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Chemistry• the study of matter
• its chemical and physical properties• the chemical and physical changes it undergoes• the energy changes that accompany those
processes
• Most changes either require energy or produce energy
• This class will focus on the changes that happen in living systems
CHEMISTRY
medical practitioners
pharmaceutical industry
forensic sciences
food science
public health
Why do you need to know chemistry?
Bunny reproduction is biology!
+
Chemistry overlaps with many different disciplines.
Bunny reproduction is biology!
+
Chemistry overlaps with many different disciplines.
But chemists study the hormonal changes that
tell the bunnies when to mate!
Psychologists study how mice “learn”.
Chemistry overlaps with many different disciplines.
Chemistry overlaps with many different disciplines.
But chemists study the
neurotransmitters responsible for learning!
Psychologists study how mice “learn”.
What happens when a bunnybaby crosses a road is physics.
Chemistry overlaps with many different disciplines.
What happens when a bunnybaby crosses a road is physics.
Chemistry overlaps with many different disciplines.
What happens to the bunny baby’s bodyin the hot summer sun is chemistry!
Chemistry overlaps with many different disciplines.
MAJOR AREAS OF CHEMISTRY• Biochemistry - the study of life at the
molecular level• Organic chemistry - the study of matter
containing carbon and hydrogen • Inorganic chemistry - the study of matter
containing elements, not organic• Analytic chemistry - analyze matter to
determine identity and composition• Physical chemistry - attempts to explain the
way matter behaves
Chemistry uses the scientific method• How does something
work?• What is the “truth”
about how something works?
• Does my data support my hypothesis?
• Do I need to change my hypothesis?
Experimental methods• Experiments produce DATA & RESULTS • DATA:– Recorded observations or measurements• Mass, Time, Temp, volume, energy
• RESULTS:– Outcome of experiment– Conclusions drawn from observations– Usually several pieces of data form a result
CHEMISTRYthe study of matter
and its changes
. . . but what is matter?
Matter is “stuff ”
(anything with mass and volume)
CHEMISTRYthe study of matter
and its changes
hammer Q-tip fear paper bag beauty
blood talent acorn air gravity
Which of these are matter?
CHEMISTRYthe study of matter
and its changes
• Pure substance - a substance that has only one component
• Mixture - a combination of two or more pure substances in which each substance retains its own identity, not undergoing a chemical reaction
Classification of Matter
• Element - a pure substance that cannot be changed into a simpler form of matter by any chemical reaction
• Compound - a substance resulting from the combination of two or more elements in a definite, reproducible way, in a fixed ratio
Classification of Matter
• Mixture - a combination of two or more pure substances in which each substance retains its own identity
• Homogeneous - uniform composition, particles well mixed, thoroughly intermingled
• Heterogeneous – nonuniform composition, random placement
Classification of Matter
Classification of Matter• Which classes of matter are shown below?
compound Heterogeneous mixture
Homogeneous mixture
The Periodic Table of the Elements
The Periodic Table of the Elements
We know that all “matter” is made up ofvery, very, very tiny spheres called atoms.
Each square in this table represents a different kind of atom.
There are over 114 different kinds of atoms.
The Periodic Table of the Elements
Table organization is based on each atom’s makeup and thesimilarities of the properties of the various kinds of atoms.
We know that all “matter” is made up ofvery, very, very tiny spheres called atoms.
Each square in this table represents a different kind of atom.
The Periodic Table of the Elements
The Periodic Table of the Elements
The Periodic Table of the Elements
The Periodic Table of the Elements
We won’t discuss any of these elements in
PhysiologicalChemistry
Table is usually displayed this way.(it takes up less space)
The Periodic Table of the Elements
Every kind of atom has a name and a “symbol.”
The Periodic Table of the Elements
All modern symbols are based on letter abbreviations
Hydrogen (H)Oxygen (O)Iodine (I)
Every symbol startswith a capital letter.
The Periodic Table of the Elements
Some symbols have two letters.
Scandium (Sc)Bismuth (Bi)Neon (Ne)
First letter is capitaland second is lower case.
The Periodic Table of the Elements
Some symbols come from foreign languages.Tungsten (W) -- ‘W’ is from wolfram (German)
Sodium (Na) -- ‘Na’ is from natrium (Latin)Antimony (Sb) -- ‘Sb’ is from Stibium (Latin)
The Periodic Table of the Elements
Some types of atoms are very common in air!
nitrogen, oxygen, carbon, argon, neon, helium
The Periodic Table of the Elements
Some types of atoms are very common in dirt and rocks!
oxygen, silicon, aluminum, iron, calcium, sodium
The Periodic Table of the Elements
Some types of atoms are very common in stars!
hydrogen, helium, carbon, oxygen, neon, magnesium
The Periodic Table of the Elements
Some types of atoms are very common in human bodies!
oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus
The Periodic Table of the Elements
1 2 3 4 . . . . . . . . . . . . . . . . . . . . . . . . . 16 17 18
18 columns(Columns are called groups)
The Periodic Table of the Elements
This is group 13.
