Download Notes ch 2 the nature of matter

Chapter 2
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Atoms are the basic unit of matter.
Atoms are made of protons, neutrons and
electrons.
 Protons are positively (+) charged and found in
the nucleus.
 Neutrons are neutrally (0) charged and found in
the nucleus.
 Electrons are negatively (-) charged and are found
outside the nucleus.
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Elements are pure substances that contain
only one kind of atom.
Isotopes differ in the number of neutrons, but
have the same number of protons and
electrons.
Section 2-1
Nonradioactive carbon-12
Nonradioactive carbon-13
6 electrons
6 protons
6 neutrons
6 electrons
6 protons
7 neutrons
Radioactive carbon-14
6 electrons
6 protons
8 neutrons
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Compounds are formed be the chemical
bonding of 2 or more kinds of elements or
atoms.
Symbols and subscripts are used to show
compounds.
 H2O – Symbols are used to represent the
elements in the compounds. Subscripts show how
many atoms of that element are present.
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The main types of bonds are ionic and
covalent.
Ionic bonds occur when 1 or more electrons
are transferred from one atom to another.
Covalent bonds occur when 2 atoms share
one or more pairs of electrons.
Section 2-1
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Protons +11
Electrons -10
Charge +1
Protons +17
Electrons -18
Charge -1
Transfer
of electron
Protons +11
Electrons -11
Charge 0
Protons +17
Electrons -17
Charge 0
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pH is a measure of the hydrogen ions in the
solution.
The scale is exponential- a pH of 3 is 10X
more acidic than a pH of 4.
Acids have more hydrogen ions.
Bases have fewer hydrogen ions, but more
OH- (Hydroxide) ions
pH Scale
Increasingly Basic
Oven cleaner
Neutral
Increasingly Acidic
pH is a
measure of
hydrogen
ions in
solution
Bleach
Ammonia solution
Soap
Sea water
Human blood
Pure water
Milk
Normal
rainfall
Acid rain
Tomato
juice
Lemon juice
Stomach acid
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Polar molecules have a slightly positive end
and a slightly negative end.
This causes hydrogen bonds to form. The (+)
end of one molecule is attracted to the (-) end
of another molecule.
 Cohesion is the attraction of molecules of the
same substance.
 Adhesion is the attraction of molecules of
different substances.
Section 2-2
ClCl-
Na+
Na+
Water
Water
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Carbon can form 4 covalent bonds either with
other carbon atoms or other molecules.
These bonds can be single, double or triple.
This accounts for the 4 major
macromolecules: carbohydrates, lipids,
nucleic acids and proteins.
Carbon
Compounds
include
Go to
Section:
Carbohydrates
Lipids
Nucleic acids
Proteins
that consist of
that consist of
that consist of
that consist of
Sugars and
starches
Fats and oils
Nucleotides
Amino Acids
which contain
which contain
which contain
which contain
Carbon,
hydrogen,
oxygen
Carbon,
hydrogen,
oxygen
Carbon,hydrogen,
oxygen, nitrogen,
phosphorus
Carbon,
hydrogen,oxygen,
nitrogen,
Starch
Glucose
Section 2-3
Figure 2-16 Amino
Acids
Section 2-3
Amino group
Carboxyl group
General structure
Alanine
Serine
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Enzymes are proteins that act as catalysts.
Catalysts speed up the rate of the reaction by
lowering the activation energy.
They have special shapes that fit the
substrates.
Substrates are the reactants in the reaction.
Amino
acids
Section 2-3
Reaction pathway
without enzyme
Activation energy
without enzyme
Reactants
Reaction pathway
with enzyme
Activation
energy
with enzyme
Products
Figure 2-21 Enzyme Action
Section 2-4
Enzyme
(hexokinase)
Glucose
Substrates
Products
ADP
Glucose-6phosphate
Products
are released
ATP
Active site
Enzyme-substrate
complex
Substrates
are converted
into products
Go to
Section:
Substrates
bind to
enzyme
Figure 2-21 Enzyme Action
Section 2-4
Enzyme
(hexokinase)
Glucose
Substrates
Products
ADP
Glucose-6phosphate
Products
are released
ATP
Active site
Enzyme-substrate
complex
Substrates
are converted
into products
Go to
Section:
Substrates
bind to
enzyme
Figure 2-21 Enzyme Action
Section 2-4
Enzyme
(hexokinase)
Glucose
Substrates
Products
ADP
Glucose-6phosphate
Products
are released
ATP
Active site
Enzyme-substrate
complex
Substrates
are converted
into products
Go to
Section:
Substrates
bind to
enzyme
Figure 2-21 Enzyme Action
Section 2-4
Enzyme
(hexokinase)
Glucose
Substrates
Products
ADP
Glucose-6phosphate
Products
are released
ATP
Active site
Enzyme-substrate
complex
Substrates
are converted
into products
Go to
Section:
Substrates
bind to
enzyme