Download Properties of Mixtures

LET’S STUDY FOR THE CRCT!!!

S8P1A – DISTINGUISH BETWEEN ATOMS AND MOLECULES
• Atom = The smallest particle of an element; composed of a nucleus (which
contains the protons and neutrons) and electrons circling the nucleus on
energy fields
• The subscript in the chemical formula states the number of atoms of a
particular element in that formula
• Example = H2O; the number 2 lets us know that there are 2 atoms of
hydrogen in water
• Molecule = A combination of two or more atoms that are bonded together
(examples include N2, H2, and H2O)
• The coefficient in front of a chemical formula states the number of
molecules you have
• Example = 4H2O; the number 4 lets us know that there are 4 molecules of
water
S8P1B – DESCRIBE THE DIFFERENCE BETWEEN PURE
SUBSTANCES (ELEMENTS AND COMPOUNDS) AND MIXTURES
• Elements and compounds are pure substances
• Pure substances = A substance that is made of only one type of atom or
molecule
• Elements = A substance that cannot be broken down into other substances
by chemical or physical means; examples include gold, carbon, copper,
silver, oxygen, boron, and nitrogen
• Compounds = A substance made of two or more elements chemically
combined; examples include table salt, table sugar, and water
• Mixtures = Two or more substances that are mixed together but not
chemically combined; examples include ice cream, kool aid, pizza, and milk
PROPERTIES OF MIXTURES AND COMPOUNDS
• Properties of Mixtures
– The composition of a mixture is variable (it changes).
– Each of its components retains its characteristic properties.
– Its components are easily separated.
• Properties of Compounds
– The relative proportions of the elements in a compound are fixed (it does not
change).
– The components of a compound do not retain their individual properties.
Both sodium and chlorine are poisonous; their compound, table salt - NaCl - is
absolutely essential to life.
– It takes large inputs of energy to separate the components of a compound.
S8P1C – DESCRIBE THE MOVEMENT OF PARTICLES IN
SOLIDS, LIQUIDS, GASES, AND PLASMAS STATES
• Solids = A state of matter with a definite shape and volume
• The particles in solids are packed tightly together and stay in fixed positions
(the particles are still moving, but it is extremely slow)
• Liquids = A state of matter that has a definite volume but no definite shape
• The particles in liquids move around one another freely and take the shape
of whatever container it is poured into (particles move faster than a solid,
but slower than a gas)
• Gases = A state of matter with no definite shape or volume
• The particles in gases spread apart, filling all the space available to them
(particles move fast)
• Plasmas = A state of matter in which atoms are stripped of their electrons
and the nuclei are packed closely together
S8P1D – DISTINGUISH BETWEEN PHYSICAL AND CHEMICAL
PROPERTIES OF MATTER AS PHYSICAL OR CHEMICAL
• Physical properties = Characteristics of matter – such as color, shape,
taste, and density – that can be detected by the senses without
changing the identity of the matter.
• Examples = Melting point, boiling point, density, color, shape, size
• To determine the density of an object, you need to divide the mass by
the volume of that object
• Chemical properties = Characteristics of something that permits it to
change into something else
• Examples = reactivity ( how something reacts with something else),
combustibility (how something reacts with oxygen), flammability (how
something burns), and whether it is an acid or a base (its pH)
S8P1E – DISTINGUISH BETWEEN CHANGES IN MATTER AS
PHYSICAL OR CHEMICAL
• Chemical changes = A change in matter that produces new substances;
examples include burning a match, the rusting of a bike, tarnish on silver, and
place an alka seltzer tablet into water
• Signs that a chemical change has taken place include color change (that can
not be reversed – like a leaf changing colors), a precipitate (combining two
liquids and making a solid), gas production (like the smoke from burning a
match), changes in properties (like flour, eggs, butter, etc. changing into cake),
and changes in temperature (like the match being hot after it has been struck)
• Physical changes = A change that alters the form or appearance of a
substance but does not make the material into another substance; examples
include tearing paper into pieces, cutting wood, and melting ice into water
S8P1F – RECOGNIZE THAT THERE ARE MORE THAN 100
ELEMENTS AND SOME HAVE SIMILAR PROPERTIES
• Periodic Table = An arrangement of the elements in order of atomic
number, in which elements with similar properties are grouped in
columns
• There are approximately 112 elements on the periodic table
• Groups (Families) = Elements in the same vertical column of the
periodic table; elements in the same group (family) have similar
properties
• Periods = A horizontal (left to right) row on the periodic table;
elements in the same period have the same number of valence
electrons (same number of electrons on the outermost energy level)
S8P1G – IDENTIFY AND DEMONSTRATE THE LAW OF
CONSERVATION OF MATTER
• Law of Conservation of Matter = States that matter is not created or
destroyed but only changes its form
• Sample of the Law of Conservation of Matter:
K + AgCl → KCl + Ag
• This is NOT a sample of the Law of Conservation of Matter:
Na + CuS → Na2S + 2 Cu - WHY? It does not have the same
number of atoms of each
element on both sides
• The total quantity of matter and energy available in the
universe is a fixed amount and never any more or less.
