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Chemistry
What is Chemistry?
The science dealing with the structure
and composition of substances, the
changes in composition, and the
mechanisms by which the changes
occur.
 The study of matter and its interactions.

What is matter?
Anything that occupies space and has
mass.
 Everything!

Changes in composition

What changes matter?
Nature
 External force

Most changes in matter accompany
energy.
 What does chemistry and these changes
in composition have to do with
respiratory therapy?

Definitions

Atom


The smallest unit of an element that can
exist either alone or in combination with
atoms of the same or different elements.
Consist of protons, neutrons, and electrons.
Element

A substance that cannot be further
decomposed by ordinary chemical means, a
substance in which all the atoms have the
same number of protons.
Definitions Cont.

Molecule

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The smallest chemical unit of a substance that is
capable of stable existence.
Molecules are made up of one or more atoms. If
they contain more than one atom, the atoms can be
the same (an oxygen molecule has two oxygen
atoms) or different (a water molecule has two
hydrogen atoms and one oxygen atom). Biological
molecules, such as proteins and DNA, can be
made up of many thousands of atoms.
Definitions Cont.

Compound

A chemical compound is a chemical
substance formed from two or more
elements, with a fixed ratio determining the
composition. For example, dihydrogen
monoxide (water) is a compound composed
of two hydrogen atoms for every oxygen
atom.
The Atom
The Atom
Nucleus
 Protons
 Neutrons
 Electrons
 What is a neutral atom?

Periodic table
Symbols
 Atomic numbers (# of protons)
 Mass numbers (protons & neutrons)
 Rows (Periods)
 Columns (Groups or Families)

Periodic table

Metals
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Nonmetals
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Alkali Metal Elements
Alkali Earth Elements
Halogen Elements
Noble Gas Elements
Metalloids


Transition Metal Elements
Main Group Elements
Electrons
Excited state
 Ground state
 Energy levels

Electron Configuration
Quantum Atomic Model
 Bohr Model
 Lewis Electron Dot Model

Electrons and Energy levels
How many are there?
 How many electrons can they hold?
 How do the electrons fill the levels?

Shell (energy levels 1-7)
 Sub-shell (s,p,d,f)
 Orbital

Quantum Atomic Model
Quantum Atomic Model
Bohr Model
Lewis Electron Dot Model
Valence Electrons
Combining capacity.
 Number given to an atom that indicates
it’s tendency to loose or gain electrons in
a chemical reaction.
 How many electrons are in an atom’s
outer shell to be considered full?

Periodic table short cuts
Periods = # of shells each elements has
 Groups = # of electrons in outer shell
(valence electrons)

Stable atoms
Atoms are said to be stable when their
outer most shell is full.
 Which elements are stable on the
periodic chart?
 Elements who do not have 8 electrons in
their outer shell are constantly looking for
a way to be stable.

How do atoms fill their outer
levels?
Take electron(s) from another atom.
 Give electron(s) to another atom.
 Share electron(s) with another atom.

Ions
When atoms give or take electrons it
changes their neutrality.
 Ion = an atom that has an electrical
charge as a result of gaining or losing
electrons.
 Cation = positively charges ion
 Anion = negatively charged ion.

Types of bonds

Ionic = a bond that has formed as a result of
the atoms in the compound gaining/losing
electrons.
 Covalent = a bond that has formed by the
sharing of electrons between the various
atoms in the compound.

Hydrogen (Polar covalent) = occur when a
Hydrogen atom is covalently bonded to a Nitrogen
or Oxygen atom and is attracted to another
Nitrogen or Oxygen atom.
Isotopes
Atoms of an element having the same
chemical properties but different atomic
weights.
 So if all atoms of a certain element have
the same number of protons, what
changes the atomic weight?

Radioactive Isotopes
Used in nuclear medicine
 Very unstable
 We manipulate their nuclear structure.
 They emit high energy radiation.
 They can be detected by instruments to
evaluate the function of body parts.
 They do damage cells.

Balancing Equations
The substances that are starting material
in a chemical reaction are REACTANTS.
 The substances produced as a result of
the reaction are called PRODUCTS.
 Balancing a chemical equation consist of
make your REACTANTS and Products
equal.

Balancing Equations

Is this balanced?

H + Cl² → HCl

NO WAY!

What would a balanced equation look
like

2H + Cl² → 2HCl
Balancing Equations

Difference between a subscript and a
coefficient.
Subscript (N²) Can NEVER be changed!
 Coefficient (2N) Can always be changed!

