Transcript Basic Chemistry and Water Chemistry

Warm up:
 When cells divide and become larger, this
process is found under what 2 characteristics
of life?
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Reproduction
Growth
 Breathing is a form of what characteristic of
life:
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Need for energy
 Heartbeat increasing under stress is what
characteristic of life?
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Response to stimuli
Water intro video
 https://www.youtube.com/watch?v=HVT3Y3_
gHGg
Chapter 2 Biochemistry
Basic Chemistry and Water Chemistry
Basic Chemistry – Matter, Elements,
and Compounds
 MATTER: anything that takes up space
and has mass.
 ELEMENT: a substance that cannot be
broken down by ordinary means. The
material making up matter.
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There are 92 naturally occurring elements,
of these 25 are essential to life. 4 of these
make up 96% of living matter (Carbon,
Hydrogen, Oxygen, and Nitrogen).
 Small units of matter are called atoms .
 Protons(+), neutrons(0), and electrons(-),
are the subunits of atoms.
 Protons = Atomic Number
 Electrons = Atomic Number unless there
is a charge.
 Neutrons = Atomic Mass (larger number) –
Atomic number (smaller number)
 COMPOUND: more than one element (more
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than one capital letter). Formula EX: H2O or
C6H12O6
ISOTOPES: Different atomic forms caused by
varying the number of neutrons.
Example: Normal carbon is C-12, carbon
isotope is C-14.
The number is the mass of the isotope.
Some isotopes are radioactive, they undergo a
transformation to gain a stable condition. This
transformation is called the half-life of the
isotope.
Protons and Neutrons make up the nucleus of
the atom. Electrons orbit the nucleus.
Chemical Bonds
 Covalent Bond: These
bonds are the strongest
of the bonds. They are
formed by the sharing
of the valence
electrons.
 Ionic Bond: These
bonds are formed by
the taking of electrons.
Anion: negative ion, Cland (OH) Cation:
positive ion, Na+ and
(NH4)+.
 Hydrogen Bond: This bond is formed when hydrogen
that is covalently bonded to an electronegative atom
is attracted to another electronegative atom on
another molecule.
Chemical Reactions
 The combination of 2 or more elements
forming a different product or products.
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Each reaction contains reactants and
products. The reactants are written on the left
side of the equation, while the products are
written on the right side.
The reactants and products must contain the
same number of atoms making the reaction
balanced.
Example:
Water Chemistry
 Water is important to life.
 Because of the unique
properties of water, life
exists in its present form
on this planet.
 Due to the polar covalent
bonds that hold a water
molecule together,
hydrogen bonds form
where the negatively
charged Oxygen and the
positively charged
Hydrogen are located.
The results of these bonds are as
follows (10):
 1. Cohesion: is the sticking together of
similar molecules. Water is very cohesive.
This allows water to be pulled along a
pathway with relative ease.
 2. Surface Tension:
cohesion allows water to
pull together and form
droplets or form an
interface between it and
other surfaces. The
measure of how hard it is
to break this interface is
its surface tension.
 Water allows materials to
rest upon it if the surface
tension is not broken.
 3. Adhesion: The sticking of one substance to
another. Water is a good adhesive. It will cling
on to many objects and act as a glue.
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Capillary Action is an example of cohesion and
adhesion working together to move water up a
thin tube.
 4. High Specific Heat: Specific heat of a
substance is the heat needed (gained or
lost) to change the temperature of 1 g. of a
substance 1 degree Celsius.
 5. High Heat of Vaporization: Water must
absorb a certain amount of additional heat
to change from a liquid into a gas. This
extra heat is called heat of vaporization.
 6. Freezing and Expansion of Water: Water
is most dense at 4 degrees C. At 0 degrees
C. it is 10% less dense. Ice floats because
maximum Hydrogen bonding occurs at 0
degrees C.
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Ice (solid water) is less dense than liquid
water, so ice floats, preventing lakes and
oceans from freezing solid. The ice at the
top of the water insulates the liquid below.
 7. Versatile Solvent:
Water is a major solvent
in nature. When water and
another substance is
mixed the resulting
solution is called an
aqueous solution.
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Any solution contains
the following parts:
Solute (what's being
dissolved) + Solvent (
what is doing the
dissolving) = Solution.
 8. Diffusion : Occurs in cells when
substances (oxygen, carbon dioxide, salts,
sugars, amino acids) which are dissolved in
water move from an area of higher
concentration to an area of lower
concentration.
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9. Osmosis: The movement of water molecules
through a semi-permeable membrane from an area of
greater water concentration to an area of lesser water
concentration.
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10. pH: Refers to the
dissociation of water
molecules.
pH Scale:
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The pH scale goes from 0 
14.
The pH of pure water is 7
(neutral)
Substances added to water
can lower or raise the pH.
A solution with a pH below 7
is acidic.
A solution with a pH above 7
is basic (alkaline)
 Buffers: A buffer is a mixture of chemicals
that keeps the pH of a solution relatively
constant. A buffer system acts by taking
up or releasing H ions. They add H ions
when a solution becomes basic (higher
than 7) and they take H ions out of the
solution when the pH becomes acidic
(lower than 7).