Transcript Year in Review - Cobb Learning

EOC and FINAL EXAM
REVIEW
CHARACTERISTICS OF SCIENCE
• INDEPENDENT VARIABLE: the factor that the
scientist changes, also known as the manipulated
variable
• DEPENDENT VARIABLE: the factor that changes
because the independent variable changed, also
known as the responding variable
• CONTROL: an experiment run without a variable,
eliminates possibility of hidden variables
• REMINDER: when graphing your data, remember
DRY MIX
CHARACTERISTICS OF SCIENCE
• METRIC SYSTEM (INTERNATIONAL SYSTEM OF
UNITS)
• prefixes:
kilohectodekabasic unit (m, l, g)
decicentimilli-
CHARACTERISTICS OF SCIENCE
• SCIENTIFIC METHOD: step-by-step process by
which scientists do experiments and collect
data
• A step-by-step process insures accuracy and
allows other scientists to repeat the work
• Never test more than one variable at a time
• First form a hypothesis, then a theory, then a
law
MATTER
• ATOM: smallest particle of an element, cannot be
broken down into anything smaller and still be the
element
• Major subatomic particles:
proton – positively charged, in the nucleus
(causes the nucleus to be positive)
neutron – neutral, in the nucleus, largest mass
of any subatomic particle
electron – negative, in electron cloud, moves so
fast it is like it is everywhere at once, least mass of the
major subatomic particles
MATTER
• CURRENT ATOMIC MODEL:
Electron Cloud Model (Bohr, Schrodinger, Heisenberg):
electrons are in areas known as the electron cloud, within this
cloud there are 7 known energy levels, electrons can become
energized and move to a higher energy level but will fall back
to the original energy level when the energy is released
• PREVIOUS ATOMIC MODEL:
Bohr Model: believed electrons travel in set paths and that
they could jump between energy levels
• FIRST PROPOSED THE IDEA OF AN ATOM:
Democritus believed there was an indivisible particle that
he called an atom
MATTER
• ELEMENT: simplest substance on Earth,
cannot be broken down into a more simple
substance and still be the same element
• Type of element is determined by the proton
number. Change the number of protons,
change the element
• Elements are arranged by increasing atomic
mass on the Periodic Table (over 110
elements)
MATTER
• PERIODIC TABLE: properties change periodically as you
move from left to right across the table, developed by
Mendeleev
• Columns of elements are groups (1-18) and families
(Halogens, Noble Gases, etc.), all elements in a column
have the same number of valence electrons
• Rows of elements are periods (1-7), all elements in a
row have the same number of energy levels
• Metals are located left and center (exception: H), nonmetals are on the right, metalloids separate the metals
and non-metals
MATTER
• Octet rule: Elements bond in an effort to create an outermost
energy level that contains 8 valence electrons. This provides atomic
stability. (EXCEPTION: 1ST ENERGY LEVEL IS STABLE WITH 2
VALENCE ELECTRONS)
• Metals – tend to transfer their valence electrons to non-metals
• Non-Metals – tend to take valence electrons from metals or share
with another non-metal
• 3 Types of Bonds
– Covalent: prefix co- means to share, non-metal + non-metal
– Ionic: transfer of valence electrons creates positive and
negative ions, metal + non-metal
– Metallic: metals have freely moving valence electrons that
become part of the common electron sea, metal + metal
MATTER
• COVALENT COMPOUNDS: contain a covalent bond, name will
contain prefixes which note how many of each atom are present
• IONIC COMPOUNDS: contain an ionic bond that formed when the
metal transferred its valence electrons to the non-metal, positive
ion always comes first in the chemical formula and name
• Remember that the oxidation states within a molecule must add up
to equal zero. Insert subscripts to make the oxidation states
(bonding capacity) equal zero.
