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52 terms

Science Midterm

STUDY
PLAY
composition of matter never changes, different shape, form or appearance
explain what it means when matter undergoes a physical change
solid>liquid
ripped paper
broken pencil
give three examples of a physical change
composition of matter always change, new substances are formed by the reorganization of atoms (the making and breaking of bonds)
explain what it means when matter undergoes a chemical change
-change in color
-bubbles or gas given off
-change in energy
give 3 possible clues that a chemical change has taken place
matter can be neither created nor destroyed during a chemical reaction
mass of reactants=mass of products
explain the law of conservation of matter
so no matter is lost or gained
why would you use a closed system when trying to prove the law of conservation of matter?
pure substances
mixtures
what are the 2 main classification groups of matter?
homo- mixed well
hetero- not mixed well
same- made up of elements and compounds+mixtures
explain how a homogeneous mixture differs from a heterogeneous mixture and in what ways are they similar?
atom- smallest part of an element
molecules- smallest part of a compound
what is the difference between an atom and a molecule?
pure substance that cannot be seperated into similar substances
what is an element?
pure sustance that is made up of 2 or more chemically combined elements
what is a compound?
element- oxygen, hydrogen, gold
compound- water, salt, alcohol
give three examples of an element, three examples of a compound
homo- soda, air, coffee
hetero- ocean water, mikes+ikes, smoothie
give 3 examples of a homogeneous mixture and 3 examples of a heterogeneous mixture.
a homogeneous mixture
what is a solution?
characteristic properties
when substances are in a mixture what does each substance keep?
solid
liquid
gas
name the 3 main states of matter
thermal energy
what is the "critical" factor that changes matter from one state to another?
has mass and volume
made up of pure substances and mixtures
what is the definition of matter? What does all matter have in common?
tightly packed
vibrate slightly in place
explain how the atoms and molecules arrange themselves and move in a solid.
close but not too close
free to move in container
explain how the atoms and molecules arrange themselves and move in a liquid
far apart
move quickly and freely
explain how the atoms and molecules arrange themselves and move in a gas
crystalline- repeating pattern, distinct melting point
amorphous- random pattern, no distinct melting point
what is the difference between a crystalline and an amorphous solid?
measurment of the resistance of a liquid to flow
high- syrup, glue
low- water, vinegar
what is viscosity? name 2 liquids with high viscosity and 2 liquids with a low viscosity.
a measurement of the inward pull by particles on the interior of a liquid
high- water
what is surface tension? what liquid demonstrates high surface tension?
melting
melting point
what term describes the process when matter changes state from a solid to a liquid? What is this temperature called?
vaporization
boiling point
what term describes the process when matter changes state from a liquid to a gas? What is this temperature called?
deposition
what term describes the process when matter changes state from a gas to a solid?
condensation
what term describes the process when matter changes state from a gas to liquid?
sublimation
what term describes the process when matter changes state from a solid to a gas?
freezing
freezing point
what term describes the process when matter changes state from a liquid to a solid? What is this temperature called?
anything that flows
what is a fluid?
at constant temperature, the volume of a gas is inversely proportional to it's pressure
(volume decreases as pressure increases)
explain Boyle's Law
at constant pressure, the volume of a gas is directly related to it's temperature
(Temperature increases as volume decreases)
explain Charles's Law
when gas particles collide with the container wall they exert an outward push
what is pressure?
properties that don't change regardless of size or shape
what is a characteristic property?
boiling point
melting point
density
give three examples of a characteristic property.
vaporization- liquid>gas, whole liquid ex. boiling water
evaporation- liquid>gas, surface of a liquid, ex. puddle dries up
what is the difference between vaporization and evaporation? Give one example for each.
pressure
temperature
volume
what are the 3 characteristic properties that are used to describe gas behavior?
protons, nuetrons, and electrons
protons and nuetrons are found in the nucleus of an atom while electrons are found in the outer energy shells which surround the nucleus of an atom
what subatomic particles make up an atom and where are they located?
postive charge
what charge does a proton have?
no charge. it is nuetral
what charge does a nuetron have?
negative charge
what charge does an electron have?
those electrons involved in forming chemical bonds
what is a valence electron?
heat is transfered from one particle of matter to another without the movement of the matter. only solids move heat by conduction
ex. touching a stove and being burned
what is conduction? Give an example
heat is transfered by the movements of currents within a fluid
ex. cooling down
what is convection? give an example
the transfer of energy by electromagnetic waves. unlike conduction and convection, radiation does not require matter to transfer thermal energy
ex. heat from a lightbulb
what is radiation? give an example
thermal energy
thermal energy on the move
what is heat? is it matter or energy?
heat flows from hot/warm>cool
heat continues to flow until equilibrium is reached
in what direction does heat flow? when does heat stop flowing?
gases have no definite shape or volume and their particles are very spread out
why are gases so easy to "manipulate" unlike solids and liquids?
conductor
ex. nickel, copper, aluminum, stainless steel
what is matter called that allows for heat to move through easily?
insulator
ex. rubber, plastic
what is matter called that does not allow for heat to move through easily?
boiling point, melting point, freezing point, density, magnetism
if you had 2 samples of the same substance but of different masses, what are some properties that would remain the same?