S8P2A – EXPLAIN ENERGY TRANSFORMATION IN TERMS OF
THE LAW OF CONSERVATION OF ENERGY
• Law of Conservation of Energy = The rule that energy cannot be
created or destroyed
• There is the same amount of energy today as there was at the
beginning of time = the total amount of energy is constant
• Energy Transformations (Energy Conversions) = The process of
changing one form of energy into another
• Examples of Energy Transformations:
– Windmill = mechanical to electrical
– Battery = chemical to electrical
– Eating = chemical to mechanical or chemical or potential
S8P2B – EXPLAIN THE RELATIONSHIP BETWEEN POTENTIAL
AND KINETIC ENERGY
• Potential Energy = Energy that is stored and held in readiness
• The higher an object is, the more potential energy it contains
• The heavier an object is, the more potential energy it contains
• Example = On the top of the highest hill of the roller coaster, the
roller coaster has the most potential energy
• Kinetic Energy = Energy that an object has because of its motion
• Kinetic energy is also known as the energy of motion
• Something has to be moving in order for it to have kinetic energy
• Example = A ball falling, a car rolling, and an arm moving
S8P2C – COMPARE AND CONTRAST THE DIFFERENT FORMS
OF ENERGY AND THEIR CHARACTERISTICS
• Heat (Thermal) = The total energy of the moving particles in an object
• Light (Radiant or Electromagnetic) = Energy that travels in the form of
waves that have both electrical and magnetic properties
• Electrical = Energy from moving electric charges
• Chemical = Energy stored in chemical bonds
• Mechanical = Energy associated with the motion or position of an
object
• Sound = Energy caused by an object’s vibrations
S8P2D – DESCRIBE HOW HEAT CAN BE TRANSFERRED BY
RADIATION, CONDUCTION, AND CONVECTION
• Radiation = The transfer of energy by electromagnetic waves
• Example = the sun’s rays, the heat from a stove if you were to put your
hand over it
• Conduction = The transfer of thermal energy between two particles within
a substance; the transfer of electrons from a charged object to another
charged object
• Example = your feet burning from hot concrete, a metal spoon’s handle
warming from being in hot water, warm hands touching your face
• Convection = The transfer of thermal energy by the movement of currents
within a liquid or gas
• Example = upstairs being warmer than downstairs, boiling water, wind
S8P3A – DETERMINE THE RELATIONSHIP BETWEEN
VELOCITY AND ACCELERATION
• Velocity = Speed in a given direction
• The unit for velocity is m/s = distance divided by time
• Acceleration = The rate at which velocity changes
• The unit for acceleration is m/s2 = velocity divided by time
S8P3B -DEMONSTRATE THE EFFECT OF BALANCED AND UNBALANCED FORCES ON AN
OBJECT IN TERMS OF GRAVITY, INERTIA, AND FRICTION
• Inertia – Tendency to resist any change in motion
• Gravity – A force of attraction between all objects. The force of
attraction depends on the mass of the objects and the distance
between the objects
• Friction – The force the opposes the motion of an object.
• Unbalanced force has a net force greater than zero
• Balanced force has a net force that equals zero
• Net force – A total combination of all the forces acting upon an object
S8P3C - DEMONSTRATE THE EFFECTS OF SIMPLE MACHINES (LEVER, INCLINED
PLANE, PULLEY, WEDGE, SCREW, AND WHEEL AND AXLE) ON WORK.
• A machine is a device that makes work easier by changing the
direction or the size of the force.
• Effort – The force applied to move a load using a simple machine
• Work = Force * Distance
http://www.generalpatton.org/education/sm_unit/simple_machines_ind
ex.htm
4A - IDENTIFY THE CHARACTERISTICS OF
ELECTROMAGNETIC AND MECHANICAL WAVES
• Mechanical waves need matter to transfer energy, while
electromagnetic waves do not- they can travel through space, or a
vacuum.
