Chemistry 120
Chemistry 120Dr. J. F. C. Turner
409 Buehler Hall
Office 4-8591
Lab 4-9316
email [email protected]
Chemistry 120
• Lecture: 80%
• 6 Quizzes 25%
• 3 Examinations 25%
• Final 30%
• Lab: 20%
Chemistry 120
• Grade Cutoffs ‘
A 100 – 80 C+ 68 – 69.9
B+ 78 – 79.9 C 60 – 67.9
B 70 – 77.9 D 50 – 59.9
F 0 – 49.5
There is no curve
Chemistry 120
1. Matter, Measurement and the Scientific Method (Ch. 1)
2. Atoms, Molecules and Ions (Ch. 2)
3. Stoichiometry (Ch. 3)
4. Chemical reactions in Aqueous solution (Ch. 4)
5. Gases (Ch. 5)
6. Thermochemistry (Ch. 6)
7. Atomic Structure (Ch. 7)
8. Atoms, Electrons and the Periodic Table (Ch. 8)
9. Chemical Bonds (Ch. 9)
10. Molecular Structure (Ch. 10)
11. States of Matter and Intermolecular Forces (Ch. 11)
Chemistry 120
“People have now-a-days,” he said, “got a strange opinion that everything should be taught by lectures. Now I cannot see that lectures can do so much good as reading the books from which the lectures are taken. I know nothing that can be best taught by lectures, except where experiments are to be shown. You may teach chemistry by lectures. – You might teach making of shoes by lectures”.
Samuel Johnson to Boswell, 1766, A Guide to Old English 1991
Chemistry 120
Chemistry is an ancient science, with many hundreds of years of history.
Chymistry, an art whereby sensible bodies contained in vessels........are so changed, by means of certain instruments, and principally fire, that their several powers and virtues are thereby discovered, with a view to philosophy or medicine.
Samuel Johnson, A Dictionary of the English language 1755
Chemistry 120
Chymistry, an art whereby sensible bodies contained in vessels..are so changed, by means of certain instruments, and principally fire, that their several powers and virtues are thereby discovered, with a view to philosophy or medicine.
Dr. Samuel Johnson, (1709–1784)literary titan of the 18th century, essayist,lexicographer, poet,editor, critic, second most quoted person in the English language, after Shakespeare
Chemistry 120
The etymology of chemistry is based on the word alchemy, which, in turn, is based on the Greek ί or ί, found in the Decree of Diocletian against ‘the old writings of the Egyptians, which treat of the ί (transmutation) of gold and silver’.
Chemistry 120
‘....the old writings of the Egyptians, which treat of the ί (transmutation) of gold and silver....’Gaius Aurelius Valerius Diocletianus (240? – 311)
Chemistry 120
Chemistry 120
Experimentz of alkamye ·Þe poeple to deceyue.
William Langland (1332? – 1400?)
The vision of William concerning Piers Plowman. 1377
Les Très Riches Heures du Duc de BerryMarch Folio 3v
Chemistry 120
A modern definition of chemistry.....
That branch of physical science and research, which deals with the several elementary substances, or forms of matter, of which all bodies are composed, the laws that regulate the combination of these elements in the formation of compound bodies, and the various phenomena that accompany their exposure to diverse physical conditions.
Oxford English Dictionary http://dictionary.oed.com/
Chemistry 120
Chemistry is concerned with the structure and properties of matter as well as the interchange of matter by reaction.
It differs from the other natural sciences or physical sciences as it is
CREATIVE
and thus has elements of art and is a science nonetheless.
Chemistry 120
We ask the question:
What is matter?
- if we are to understand chemistry, we need to know what we mean by matter.
Chemistry 120
What is matter?
Matter is the material of which the physical world is composed – the fabric of the universe.
Chemistry 120
The Fabric of the Universe?
Chemistry 120
Some forms of matter I
Matter comes in many different forms........
Chemistry 120
Some forms of matter II
Matter comes in many different forms........
