.6  Dimensional Analysis
  • Using the units to solve problems
33
Dimensional Analysis
34

How many minutes are in 2.5 hours?
  • Initial unit
  • 2.5 hr
  •                 Conversion          Final
  •   factor            unit
  • 2.5 hr   x    60 min       =   150 min
  •                      1 hr








35
"How many seconds are in..."

  • How many seconds are in 1.4 days?


  • Unit plan:   days        hr         min        seconds


  • 1.4 days   x   24 hr     x    ??
  •     1 day
36
Multiple units
  • The speed limit is 65 mi/hr. What is this in m/s?
    • 1 mile = 1760 yds
    •  1 meter = 1.094 yds

37
If you are running  at a speed of 65 meters per minute, how many seconds will it take for you to walk a distance of  8450 feet?

  • Initial
  • 8450 ft      x  12 in.     x   2.54 cm    x   1 m
  •    1 ft             1 in.         100 cm
  •        x   1 min      x   60 sec    =   2400 sec
  •              65 m   1 min
38
Units to a Power
  • How many m3 is 1500 cm3?
39
1.7   Temperature
  • Define the three  temperature scales: Celsius , Fahrenheit and Kelvin
  • Perform conversion from one to another.
40
Units of Temperature between Boiling and Freezing
  •          Fahrenheit Celsius Kelvin


  • Water boils    212°F                100°C   373 K


  •                       180°      100°C               100K


  • Water freezes  32°F                    0°C 273 K




41
 
42
1.8   Density
  • Density is the mass of substance
  •   per unit volume of the substance:
43
Densities of Various Common Substances* at 20° C
44
Density Problem
  • An empty container weighs 121.3 g. When filled with a liquid (density 1.53 g/cm3 ) the container weighs 283.2 g. What is the volume of the container?
45
1.9  Classification of Matter
  • Matter:  Anything occupying space and having mass.
  • Three States of Matter:
  • Solid:  rigid - fixed volume and shape
  • Liquid:  definite volume but assumes the shape of its container
  • Gas:  no fixed volume or shape - assumes the shape of its container
46
Types of Mixtures
  •  Matter could be pure (one component only)  or mixture
  •  Mixtures have variable composition (more than one component)
  • A homogeneous mixture has visibly indistinguishable components usually called a solution (for example, tap water)
  • A heterogeneous mixture has visibly distinguishable components, clearly not uniform (for example milk)


47
Organization of Matter
48
 
49
Properties of Matter
50
 
51
 
52

Separation of Mixtures
53
Distillation
54
Distillation is a physical change:  No chemical change occurs when salt water is distilled.
55
Separation of Mixtures
56
Paper chromatography:  A Line of the mixture to be separated is placed at one end of a sheet
57
The Paper Acts as a Wick to Draw up the Liquid
58
Component with the weakest attraction for the paper travels faster
59
Compounds and elements
  • Element:  A substance that   cannot be decomposed into simpler substances by chemical means.