The Periodic Table of the Elements
7 rows(Rows are called periods)
1234567
The Periodic Table of the Elements
This is period 4.
The Periodic Table of the Elements
alkali metals(Group 1)
The Periodic Table of the Elements
alkaline earth metals(Group 2)
The Periodic Table of the Elements
halogens(Group 17)
The Periodic Table of the Elements
noble gases or “inert” gases(Group 18)
All of the atoms in a grouphave similar properties.
http://www.an.psu.edu/rxg1/pt1999/halogens.html
Consider these three halogens:
• All smell like a swimming pool.• All produce colored vapors.
• All react rapidly with sodium to give edible salts.
• All are poisonous.
Groups in the periodic table are comprised of elements with similar properties.
http://www.an.psu.edu/rxg1/pt1999/halogens.html
Consider these three halogens:
Consider these three alkali metals:
Lithium (Li)Sodium (Na)
Potassium (K)
• All are shiny, soft solids when pure.• All melt at very low temperatures.
Consider these three alkali metals:
Lithium mp = 181oCSodium mp = 98oCPotassium mp = 63oC
• All are shiny, soft solids when pure.• All melt at very low temperatures.• All react violently with water.
Consider these three alkali metals:
http://www.westga.edu/~chem/courses/desc.inorg/490Jan14/sld009.htm
The Periodic Table of the Elements
MetalsNon-metalsMetalloids or semimetals
Hydrogen is an odd-
ball!
The Periodic Table of the ElementsMetals are . . .
• Lustrous• Malleable
• Ductile• Conductors of
electricity• Prone to losing electrons • Lower Left of periodic
table
The Periodic Table of the ElementsNonmetals are . . .
• Not lustrous• Not malleable
• Not ductile• Not conductors of
electricity• Often prone to gaining electrons • Upper Right of
table
Classification & Behavior of Matter• Properties of Matter– Physical– ChemicalWhat are some examples of properties of matter?
• States of Matter– Solid– Liquid– Gas• Gas Laws
hydrogen + oxygen water
reactants products
Chemical Properties & Change• Property - result in a change in composition
and can be observed only through a chemical reaction
• Reaction (chemical change) - a process of rearranging, removing, replacing, or adding atoms to produce new substances
Physical Properties & Change• Property - is observed without changing the
composition or identity of a substance
• Change - produces a recognizable difference in the appearance of a substance without causing any change in its composition or identity- conversion from one physical state to another- melting an ice cube
Separation by Physical PropertiesMagnetic iron is separated from other nonmagnetic
substances, such as sand. This property is used as a large-scale process in the recycling industry.
Three States of Water
(a) Solid (b) Liquid (c) Gas
Three States of Matter• gas - particles widely separated, no
definite shape or volume solid
• liquid - particles closer together, definite volume but no definite shape
• solid - particles are very close together, define shape and definite volume
Solid Liquid Gasordered
condensednot orderedcondensed
not orderednot condensed
Comparison of states of matter
Solid Properties
Solids are . . .
•Not compressible
•Organized
But solids are more complex than this!
•Don’t take the shape of their container!
All solids are considered by chemists to be either crystalline or amorphous.
Crystalline: at the atomic level, material is highly organized and has a repeating pattern of particles
Amorphous: at the atomic level, material appears randomly thrown together and no patterns are present.
All solids are considered by chemists to be either crystalline or amorphous.
Crystalline: at the atomic level, material is highly organized and has a repeating pattern of particles
Ionic Solids
Covalent Solids
Molecular SolidsMetallic Solids
Ionic SolidsMolecular Solids
http://www.btinternet.com/~digital.wallpapers/hot_air_balloon.jpg
GasesGases
Some Gaseous Odds and Ends
Gases have very low densities
N2 (s) d = 1.03 g/mL
N2 (l) d = 0.808 g/mL (78%)
N2 (g) d = 0.00125 g/mL (0.12%)
(implied by “mostly empty space”)
Some Gaseous Odds and Ends
Gases readily expand to fill their container
(implies that gas molecules are moving rapidly)
Some Gaseous Odds and Ends
Gases are readily compressible
(implied by “mostly empty space”)
Some Gaseous Odds and Ends
Gases are readily compressible
(Liquids and solids are already compressed)
Some Gaseous Odds and Ends
And they “spring” back!
(implies that gases exert “pressure”)
Some Gaseous Odds and Ends
Gases exert “pressure” because gas molecules collide with container.