Chemistry 120
Defects on the surface of copper metal
Impurities in the surface of copper metal
Some forms of matter III
Chemistry 120
The Scientific Method
The Scientific Method is a way of thinking about the physical world which allows us to:
1 Rationalize what we observe
2 Predict what we may observe
3 Understand the underlying principles of the physical universe
Chemistry 120
The Scientific Method: Knowledge of the World
Knowledge comes in two forms
– ‘interior’ and ‘exterior’
Interior:Fred and Jane are in love.
If we take any Fred, is this Fred in love with Jane?
Exterior: The mass of a mole of iron atoms is 55.845 (2) gmol-1
If we take 1 mole of iron, it always has a mass of 55.845 (2) gmol-1
Chemistry 120
The Scientific Method: Knowledge of the World
Interior Knowledge comprises
revealed truths
- such truths are dependent on the person(s) involved.
Exterior Knowledge comprises
empirical or experimental truths
- such truths are measurable and are independent of person.
Chemistry 120
The Scientific Method: Natural Laws
We can define a Natural Law as the sum of human ‘exterior’ observations.
- All human observations fit with the natural law else it cease to be a law – some thing is missing and the natural law is not universal.
- Logic is not sufficient to explain Science as Science is based in Human Experience
Chemistry 120
The Scientific Method: Logic and the problem of ravens
We can state that
“All ravens are black”
which is equivalent to
“All non-ravens are non-black”
However, observation of e.g. a red car does not demonstrate the color of ravens
Chemistry 120
Structure Of The Scientific Method:
Hypothesis – an abstract model of the system in question
Experiment – the test of the hypothesis by careful procedures that control
the variables in the hypothesis that generate data
Interpretation and Modification
Chemistry 120
Structure Of The Scientific Method:
Hypothesis
Experiment
DataInterpretation
Modification of hypothesis
Chemistry 120
The Scientific Method: Scientific Knowledge
Scientific Knowledge is:
1. Reproducible
2. Testable
3. Predictive
4. Tentative
Chemistry 120
The Scientific Method: Natural Laws
We can define a Natural Law as the sum of human ‘exterior’ observations.
- All human observations fit with the natural law else it cease to be a law – some thing is missing and the natural law is not universal.
Chemistry 120
The Scientific Method: Reproducibility
If the structure and dynamics of the Universe can be explained by a non-random set of ‘Natural Laws’, then independent measurements of the same system MUST reproduce the same result.
Chemistry 120
The Scientific Method: Testability
As a ‘Natural Law’ is the sum of human experience of a system, then we must be able to test the system and derive ‘experience’ of the system.
Chemistry 120
The Scientific Method: Predictive
If the hypothesis about the system is correct, it must be able to predict properties of that system that we can measure.
Chemistry 120
Chemistry 120Matter, Measurement and the Scientific Method
The Scientific Method: Uncertainty
All ‘Natural Laws’ are uncertain and are subject to change when human experience runs contrary to these laws.
Relativity Newton’s Laws of Motion
Quantum Mechanics Newtonian Gravitation
Chemistry 120
Conservation of Mass and Energy
One of the most basic Natural Laws
Matter and Energy are neither created or destroyed
Chemical transformations, by reaction or through physical means, always conserve mass
Chemistry 120
Two Chemical processes...
one fast,
one slow
.......that both conserve
mass and energy.
Chemistry 120
Classification of Matter
Matter can be divided into two classes
– solids
– fluids
- gases
- liquids
Chemistry 120
Solids
• Rigid – they have shape
• Incompressible
• Have a definite volume
Chemistry 120 Fluids
• Have no shape
• Liquids are incompressible
• Gases are compressible
• A liquid has a volume but a gas has the volume of the container.
Chemistry 120
Chemical Composition of the World: Atoms 101
“indivisible, uncuttable”All matter is composed of atoms which cannot be further split into smaller portionsAtoms are completely solidAtoms are homogeneous, with no internal structureBetween atoms there is empty spaceAtoms differ in size
Democritus (c.460-c.370 B.C.)