• If a metal has 2 valence electrons it wants to give them away. Its
oxidation state is 2+. If a non-metal has 7 valence electrons it wants
to take one. Its oxidation state is 1• 2+ and 1- do not equal zero, so you have to put a subscript of 2 on
the non-metal to make the oxidation states of this molecule equal
zero
MATTER
• LAW OF CONSERVATION OF MATTER: matter
cannot be created or destroyed, it can be
conserved and transformed
• During a chemical change, or chemical reaction,
all atoms must be accounted for
• Coefficients are inserted in chemical equations to
make sure all atoms are accounted for
• A chemical change, or chemical reaction, always
changes the identity of the matter
MATTER
• CATEGORIES OF MATTER:
Pure Substances: a substance that is made of
one type of particle
element – made of one type of atom
compound – made of one type of molecule
Mixtures: Made of multiple types of particles,
includes solutions, colloids, and suspensions
MATTER
• Mixtures: not a pure substance, made up of multiple
kids of particles, will be made of different kinds of
atoms and molecules that are not chemically bonded
• Types of Mixtures:
Homogeneous – looks uniform throughout,
includes solutions and colloids
Heterogeneous – does not look uniform
throughout, can see the different substances making it
up, includes suspensions
MATTER
• HOMOGENEOUS MIXTURES:
Solution - solute dissolves in the solvent, very
small particle size, does not settle or scatter
light, example: salt water
Colloid: intermediate to small particle size,
does not settle, does scatter light, example: mayo
• HETEROGENEOUS MIXTURES:
Suspension – large particle size, settles after
sitting, scatters light, example: oil/vinegar
dressing
MATTER
Types of Chemical Reactions
• Synthesis A + B  AB
• Decomposition AB  A + B
• Single Replacement A + BC  AB + C
• Double Replacement AB + CD  AC + BD
Reduction- Oxidation Reaction (redox): may be synthesis,
single or double replacement, occurs when electrons are
transferred, OIL RIG
Neutralization Reaction: Occurs between acids and
bases, results in the formation of water and a salt, usually
a double replacement reaction
MATTER
• State of Matter: the physical form in which the
matter exists
• State of matter is determined by the amount of
particle movement
• States: solid, liquid, gas, plasma, Bose-Einstein
condensate
• Matter can transition from one state to another.
The type of state change is determined by
whether energy is being added or removed from
the matter
MATTER
• STATE CHANGES:
Note: recombination = de-ionization
enthalpy = change in internal energy
MATTER
• Phase Change Diagram:
MATTER
• IDEAL GAS LAWS:
Charles’ Law- inverse relationship between volume
and pressure with a constant temperature.
Boyle’s Law- direct relationship between volume
and temperature with a constant pressure.
Gay-Lussac Law - is a special case of Charles’ Law.
This law only applies to ideal gases held at a
constant volume allowing only the pressure and
temperature to change.
MATTER
• HYDROCARBONS: molecules composed of
carbon, hydrogen, and oxygen
saturated – contains only single bonds
unsaturated – contains double and/or triple
bonds
aromatic – contains a
6-carbon benzene
ring with alternating
single and double bonds
MATTER
• Compounds: pure substances that are made of
one type of particle. That particle is a molecule.
All molecules of a particular compound look alike.
• Molecules: made up of 2 or more atoms that
have bonded chemically. If the molecules are
part of a compound, the atoms will be of
different elements
• Not all molecules are part of a compound.
Example: diatomic elements when found pure in
nature are bonded to another one of themselves
in a molecule
ENERGY
• ENERGY: THE ABILITY TO DO WORK
• Law of Conservation of Energy: energy cannot be
created or destroyed, it can be conserved and
transformed
• Energy Transformation: changes from one form
to another such as electrical energy becoming
light energy when a lamp is turned on. Every
time a transformation occurs some energy is
“lost” as thermal energy
• Energy Transference: energy is transferred from
one object to another
ENERGY
• MAJOR CATEGORIES OF ENERGY:
Kinetic: energy of motion
examples: electrical, light, sound, thermal
Potential: energy of position
examples: GPE, EPE, chemical, nuclear
Mechanical: total amount of PE and KE
• All types of energy can be transformed into
another type, some thermal energy will always be
produced during this transformation
ENERGY
• GRAVITATIONAL POTENTIAL ENERGY: energy an
object has because it was lifted against the pull of
gravity
• The amount of force needed to lift an object
against the pull of gravity is equal to its weight.
• On Earth gravity pulls with a force of 9.8 N for
every one kg of mass.
• To determine an object’s weight, multiply its
mass by 9.8. Units will be Newtons.