Area
forcePressure
Usually in2 or m2
Usually “pounds” or Newtons
2in
pounds2m
Newtons
Some Gaseous Odds and Ends
Gases exert “pressure” because gas molecules collide with container.
usually abbreviated as “psi”
2in
pounds2m
Newtons
Some Gaseous Odds and Ends
Gases exert “pressure” because gas molecules collide with container.
known as a “Pascal” (Pa)
2in
pounds2m
Newtons
Convert 34 psi to Pa.
Some Gas Problems
101,325 Pa = 14.7 psi
Papsi
Papsi 000,234
7.14
325,10134
What is blood pressure?
The liquid inside your blood vessels is
compressed by the elastic nature of the
vessel walls.
Your blood pressure is usually 80 mm Hg
greater than the atmospheric pressure
What is blood pressure?
The liquid inside your blood vessels is
compressed by the elastic nature of the
vessel walls.
When your heart contracts, the pressure
goes up even more!
. . . Perhaps to 120 mm Hg greater than atmospheric!
THE GAS LAWS
http://elementy.ru/images/eltbio/boyle_robert_180.jpg
In 1662, Robert Boyle discovered an inverse relationship between the pressure exerted by a
gas and its volume.
In 1662, Robert Boyle discovered an inverse relationship between the pressure exerted by a
gas and its volume.
1 atm
2 atm
4 atm
(As long as the temp was kept the same)
In 1662, Robert Boyle discovered an inverse relationship between the pressure exerted by a
gas and its volume.
Examine his data:
20 mL 1 atm = 20 mL.atm
10 mL 2 atm = 20 mL.atm
5 mL 4 atm = 20 mL.atm
In other words . . .
PV = constant
In 1662, Robert Boyle discovered an inverse relationship between the pressure exerted by a
gas and its volume.
PV = constant
This is known as Boyle’s Law
Using Boyle’s Law
When atmospheric pressure = 14.9 psi, a sample of air has a volume of 30 mL. What will the volume of the air sample be when atmospheric pressure drops to 14.5 psi?
PV = constant
First, let’s find the constant:
14.9psi 30mL = 447 psi.mL
When atmospheric pressure = 14.9 psi, a sample of air has a volume of 30 mL. What will the volume of the air sample be when atmospheric pressure drops to 14.5 psi?
14.5psi V = 447 psi.mL
Now, use the constant to find the new volume:
14.9psi 30mL = 447 psi.mL
Using Boyle’s Law
When atmospheric pressure = 14.9 psi, a sample of air has a volume of 30 mL. What will the volume of the air sample be when atmospheric pressure drops to 14.5 psi?
14.5psi V = 447 psi.mL
Now, use the constant to find the new volume:
Using Boyle’s Law
When atmospheric pressure = 14.9 psi, a sample of air has a volume of 30 mL. What will the volume of the air sample be when atmospheric pressure drops to 14.5 psi?
14.5psi V = 447 psi.mL
Now, use the constant to find the new volume:
mLpsi
mLpsi31
5.14447
V =×=
Using Boyle’s Law
We often see Boyle’s law written as P1V1 = P2V2
P1 = 14.9psi
V1 = 30mL
P2 = 14.5psi
V2 = ?
14.9psi 30mL = 14.5psi V2
V2 = 31mL
When atmospheric pressure = 14.9 psi, a sample of air has a volume of 30 mL. What will the volume of the air sample be when atmospheric pressure drops to 14.5 psi?
Using Boyle’s Law
In 1787, Jacques Charles discovered that the temperature and volume of a gas are
proportional
http://content.answers.com/main/content/wp/en-commons/thumb/b/b7/250px-Jacques-Charles_Dupont_de_L'Eure.jpg
In 1787, Jacques Charles discovered that the temperature and volume of a gas are
proportional
ice bath at 0C
In 1787, Jacques Charles discovered that the temperature and volume of a gas are
proportional
boiling water at 100C
20 mL of a gas at 0C will occupy 27.3 mL at 100C(as long as atmospheric pressure isn’t changed)
If temperature is in degrees Kelvin, we have the following:
ConstantT
V
This is known as Charles’ Law
We often see Charles’ law written as V1
T1
V2
T2
=
Using Charles’ Law
A sample of steam at 100C has a volume of 240 mL.What will the new volume be if the steam is cooled to
0C?
First, let’s convert our temps to Kelvin:
100C + 273 = 373K
A sample of steam at 100C has a volume of 240 mL.What will the new volume be if the steam is cooled to
0C?
First, let’s convert our temps to Kelvin:
100C + 273 = 373K
0C + 273 = 273K
Using Charles’ Law
A sample of steam at 100C has a volume of 240 mL.What will the new volume be if the steam is cooled to
0C?