Chemistry 120
John Dalton (1766-1844)
Chemical Composition of the World: Atoms 200
Chemistry 120
Chemical Composition of the World: Atoms 300
Thomson’s“blueberry muffin” modelElectrons embedded in a shell of positive charge
Rutherford’s modelElectrons randomly circulating around nucleus made of protons
Chemistry 120
The Chemical Composition
of the World
There are 112 distinct chemical building blocks or ELEMENTS which make up all known matter
• An element cannot be transformed into any other element by chemical means or by ‘conventional’ physical processes
• Elements can be combined to produce ‘compound bodies’ - compounds
Chemical Basics
Chemistry 120
Chemical Basics
Chemistry 120
Chemical elements are abbreviated with a symbol, usually but not always abbreviated to their name:
Calcium Ca Radon Rn
Barium Ba Magnesium Mg
Chlorine Cl Oxygen O
Chemical Basics
Chemistry 120
Elements, whose symbols are not always abbreviated to their name:
Sodium Na (Latin Natria)
Potassium K (Latin Kalia)
Silver Ag (Latin Argentum)
Gold Au (Latin Aurum)
Mercury Hg (Latin Hydrargyrum)
Tungsten W (from the mineral Wolframite)
Chemical Basics
Chemistry 120
Elements are combined into compounds, where the number of atoms in the compound is shown by a subscript
FeCl3C6H12O6 H2O CO2
Physical processes
Melting, boiling, crushing, evaporating, freezing
do not change compounds or elements
Chemical Basics
Chemistry 120
Chemical processes convert
Elements into compounds
Compounds into elements
Compounds into compounds
Chemical Basics
Chemistry 120
Elements and compounds are termed
Substances
which we can define as
A species of matter which is homogenous and with a definite chemical composition
Chemical Basics
Chemistry 120
Substances (elements or compounds) can form
Mixtures
which are either
heterogenous
- different in different places in the sample
or homogenous
- the same everywhere in the sample
Chemical Basics
Chemistry 120
Chemical Basics
An example of a heterogenous mixture is granite
- it appears to be one material but........
Chemistry 120
Chemical Basics
...it is composed of a mixture of minerals in varying proportion, where each point in the piece is not necessarily the same.
Chemistry 120
Chemical Basics
An example of a homogenous mixture is air which is composed of
Gas Mole percent Boiling point
Nitrogen (N2) 78.084 -195.79 °C
Oxygen (O2) 20.947 -182.9 °C
Argon (Ar) 0.934 -185.8 °C
An example of a homogenous mixture is air which is composed of
Air can be cooled to remove the oxygen and thus separate the mixture
Chemistry 120
Elements
Compounds
Heterogenous
MixtureHomogenous
Mixture
Substances
Physical changes
Chemical changes
Chemical Basics
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
Imagine we measure the mass of a ball bearing a number of times and we find that the mass is
1 4.76g 2 4.74g 3 4.75g
4 4.74g 5 4.75g 6 4.76g
The average mass is the sum of the masses divided by the number of measurements:
Chemistry 120
Scientific Measurement and Notation
Average mass = 4.76+4.74+4.75+4.74+4.75+ 4.766
Chemical Basics
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
Average mass = 28.5 6
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
Average mass = 4.75g
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
Average mass = 4.75g
but we know that there is uncertainty in the measurement in the last figure – it varies between 0.04 and 0.06.
So we say that there are two figures that are certain and one in which there is a small uncertainty and we say that there are
3 Significant figures
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
Average mass = 4.75g
but we know that there is uncertainty in the measurement in the last figure – it varies between 0.04 and 0.06.
