II CHEMISTRY
A. – Composition Of Matter
1. Matter – anything that occupies space and has mass.
a. Mass is the quantity of matter an object has.
b. Mass and weight are NOT the same – the pull of gravity on an
object is what fives an object the property of weight.
c. Biologists study chemistry because all living things are made
of the same kinds of matter that make up nonliving things.
2. Elements – pure substances that cannot be broken down chemically
into simpler kinds of matter.
a. 118 elements on the periodic table.
1. <30 are vital to living organisms.
2. >90 of the mass of all kinds of living things are
composed of: Nitrogen, Oxygen, Carbon, Hydrogen,
Phosphorus, and Sulfur.
b. A chemical symbol consists of one or two letters of the
element’s name. Some element names branch off of Latin; for
example, Aurum and Ferrum.
3. Atoms – the simplest particle of an element that retains all the
properties of that element.
a. Masses of atoms are measured in Atomic Units (au). Protons
and Neutrons both equal 1 au while an electron is considered
insignificant.
b. Parts Of The Atom
1. Nucleus – the central core of the atom; consisting of
two kinds of particles.
2. Proton – one of the two varieties of particles present
within the nucleus with a positive charge.
3. Neutron – one of the two varieties of particles present
within the nucleus with a neutral charge.
4. Electron – a small, negatively charged particle. In a
normal atom, the number of protons is balanced by the
number of electrons to make a net electrical charge of
zero.
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c. Atomic Number – the number of protons in an atom. All atoms
of the same element have the same number of protons. If the
number of protons were to change, the atom would become
that of a different element.
d. The Energy Levels
1. Energy level “K” can contain up to two electrons and is the
closest to the nucleus.
2. Energy level “L” is the second energy shell and can contain
up to eight electrons.
3. Energy level “M” is the third shell from the nucleus and
can contain up to eight numbers. In the event that “M” is full,
more shells are introduced, each being named according to
the alphabet. Shell “N” can contain up to 18 electrons.
e. Electrons furthest away from the nucleus have more energy
than those closer.
4. Compound – a pure substance that is made up of atoms of two or more
elements.
a. Most elements do not exist by themselves, but combine with
other elements.
b. Physical and chemical properties of a compound defer from the
original characteristics of the elements composing it. For
example, H2 and O exist as gasses but water is a liquid.
c. Chemical Reactions – a combination between elements
ultimately resulting in atomic stability. During a reaction,
chemical bonds are broken.
d. Molecule – the smallest unit of a substance that keeps all of the
physical and chemical properties of that substance. They are
composed of at least two covalently bonded atoms.
e. Energy Reactions in Animals
1. Plants and animals both store glucose. Plants store it as
starch, while animals store it as glycogen.
2. Hydrolysis – the process of breaking down
hydrocarbons for energy.
3. Nucleic acids such as DNA are composed of:
i. Thymine
ii. Adenine
iii. Cytosine
iv. Guanine
4. Unsaturated fats are more reactive than saturated fats as
their molecular structure allows for enzymes to break
them down more efficiently.
f. Forms of Bonds
1. Covalent Bond – a form of bond between atoms that forms
when atoms share one or more pair of electrons. When two
atoms of a nonmetal bond, a large amount of energy are
needed for either atom to lose an electron. Instead, they
share the needed electron
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2. Ionic Bonds – a bond that forms when electrons are
transferred from one atom to another atom. During ionic
bonding, one or more valence electrons are transferred from
one atom to another.
B. Energy
1. Energy and Matter
a. Energy – the ability to do work and cause change. Energy can
be converted from one form of energy to another, such as in a
light bulb.
b. Chemical energy, thermal energy, and mechanical energy are
all vital to the internal wellbeing of an organism.
c. Free Energy – the energy in a system that is available for work.
In a cell, free energy is the energy available to fuel cell
processes.
d. All atoms are in a state of constant motion. The precise amount
of motion between molecules determines the state of matter.
e. States of Matter
1. Solid – particles are tightly linked together in a definite
shape and volume and vibrate in place.
2. Liquid – particles are not as tightly linked together as
in a solid. A liquid has a definite volume but a shape
that varies.
3. Gas – particles of a gas have little or no attraction. A
gas has no definite shape and volume and fills to
completely encompass all available space.
2. Energy And Chemical Reactions
a. Reactants – the chemicals or elements being reacted with each
other to produce an outcome.
b. Products – the result of a reaction.
c. The number of each kind of atom must be the same on either
side of the
, as matter cannot be created or destroyed.
d. Most of the energy our bodies use comes from sugars from the
food we eat. To create energy, sugars are broken down to
carbon dioxide and water. The process results in the creation
of free energy.
e. Energy Transfer
1. Exergonic Reactions – reactions resulting in the release
of free energy.
2. Endergonic Reactions – reactions resulting in the
absorbance of free energy.
f. Activation Energy – the energy required to start Exergonic and
Endergonic reactions.
g. Catalysts – a chemical substance that reduces the amount of
activation energy needed for a reaction to occur.
h. Enzymes – an important class of catalysts present within the
cells of many living things.
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i. Reaction-Oxidation Reactions
1. Redox Reactions – reactions during which electrons are
transferred between atoms.
2. Oxidation Reaction – a reaction during which a
reactant loses one or more electrons, becoming positive
in charge.
3. Reduction Reaction – a reaction during which a
reactant gains one or more electrons, becoming
negative in charge.
C. Solutions
1. Describing Solutions
a. Solutions:
1. Solution – a mixture that appears to be a single substance
but is actually a mixture. A solution must be composed of
substances that are in the same phase (combining two or
more liquid/gases). Solutions have the same appearance and
properties throughout the mixture.
2. Solute – the substance that is dissolved into the mixture
(such as adding a spoonful of sugar to a cup of tea).
3. Solvent – the substance in which the solute is dissolved in
(the cup of tea). In order for the solute to be able to dissolve
into the solvent, it must be soluble.
b. Concentration – the measure of the amount of solute dissolved into
the solvent. Expressed in g/mL.
c. Aqueous Solution – solutions in which water is the solvent.
They are very important to living things. Examples include sea
water, intracellular fluid, and tea.
2. Acids And Bases
a. In water, the force of attraction between molecules that the
oxygen atom can remove a hydrogen atom from another water
molecule.
b. Disassociation – the breaking apart of a water molecule into
two ions of opposite charge.
H2O ↔ H+ + OHc.
In the above equation:
1. OH- is the Hydroxide Ion.
2. H+ can react with other water molecules through this
equation:
H+ + H2O ↔ H3O+
3. H3O+ is known as the Hydronium Ion.
d. Acidity or alkalinity is a measure of the relative amounts of
hydroxide ions and hydronium ions dissolved into a solution.
e. Relationship Between Hydroxide And Hydronium Ions
1. If the number of hydroxide ions in a solution equals the
number of hydroxide ions, the solution is neutral.
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2. If the number of hydronium atoms in a solution is
greater, the solution is an acid.
3. If the number of hydroxide atoms in a solution is
greater, the solution is a base. The word alkaline refers
to bases
f. pH Scale – a scale for comparing the relative concentrations of
hydroxide and hydronium ions in a solution. It ranges from 0 to
14; 0 being the most acidic and 14 being the most alkaline.
g. Buffers – chemical substances that neutralize small amounts of
either an acid or a base added to a substance.