First, let’s convert our temps to Kelvin:
100C + 273 = 373K
0C + 273 = 273KV1 = 240 mL
T1 = 373K
V2 = ?
T2 = 273K
V2 = 176 mL 240 mL
373K
V2
273K=
Using Charles’ Law
Combined Gas Law
• Derived from a combination of Boyle’s law and Charles’s law
• Change involving volume, pressure, and temperature simultaneously
Using the Combined Gas Law
• Calculate the volume of N2 resulting when 0.100 L of the gas is heated from 300. K to 350. K at 1.00 atm
• What do we know?– Pi = 1.00 atm Pf = 1.00 atm– Vi = 0.100 L Vf = ? L– Ti = 300. K Tf = 350. K
• Vf = ViTf / Ti this is valid as Pi = Pf
• Vf = (0.100 L)(350. K) / 300. K = 0.117 L
Many of the “most important” gases aren’t pure, but are actually
mixtures.
What is the composition of air?
780,810 N2 molecules
209,480 O2 molecules
9,340 Ar atoms
345 CO2 molecules
18 Ne atoms
5 He atoms
2 CH4 molecules
This is only true of dry, nonpolluted air.
For every 1,000,000 “air” molecules, . . .
What is the composition of air?
CO molecules NO molecules NO2 moleculesSO2 moleculesO3 molecules
In urban areas, the following pollutant molecules can be fairly abundant:
http://www.photo.net/photo/pcd0222/los-angeles-downtown-45.4.jpg
http://www5.worldisround.com/photos/5/282/505_o.jpg
Costa Rican rainforest
Consider a Rain Forest in Belize.
http://www5.worldisround.com/photos/5/282/505_o.jpg
At 86F and 95% humidity, we have:
Costa Rican rainforest
749,730 N2 molecules
201,140 O2 molecules
8,970 Ar atoms
330 CO2 molecules
17 Ne atoms
3 He atoms
39,810 H2O molecules
Water can be the 3rd most
abundant gas in air!
Consider a Rain Forest in Belize.
http://salegos-scar.montana.edu/images/Vostok%20Station.JPG
The amount of H2O in air is highly dependent on weather and geography.
Consider Vostok, Antarctica:
http://salegos-scar.montana.edu/images/Vostok%20Station.JPG
The amount of H2O in air is highly dependent on weather and geography.
At -76F and 34% humidity, we have:
780,810 N2 molecules
209,480 O2 molecules
345 CO2 molecules
18 Ne atoms
4 He atoms
3 H2O molecules
9,340 Ar atoms
Consider Vostok, Antarctica:
http://salegos-scar.montana.edu/images/Vostok%20Station.JPG
The amount of H2O in air is highly dependent on weather and geography.
Whether a gas is pure or a mixture, it still obeys Boyle’s law and Charles’ law
However, in a mixture of gases, the total pressure equals the sum of the pressures
due to each component
Why should you care?
Breathing air that is roughly 20% O2 means
that 80% of the molecular collisions in your lungs are useless.
Breathing 100% O2 increases the “partial
pressure” of O2
Liquid Properties
Liquids are . . .
•Not compressible
•Not organized
Viscosity
Liquids have . . .
Surface Tension
Vapor Pressure
Density
The Properties of Most Liquids Can be Rationalized
in Terms of Their Intermolecular Forces
Liquids have a surface tension (an edge effect)
Compare the attractive forces these molecules
have for their neighbors!
Liquids have a “Skin”!
Because it can hydrogen-bond, water’s skin is particularly tough!
Liquids have a “Skin”!
Liquids with weak intermolecular attractive forces have less surface tension.
Liquids have a “Skin”!
Water’s high surface tension causes it to “bead up” into large drops.
Liquids with weak intermolecular attractive forces have smaller drops.
Liquids have a viscosity
Which pours more easily, a jar of marbles
or a jar of gummy bears?
Liquids have a viscosity
Which pours more easily, gummy bears or
gummy worms?
Liquids have a viscosity
Long, flexible molecules with strong
intermolecular forces are most viscous.
Liquids have a vapor pressure
What happens when a liquid is poured into a perfectly empty container and the container is sealed?
Liquids have a vapor pressure
Some of the molecules at the surface evaporate.
Liquids have a vapor pressure
But the number of gas molecules only increases to a point.
Liquids have a vapor pressure
Some of the gas molecules bump backinto the liquid layer, slow down, and “re-stick”.
Liquids have a vapor pressure
When the number leaving the liquid equals the number re-entering the liquid, we have an “equilibrium”.
Liquids have a vapor pressure
When equilibrium is reached, molecules with strong intermolecular attractive forces look like this.
Liquids have a vapor pressure
When equilibrium is reached, molecules with weak intermolecular attractive forces look like this.
What is melting? What is subliming?
“Deposition” is the opposite of sublimation.