So we say that there are two figures that are certain and one in which there is a small uncertainty and we say that there are
3 Significant figures
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
The Rules for Significant figures
1. All non-zero figures are significant
2. All zeros to the left of a non-zero figure are not significant e.g. 0.00593
3. All zeros between non-zero figures are significant e.g. 7.098532
4. All zeros to the right of non-zero digits are significant
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
In a multiplication or division calculation:
Give the answer only to the number of significant figures that occur in the measurement that has the smallest number of significant figures.
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
Density = = m/V
When m = 123g and V = 66ml,
= m/V = 123/66 = 1.86363636364gml-1
= 1.87gml-1
= 1.9gml-1
2 significant figures
Round up
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
In a addition or subtraction calculation:
Give the answer only to the number of significant figures that occur in the measurement that has the smallest number of decimal places.
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
17.421g + 1.92g =
1420ml + 0.1223ml =
Chemistry 120
Chemical Basics
Scientific Measurement and Notation
17.421g + 1.92g = 19.341g
= 19.34g
1420ml + 0.1223ml = 1420.1223ml
= 1420ml
Chemistry 120
Chemical Basics
Scientific Units
In science, we use SI (Systeme Internationale) exclusively.
For chemists, the most important are
Length meter m
Mass kilogram kg
Time second s
Temperature kelvin K (not oK!!)
Amount of substance mole mol
Chemistry 120
Units are important.......Mars Climate Orbiter (MCO) was launched in late 1998, followed by Mars Polar Lander (MPL) and Deep Space 2 launched in early 1999. MCO failed to achieve Mars orbit because of a navigation error, resulting in the spacecraft entering the Mars atmosphere instead of going into the planned orbit. ............. Spacecraft operating data needed for navigation were provided to the JPL navigation team by prime contractor Lockheed Martin in English units rather than the specified metric units. This was the direct cause of the failure.
Chemical Basics
~ $250m
Chemistry 120
Chemical Basics
Scientific Units
In science, we use SI (Systeme Internationale) exclusively.
For chemists, the most important are
Length meter m
Mass kilogram kg
Time second s
Temperature kelvin K (not oK!!)
Amount of substance mole mol
Chemistry 120
Chemical Basics
Scientific Units
Large or small fractions of the basic units, (m, kg, s, K) are written in scientific notation with the order of magnitude shown by a power of ten.
1200 m = 1.2 x 103 m
0.0012 m = 1.2 x 10-3 m
0.00000000012 g = 1.2 x 10-10g
Chemistry 120
Chemical Basics
67,000,000 s =
0.00005 K =
34 m =
4,500,000,000,000,000,000,000 m =
5,768,000 s =
Chemistry 120
Chemical Basics
67,000,000 s = 6.7 x 108 s
0.00005 K = 5 x 10-5 K
34 m = 3.4 x 101 m
4,500,000,000,000,000,000,000 m = 4.5 x 1021 m
5,768,000 s = 5.678 x 106 s
Chemistry 120
Chemical Basics
Scientific Units
We denote the powers of ten by a prefix to the unit symbol.
The common ones are
103 kilo km 10-2 centi cm
106 mega MJ 10-3 milli mm
109 giga Gpa 10-6 micro m
10-9 nano ns
Chemistry 120
Chemical Basics
Length defines the spatial extent of a body in one dimension.
The formal definition is
"The metre is defined as the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second"
Chemistry 120
Chemical Basics
Area defines the spatial extent of a body in two dimensions
L1
L2
A = L1 x L2
Unit of area is a derived unit – it is combination of other units. In this case they are the same – the square meter, m2.
Units are still OK for
circular areas: A = 4r2
Chemistry 120
Chemical Basics
Volume defines the spatial extent of a body in three dimensions
Unit of volume is a derived unit – it is combination of other units. In this case they are the same – the cubic meter, m3.