• Electromagnetic waves include the electromagnetic spectrum... (This
includes visible light, radio waves, gamma rays, x-rays, ultraviolet
rays, infra-red waves, and microwaves.)
• They both are able to travel through a medium of gas, liquid, or solid.
4B - DESCRIBE HOW THE BEHAVIOR OF LIGHT WAVES IS MANIPULATED
CAUSING REFLECTION, REFRACTION, DIFFRACTION, AND ABSORPTION
• Waves that meet each other or an object in the environment may interact. There are
several types of interactions that waves may have.
• Reflection occurs when a wave bounces back after striking a barrier. Reflected sound
waves are called echoes; reflected light waves allow us to see objects.
• Refraction is the bending of a wave as it passes at an angle from one medium to
another. One common example of refraction of light waves is the broken pencil effect that
can be observed when a pencil is placed in a glass of water. The pencil seems to be
"broken" at the surface of the water as the light waves go from the air to the water.
• Diffraction is the bending of waves around a barrier or through an opening. The amount
of diffraction a wave experiences depends on two factors: the wavelength of the wave
and the size of the barrier or opening the wave encounters. Sound travels around corners
because it has relatively larger wavelengths than light. We can hear sounds around
corners. We can't see around corners because light has a very small wavelength.
4C - EXPLAIN HOW THE HUMAN EYE SEES OBJECTS AND
COLORS IN TERMS OF WAVELENGTHS
4D - DESCRIBE HOW THE BEHAVIOR OF WAVES IS AFFECTED
BY MEDIUM (SUCH AS AIR, WATER, SOLIDS)
• Waves either speed up or slow down in different mediums (air, water,
solids)
• Sound travels fastest in solids and slowest in gases
• Speed of light is only constant in vacuums (and it goes fastest in
vacuums)
• The speed of light is so slight in other mediums that it is unnoticeable
4F - DIAGRAM THE PARTS OF THE WAVE AND EXPLAIN HOW THE PARTS ARE
AFFECTED BY CHANGES IN AMPLITUDE AND PITCH
• The amplitude of a wave is the maximum distance the wave vibrates from its rest position. The rest
position of a wave is where the particles of a medium stay when there are no disturbances. The larger the
amplitude, the greater is the energy of the wave.
• Wavelength is the distance between two adjacent crests or compressions in a wave. Therefore wavelength
is the distance from any point on a wave to the corresponding point on the next wave.
• Frequency is the number of waves produced in a given amount of time. Frequency can be measured by
counting either the number of crests or the number of troughs that pass a point in a certain amount of time.
Frequency is expressed in hertz (Hz). Higher frequency, just like higher amplitude, means more energy.
• Wave speed is the speed at which a wave travels. The speed of a wave depends on the medium in which
the wave is traveling. Sound waves travel fastest in solids, next fastest in liquids, and slowest in gases.
Wave speed can be calculated by multiplying the wavelength (represented with the Greek letter lambda)
times the frequency of the wave.
5B - DEMONSTRATE THE ADVANTAGES AND DISADVANTAGES OF SERIES AND
PARALLEL CIRCUITS AND HOW THEY TRANSFER ENERGY
• An advantage to parallel circuits is that if one component fails the circuit is
not broken, therefore allowing the rest of the components to receive
electricity. A good example of this is a string of Christmas lights which are
wired in parallel so that if one bulb blows the entire circuit is not broken.
• What is arguably the major disadvantage of a parallel circuit is that as you
add more and more things in parallel, the current draw on the source goes
up and up and up. If the source cannot supply the current that is
"demanded" by the devices all strapped across the so-called "rails" of the
circuit, the voltage will (must!) decrease. This could be very bad, as some
devices, notably motors, don't like to run at low voltage and can actually be
damaged if voltage sags too much and they don't have undervoltage
protection
5C - INVESTIGATE AND EXPLAIN THAT ELECTRIC CURRENTS
AND MAGNETS CAN EXERT FORCE ON EACH OTHER
• Electric currents and magnetic fields are by nature and by definition related to
each other. In general, a magnetic field is created by the rotation of charge. If you
imagine an electron following a circular path, a magnetic field would be created in
the direction perpendicular to the plane of the circle.
• On the other hand, electric current is defined as the flow of charge. So, an electron
flowing along a wire results in current flow. This also means that the electron
following a circular path (as above) creates an electric current along that same
path.
• If a circular flow of current results in a magnetic field perpendicular to the circle,
what happens for current flow along a straight wire? Basically, we see a magnetic
field which bends around the wire. Imagine exactly the reverse as before, with the
magnetic field circling around the direction of current flow.