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Coefficients need to be REDUCED aka
SMALL!
Organic & Inorganic Compounds

Organic compounds are molecules that
contain carbon to carbon bonds and/or carbon
to hydrogen bonds.
 Inorganic compounds do not contain carbon.
Inorganic compounds come principally from
mineral sources of non-biological origin.
Inorganic compounds often includes all metalcontaining compounds, even those found in
living systems.
Inorganic Compounds
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Types of inorganic compounds
Major branches of inorganic compound groups
include:
Minerals, such as salt, asbestos, silicates, ...
Metals and their alloys, like iron, copper,
aluminum, brass, bronze, ...
Compounds involving non-metallic elements,
like silicon, phosphorus, chlorine, oxygen, for
example water
Metal complexes
Inorganic Compounds

What do you think is the most abundant
inorganic substance in the human body?
Wonderful Water!

Absorbs and releases heat very slowly
 Requires a large amount of heat to change
from a liquid to a gas.
 Serves as lubricant
 It participates in chemical reactions


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Hydrolysis
Dehydration synthesis
Is a great solvent!
Solution

A solution (salt water) is composed of a
solvent (water) and a solute (salt).
Organic Compounds
Always contain carbon to carbon and/or
carbon to hydrogen bonds.
 Most organic compounds are bound by
covalent bonds containing hydrogen.

4 major organic compounds found in
the body
Carbohydrates
 Lipids
 Proteins
 Nucleic Acids

Carbohydrates
Carbohydrates are the bodies most
readily available source of energy.
 The building blocks are
monosaccharides.
 Carbohydrates are divided into 3 main
groups based on size.

Monosaccharides
 Disaccharides
 Polysaccharides

Lipids
Lipids protect and insulate the body.
 Lipids are an inefficient source of energy.
 Fats are lipids that are solid @ room
temperature, and oils are lipids that are
liquid @ room temperature.
 The building blocks are triglycerides,
which are made up by one glycerol to
three fatty acids.

Lipids cont.

There are three types of lipids found in
the body.

Triglycerides
Saturated fat
 Monounsaturated
 Polyunsaturated
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Phospholipids
 Steroids
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Cholesterol
Proteins

Proteins have structural and functional
properties in the body.
Proteins cont.
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Structural
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Help form structures (e.g. collagen)
Hold body tissues together
Form a fibrous water-proof layer on skin (keratin)
Functional

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Participate in chemical processes such as hormones,
growth factors & cell membranes.
Help reactions occur BUT are not reactants
They are chemical catalyst called ENZYMES, which speed
up reactions.
Each enzyme has a shape that “fits” into the molecules
involved in a reaction with the “Lock and Key Method”.
Proteins cont.
The building blocks are amino acids.
 When two or more amino acids combine
the are bonded by peptide bonds.

Nucleic Acids
Nucleic acids are extremely large
organic molecules containing carbon,
hydrogen, oxygen, nitrogen, and
phosphorus.
 The building blocks are nucleotides.
 There are two principle kinds:

DNA (deoxyribonucleic acid)
 RNA (ribonucleic acid)
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DNA (deoxyribonucleic acid)

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Double helix
The uprights of the ladder consist of
alternating phosphate groups and the
deoxyribose portions (sugar) of the
nucleotides.
 The rungs on the ladder consist of alternating
paired nitrogenous bases.
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Adenine paired with Thymine
Cytosine paired with Guanine
About 1000 rungs of DNA nucleotides
comprise a gene.
RNA (ribonucleic acid)
Single strand
 RNA’s sugar ribose does not contain
oxygen.
 RNA does not contain the nitrogenous
base thymine, instead it contains Uracil.
 RNA has a specific role to perform with
DNA in protein synthesis.

Acids, Bases, and Salts…Oh my

Acids, bases, and salts are considered
inorganic compounds.
Acids, Bases, and Salts…Oh my
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Acid
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typically water-soluble, when the acid disassociates
(is dissolved) in water it produces an excess of
hydrogen ions (H+)
sour-tasting chemical compound
In common usage an acid is any substance that,
when dissolved in water, gives a solution a pH of
less than 7.
An acid reacts with a base in a neutralization
reaction to form a salt.
Acids, Bases, and Salts…Oh my

Base
typically water-soluble, when the base
disassociates (is dissolved) in water it
produces an excess of hydroxyl ions (OH-).
 In common usage a base is any substance
that, when dissolved in water, gives a
solution with a pH greater than 7.
 A base reacts with an acid in a
neutralization reaction to form a salt.