ENERGY
• HOOKE’S LAW: the force needed to extend or
compress a spring by some distance is
proportional to that distance, when the spring
is fully extended or fully compressed it has its
maximum PE
ENERGY
• ELECTRICITY: the movement of charges (usually
negative charges)
• Circuit: a closed loop through which charges can
flow
• The movement of charges along a wire creates a
magnetic field around the wire.
• The movement of a wire through a magnetic field
induces charges to flow in the wire. Charges will
continue to flow as long as the wire is moving in
and out of the magnetic field or the magnetic
field is moving around the wire
ENERGY
• SERIES CIRCUIT: only one path for the charges to follow
• PARALLEL CIRCUIT: multiple paths for
the charges to take
ENERGY
• LAW OF ELECTRIC CHARGES: opposite charges
attract, like charges repel
• ELECTROMAGNETIC FORCE: the push or pull
that exists between charged particles
oppositely charged particles have a pull
between them
like charged particles have a push
between them
ENERGY
• MAGNETISM: caused by spinning, moving
charges
• Each atom is a mini-magnet due to the spinning
charges (electrons) inside the atom
• All magnets have a north and south pole
The end of the magnet where the
magnetic field lines point away from
the magnet is the north pole
• Like poles repel, opposite poles attract
• Groups of atoms are called domains
ENERGY
• If the domains of a substance are aligned (north poles point
in the same direction), the
substance is magnetic
• If the domains are random then the substance is not
magnetic
ENERGY
• FRICTION: force that opposes motion between
surfaces that are in contact
• Energy must be exerted in order to overcome
the frictional force
ENERGY
• HEAT: the transference of energy from an object
with higher energy to an object with lower
energy
• As long as there is a difference in temperature
between the objects the transference will
continue
• When the objects have
the same temperature,
the transference stops
and heat is not present
ENERGY
• TYPES OF HEAT TRANSFER:
Conduction
Convection
Radiation
ENERGY
• RADIATION: Some atomic nuclei emit invisible
energy known as nuclear radiation. This
process is called radioactivity.
• Nuclear radiation is energy that is created
whenever certain atomic nuclei emit high
energy particles and rays.
• During radioactivity, also known as radioactive
decay, an unstable nucleus gives off energy
and particles.
ENERGY
• TYPES OF RADIOACTIVE DECAY:
ENERGY
• Radioactive Half-Life: time it takes for ½ of
the nuclei in a sample of mother element to
decay into the daughter element
ENERGY
• TYPES OF NUCLEAR ENERGY: energy that
results from nuclear changes
Fission: large nucleus splits into smaller nuclei
and an energy release, explained by
Fusion: smaller nuclei combine into a larger
nucleus and an energy release, explained by
FORCES
• FORCE: a push or a pull exerted on an object
• Units on Forces: Newtons
• Types of Forces:
Gravity – force of attraction exerted by
objects with mass
Weight – force with which gravity pulls on an
objects mass
Friction – force that opposes the motion of
objects in contact
• Unbalanced forces can change an object’s motion,
balanced forces allow objects to maintain their motion or
non-motion
FORCES
• NET FORCE: the combination of all forces acting on an
object
• Net forces can be
represented with
force diagrams
• Net force greater than
zero results in a motion
change, change is in the
direction of the net force
FORCES
• PRINCIPLES INVOLVING FORCES IN FLUIDS: a fluid
is anything that can flow
Bernoulli
Archimedes
Pascal
• Forces in fluids are related to pressure and
density
• Pressure is defined as the amount of force
exerted on a given area.
FORCES
• BERNOULLI’S PRINCIPLE: as the speed of a
moving fluid increases, the pressure the moving
fluid exerts decreases (the greater the distance
the fluid has to go the faster it moves)
• This principle
explains the
process involved
in flight
FORCES
• Archimedes Principle: the buoyant force on an
object in a fluid is an upward force equal to
the weight of the fluid that the object
displaces when it is placed in the fluid.
FORCES
Floating, Sinking, and Density
•An object that is more dense than the fluid will
sink in the fluid.
•An object that is less dense
than the fluid will float on the fluid.
• An object that has the
same density as the fluid will be
suspended in the fluid.