L1
L2
L3
V = L1 x L2 x L3
Units are still OK for
spherical volumes: V = 4/3r3
Chemistry 120
Chemical Basics
Area conversions
1 cm = 1 x 10-2 m
1 cm2 = (1 x10-2 m)2 = (1 x 1 x 10-2 x 10-2)m2
= 1 x 10-4 m2
1 cm
1 cm 1 cm2
Chemistry 120
Chemical Basics
Volume
1 cm = 1 x 10-2 m
1 cm3 =
Chemistry 120
Chemical Basics
Volume
1 cm = 1 x 10-2 m
1 cm3 = (1 x 10-2 m)3
=
Chemistry 120
Chemical Basics
Volume
1 cm = 1 x 10-2 m
1 cm3 = (1 x 10-2 m)3
= (1 x 1 x 1 x 10-2 x 10-2 x 10-2 ) m3
=
Chemistry 120
Chemical Basics
Volume
1 cm = 1 x 10-2 m
1 cm3 = (1 x 10-2 m)3
= (1 x 1 x 1 x 10-2 x 10-2 x 10-2 ) m3
= 1 x 10-6 m3
Chemistry 120
Chemical Basics
So if I know that 1 cm3 = 1 x 10-6 m3, 3.4 cm3 can be found in m3 by
1 cm3 = 1 x 10-6 m3
Chemistry 120
Chemical Basics
So if I know that 1 cm3 = 1 x 10-6 m3, 3.4 cm3 can be found in m3 by
3.4 x 1 cm3 = 3.4 x 1 x 10-6 m3
Chemistry 120
Chemical Basics
So if I know that 1 cm3 = 1 x 10-6 m3, 3.4 cm3 can be found in m3 by
3.4 x 1 cm3 = 3.4 x 1 x 10-6 m3
3.4 cm3 = 3.4 x 10-6 m3
Chemistry 120
Chemical Basics
So if I know that 1 cm2 = 1 x 10-4 m2, 78 cm2 can be found in m2 by
1 cm2 = 1 x 10-4 m2
Chemistry 120
Chemical Basics
So if I know that 1 cm2 = 1 x 10-4 m2, 78 cm2 can be found in m2 by
78 x 1 cm2 = 78 x 1 x 10-4 m2
Chemistry 120
Chemical Basics
So if I know that 1 cm2 = 1 x 10-4 m2, 78 cm2 can be found in m2 by
78 x 1 cm2 = 78 x 1 x 10-4 m2
78 cm2 = 78 x 10-4 m2
Chemistry 120
Chemical Basics
So if I know that 1 cm2 = 1 x 10-4 m2, 78 cm2 can be found in m2 by
78 x 1 cm2 = 78 x 1 x 10-4 m2
78 cm2 = 78 x 10-4 m2
BUT 78 x 10-4 m2 = 7.8 x 101 x 10-4 m2
Chemistry 120
Chemical Basics
So if I know that 1 cm2 = 1 x 10-4 m2, 78 cm2 can be found in m2 by
78 x 1 cm2 = 78 x 1 x 10-4 m2
78 cm2 = 78 x 10-4 m2
BUT 78 x 10-4 m2 = 7.8 x 101 x 10-4 m2
SO 78 x 10-4 m2 = 7.8 x 10-3 m2
Chemistry 120
Distance to the Horizon 1026 m
Distance to M31 1022 m
Distance to the center of the galaxy 1020 m
Distance to the Nearest Star 1017 m
Distance of Earth to Sun 1011 m
Radius of Sun 108 m
Radius of Earth 106 m
Chemical Basics
Chemistry 120
Radius of Knoxville TN 104 m
A small cow 100 m
Unraveled human DNA strand 10-3 m
Typical size of dust 10-4 m
Typical size of a cell 10 -6 m
(1 micron, 1m)
Chemical Basics
Chemistry 120
Chemical Basics
The Planck Length 10-35 m
Radius of the proton: 10-18 m
Radius of Electron "orbit"
about an atomic nucleus 10-15 m
Wavelength of 1 MeV gamma-ray : 10-12 m
Spacing of atoms in solid copper : 10-10 m
(1 Ångstrom, 1Å)
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