Acids, Bases, and Salts…Oh my

Salt
salt is a term used for ionic compounds
composed of positively charged cations and
negatively charged anions, so that the
product is neutral and without a net charge.
 An example is the acid (chlorine) mixing
with a base (sodium) which yields a salt
(Na+Cl-).

pH
definition of pH is the negative
logarithmic scale that measures the
hydrogen ion concentration.
 The log is a base of 10.
 Meaning 6 is 10x different than 7, or 5 is
100x different than 7.

pH scale

The acidity or alkalinity (base) of a solution is
measured on a scale of values called the pH
scale.
 The values on the pH scale range from 0-14
 0 indicates the most acidic (lowest) pH


More H+ than OH-
14 indicates the most alkaline (highest) pH

More OH- than H+
pH
pH cont.
A solution with a pH of 7.0 is neutral
because it contains the same number of
hydrogen ions (H+) as hydroxyl ions
(OH-).
 Pure water has a pH of 7.0
 The bodies neutral pH is slightly alkaline.
 Normal for the body is 7.35-7.45

pH cont.
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How do we get the pH of a substance?
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Is it measured or calculated?
It is all in the term pH
p = power of
 H = hydrogen ions
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It is calculated by the HendersonHassalbach equation.
Henderson-Hassalbach equation

pH= pK + log of bicarbonate/carbonic acid

pH= pK + log (HCO3/H2CO3)
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pK= disassociation constant
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Changes depending on the acid
We use 6.1 for H2CO3-
Henderson-Hassalbach equation
If the ratio of bicarb : carbonic acid is
20:1 it will yield a pH of 7.4 (normal)
 So what will a bicarb: carbonic ratio of
20:5 yield (acidic or alkaline)?
 What about 15:1.8
 And
24:1.38

Henderson-Hassalbach equation
As the HCO3:H2CO3 ratio increase from
20:1 to 25:1 the pH increases and
becomes more alkaline.
 As the HCO3:H2CO3 ratio decreases
from 20:1 to 15:1 the pH decreases and
becomes more acidic.

pH
How do you think the body maintains the
20:1 ratio?
 It is maintained by three systems.

Respiratory system
 Urinary system (metabolic)
 Chemical buffer system
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This is a CONSTANT process!
Respiratory system
The respiratory system maintains the
acid-base balance by increasing or
decreasing your respiratory rate.
 When we breathe out what gas are we
exhaling?
 Is that an acid or a base?

Respiratory system
So if we increase our rate we are getting
rid of acid, or causing our blood to be
more alkaline.
 If we decrease our rate we are holding
onto acid, or causing our blood to be
more acidic.

Urinary system (metabolic)
We can maintain acid-base balance by
urinating more base or holding onto it.
 If a patients urine is very acidic their
body is holding onto the HCO3, making
the blood more alkaline.
 If a patients urine is very alkaline their
body is getting rid of the HCO3, making
the blood more acidic.

Chemical Buffer Systems
Strong Acid-disassociates completely to
H+ ions.
 Weak Acid-partially disassociates to H+
ions.
 Strong Base-disassociates completely to
OH- ions.
 Weak Base-partially disassociates to
OH- ions.

Chemical Buffer Systems
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Buffer
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A chemical substance that prevents a sharp
change in the pH of a fluid when an acid or
base is added to it.
Buffer pairs
Chemical substances that are paired to
buffer both acids and bases.
 Common example is NaHCO3 & H2CO3

NaHCO3 & H2CO3 buffer pair
If HCl, a very strong acid, was exposed
to your bloodstream without being
buffered it would cause harm.
 When HCl walks up to the NaHCO3 &
H2CO3 buffer pair who will it choose to
bind with?

NaHCO3 OR
 H2CO3

NaHCO3 & H2CO3 buffer pair
NaHCO3!
 When HCl (strong acid) pairs with
NaHCO3(buffer) the product is NaCl
(salt) & H2CO3(weak acid).

NaHCO3 & H2CO3 buffer pair

On the other hand if a strong base, such
as NaOH, was added to the NaHCO3 &
H2CO3 buffer pair which buffer would it
pick?
NaHCO3 OR
 H2CO3

NaHCO3 & H2CO3 buffer pair
H2CO3!
 When NaOH (strong base) pairs with
H2CO3(buffer) the product is H2O
(water) & NaHCO3(weak base).
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STUDY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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