Transcript chapter 2a notes

Chapter 2
The Chemistry of
Life
CHEMISTRY
• The study of the
composition and
properties of matter
and the energy
transformations that
accompany changes
in the basic
structure of matter
Matter
Anything that
occupies space and
has mass
Matter
• Three states
• Composed of
elements
–5 elements are
essential to life in
large amounts (C, H,
O, N, Ca).
–Table 2-1, page 33
Matter
• Elements combine
to form compounds.
–Compound: a
substance made up
of two or more
elements (e.g., H2O)
What is the common
name for the compound
C6H12O6?
1.
2.
3.
4.
5.
Alcohol
Sugar
Vinegar
Salt
Baking soda
Matter
• Elements combine
to form compounds.
–Compounds have
different properties
from the elements
that form them.
Matter
• Elements combine
to form compounds.
–Expressed by
molecular and
structural formulas
Changes
• Chemical changes
• Physical changes
Energy
The ability to do work
Energy
• Kinetic energy
–Energy of motion
• Potential energy
–Stored energy
Can potential energy be
converted into kinetic
energy?
1. Yes
2. No
Can kinetic energy be
converted into potential
energy?
1. Yes
2. No
Energy
Changes
• 1st law of
thermodynamics
–Energy is neither
created nor
destroyed.
Energy
Changes
• 2nd law of
thermodynamics
–Whenever energy
is used, some of it
is wasted.
–Law of
degeneration
Entropy
An increase in disorder
and loss of usable energy
Energy
• Kinetic energy
• Potential energy
• Kinetic molecular
energy
–ALL of the
molecules in
matter are moving.
Energy
• Kinetic energy
• Potential energy
• Kinetic molecular
energy
• Potential energy of
a molecule
Chemical
Reactions
• Endothermic
–Require or
absorb heat
• Exothermic
–Give off heat
Chemical
Reactions
• Activation energy
–The amount of
energy needed to
start a chemical
reaction
Chemical
Reactions
• Catalysts
–Affect the rate of a
reaction but are
not changed in
the reaction
Chemical
Reactions
A+B
catalyst X
C+D
Chemical
Reactions
• Enzymes
–Compounds that
serve as organic
catalysts
Solutions
Suspensions
Colloids
Solution
• A homogeneous
mixture of one or
more substances in
another substance
• Solute (dissolved)
• Solvent (dissolver)
Suspension
• A substance in
which the particles
are mixed but are
not dissolved and
will settle out over
time
Colloid
• A mixture of fine
particles that do not
dissolve but also do
not settle out quickly
• Gel phase (semisolid)
& sol phase (fluid)
• Reversible &
nonreversible
Diffusion
Net movement of molecules
from an area of higher
concentration to an area of
lower concentration
Will diffusion eventually
stop, or will it continue
indefinitely?
1. It will stop.
2. It will continue.
Diffusion
• Kinetic molecular
energy is the driving
force behind
diffusion.
Diffusion
• Concentration
gradient
–Difference between
the numbers of 1
type of molecule in
2 adjacent areas
• Diffusion pressure
Osmosis
The diffusion of water
through a semipermeable
membrane
Will equilibrium ever be
reached in osmosis?
1. Yes
2. No