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2.1 The nature of Matter
2.2 Properties of Water
2.3 Carbon Compounds
2.4 Chemical Reactions and enzymes
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An element is a substance that cannot be
broken down into simpler substances by
chemical or physical means
◦ Ex-anything on the periodic table ( oxygen, gold)
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An atom is the smallest particle of matter that
contains the characteristics of an element
◦ Atoms is composed of
 Nucleus at the center
 Protons(+) and Neutrons
 Around the Nucleus are
Electrons (-)
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The number of protons in the nucleus
of an atom is called the Atomic
Number
◦ Element is distinguished by the Atomic
number
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Electrons are located in regions called
Energy Levels
Atoms with the same number of
protons but different numbers of
neutrons are isotopes of an element
The Mass number of an atom is the
total mass of an atom (protons plus
neutrons
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Chemical combinations of the atoms of
elements are called Compounds
When an atom’s outermost energy level does
not contain the maximum number of
electrons, the atom is likely to form a
chemical bond with one or more other atoms
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An atom that has an electrical
charge because of a gain or loss
of one or more electron is called
an Ion
◦ Ionic bonds form between positive
and negative ions (Weak Bonds)
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Covalent bonds form when
atoms share electrons
Metallic bonds form when
electrons are shared by metal
bonds
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Pg 39 (1-5)
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A water molecule is Polar because there is an
uneven distribution of electrons between the
oxygen and hydrogen atoms.
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Due to these positive and negative charges,
molecules are attractive
◦ Cohesion- an attraction between molecules of the
same substance
◦ Adhesion- an attraction between molecules of
different substances
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A Mixture is material composed of two or more
elements or compounds that are physically
mixed but not chemically combined
When Kool-aid is evenly distributed
and dissolved in water it is a Solution
◦ Kool-aid = Solute
◦ Water = Solvent
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Mixtures of water and nondissolved substances
are known as Suspensions (sand in water)
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Chemists designed the pH Scale to indicate the
concentration of H+ ions in a solution
Scale goes from 0-14 with 7 being neutral (H20)
◦ Greater than 7 is a base
◦ Lower than 7 is an acid
◦ Scale is Logarithmic (acid of 4 is 10x acid of 5 pH)
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Acidic solutions contain higher concentration of
H+ ions than pure water
Basic or Alkaline solutions have a lower
concentration of H+ than water (so it takes H+)
Buffers helps solutions get closer to Neutral
◦ Water added to an acid or base neutralizes it
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Pg 43 (1-5)
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Large Carbon Molecules
◦ In many carbon compounds, the molecules are built
up from smaller, simpler molecules known as
monomers
◦ A polymer consists of repeated, linked monomers
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Carbohydrates- Organic compounds composed
of carbon, hydrogen, and oxygen
Monosaccharide (simple sugar)-A carbohydrate
monomer
 Compounds like this simple sugar, with a single chemical
formula but different forms, are called isomers. (Glucose,
Fructose, lactose)
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Disaccharide (double sugar)- 2 Monosaccharides
Polysaccharide (many sugars)- A complex
molecule of three or more monosaccharides
 Plants and animals will store glucose as a polysaccharide (Glycogen)
for quick energy use when needed.
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Proteins- Organic compounds
composed mainly of carbon,
hydrogen, oxygen and nitrogen
◦ The 20 different amino acids, the
monomer building blocks of proteins,
share a basic structure
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Amino acids are covalently
bonded by a peptide bondchains of amino acids are called
polypeptides
◦ Proteins are composed of one or
more polypeptides
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Lipids- Large, non-polar organic molecules
that do not dissolve in water
◦ Fatty Acids- Unbranched carbon chains that make
up most lipids
◦ One end of the fatty acid is hydrophillic (water
loving) while the other end is hydrophobic (water
fearing)
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Nucleic Acids- Very Large and complex
organic molecules that store important
information in the cell
 Both DNA and RNA are nucleic acid polymers, composed
of thousands of linked monomers called nucleotides.
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Pg 48 (1-5)
Review Tues
Ch 2 quiz Wed
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A Chemical reaction is a process that
changes, or transforms one set of chemicals
into another
◦ Chemicals that enter the reaction are Reactants
◦ Products are the chemicals that are produced
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Chemical reactions involve the change in
chemical bonds that join atoms in
compounds
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Chemical reactions that release energy
happen spontaneous, while reactions that
absorb energy will not occur without a source
of energy
Living organisms need energy to carry out all
of the chemical processes in their body
◦ This energy to start a chemical reaction is called the
Activation energy
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A Catalyst is a substance that speeds up the
rate of a chemical reaction by lowering the
activation energy
Enzymes are proteins that act as biological
catalysts (speed up reactions in cells)
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Enzymes work because they give a site for
reactants to go through a chemical reaction
The reactants of an enzyme-catalyzed
reactions are known as Substrate
Pg 53 (1-5)