FORCES
• CHANGING OVERALL DENSITY: By altering an
object’s volume, you can decrease its average
density and increase the amount of water it
displaces. Consequently, you increase the
likelihood it will float. Example: ship
.
FORCES
• PASCAL’S PRINCIPLE: a change in pressure at
any point in an enclosed fluid will be
transmitted equally to all parts of that fluid
FORCES
• Newton’s 1st Law: balanced forces
An object at rest remains at rest and an object in motion
remains in motion at constant speed and in a straight line
unless acted on by an unbalanced force, also known as the
Law of Inertia
• Inertia: tendency of an object to resist any change in its
motion or non-motion
• Newton’s 2nd Law (F=ma): unbalanced forces
the acceleration of an object depends on the mass of the
object and the amount of force applied
• Newton’s 3rd Law: forces in pairs
For every action there is an equal and opposite reaction.
FORCES
FORCES
• All objects accelerate toward Earth at a rate of 9.8
m/s2 in free fall due to gravity. For every second
that an object falls, its downward velocity
increases by 9.8 m/s.
• As the speed of a falling object increases, air
resistance also increases and acts as an upward
force.
• When air resistance force equals gravitational
force, the object stops accelerating because the
net force is zero. This is terminal velocity. From
this point the object falls to Earth at the same
velocity.
FORCES
• SPEED: determined by the distance an object travels
and the time it takes
• VELOCITY: speed in a particular direction
• ACCELERATION: rate at which velocity changes, will be
positive if speeding up, negative if slowing down
• MOMENTUM: mass in motion, determined by the
amount of mass and the speed of the object
• IMPULSE: force applied over time
• Impulse–momentum theorem: states that the change
in momentum of an object equals the impulse applied
to it.
FORCES
• DISTANCE VS DISPLACEMENT
distance: total amount of ground covered
displacement: overall difference between
starting point and ending point
FORCES
• . Projectile Motion and Gravity
Projectile motion is the curved path an object
follows when it is thrown outward near Earth’s
surface.
Projectile motion has 2
independent components;
horizontal motion (due to
the launcher)and
vertical motion (due to gravity)
• When trying to hit a target, always aim high to
allow for the parabolic path the projectile will take
WAVES
• WAVE: any disturbance that transmits energy
through a medium or empty space
• DISTURBANCE: rhythmic motion
• Most waves transfer energy by the vibration of
particles. This vibration is transferred from
particle to particle.
• Waves can be classified according to how the
particles vibrate compared with the direction
in which the energy wave is moving.
WAVES
• TYPES OF WAVES:
mechanical transverse – requires a medium, particles
vibrate perpendicular to the direction of the energy
movement
mechanical longitudinal – requires a medium, particles
vibrate parallel to the direction of energy movement
electromagnetic transverse – does not require a
medium, particles vibrate perpendicular to the direction of
the energy movement
surface - particles in the medium of a surface wave
move in circles, particles move forward at the crest and
backward at the trough.
WAVES
•
TRANSVERSE WAVE:
•
LONGITUDINAL WAVE:
•
SURFACE WAVE:
WAVES
•
WAVE PROPERTIES:
•
•
•
Amplitude – energy level of the wave
Wavelength – frequency of the wave
high energy = short wavelength
high amplitude
high frequency
•
low energy = long wavelength
low amplitude
low frequency
WAVES
• SOUND:
amplitude (energy) tells you how loud it is
frequency (determined by
wavelength) tells you the pitch
•
LIGHT:
amplitude (energy) tells you how bright it is
WAVES
• ELECTROMAGNETIC SPECTRUM: an
arrangement of light energy by wavelength,
frequency, and energy levels
WAVES
• WAVE INTERACTIONS:
reflection – waves bounce off a barrier
refraction – waves bend when moving between 2
mediums
diffraction – waves bend to go through an opening
or around a barrier
absorption – waves are absorbed by the medium,
energizes the medium
interference – overlapping of waves that occupy
the same space at the same time, can be constructive or
destructive
WAVES
• LENSES: refract
concave diverging
convex converging
WAVES
• MIRRORS: reflect
concave- image either
right side up or
upside down,
determined by distance
from mirror
convex- right side up
plane- right side up