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Miss Wellers Chemclass

Terms

undefined, object
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composition
what matter is made of;
properties
what the matter is like; how matter behaves; earthquakes
matter
anything that has mass and volume
mass
the amount of matter in an object
What does an object’s weight depend on?
how hard gravity pulls on it
this will vary, depending on location
An object’s mass does NOT
no matter where it is.
volume
the amount of space an object occupies
atom
The most basic unit of matter
molecule
a neutral group of atoms held together by chemical bonds
At the smallest level, all matter is composed
of atoms.
All matter can be classified as either
a pure substance or a mixture.
pure substance
a type of matter for which all samples have the same properties; they behave exactly the same way
there are 2 types of pure substances,
elements and compounds.
elements
samples of a substance that contain only one type of atom
An element CAN’T be broken down into simpler substances
by chemical means.
allotropes
different forms of an element in the same physical s
compound
a substance made up of 2 or more different elements that are chemically combined
Properties of Compounds
every sample of a particular compound has the same properties as every other sample
mixture
a combo of 2 or more substances; each retains its individual properties
In a mixture, there are no ______________between the different substances.
Chemical bonds
There are 2 types of mixtures
homogeneous mixtures and heterogeneous mixtures
homogeneous mixture
all regions of a homogeneous mixture are identical in composition and properties
Homogeneous mixtures are evenly-mixed, or uniformly distributed, at the particle level, and are also referred to as
Solutions
alloy
a homogeneous mixture of 2 or more metals
heterogeneous mixture
some regions have different composition and properties than other regions
In heterogeneous mixtures, although the particles may appear to be evenly mixed at the macroscopic level, they are NOT
uniformly-distributed at the microscopic (particle) level.
suspension
appears uniform while stirred; settles when agitation stops
colloid
contains tiny particles that never settle out
Physical Separation
we say that we separate them physically (without chemical reactions),
Magnet separates mixtures
Physically
Filter
Physically
Evaporation
Physically
Chromatography
Physically
Distillation
Physically
Centrifuge separates mixtures
Physically
density of a sample of matter is
he quantity of mass of that substance that occupies one unit of vol.; density is a constant ratio of mass to volume
Formula for density:
(measures mass)
D= M/V
units for density are always
mass / volume units
extensive properties
depend on the size of the sample
Examples: volume, weight, mass, heat content
intensive properties
DO NOT depend on the size of the sample
Examples: density, temperature, hardness, color
physical properties are
observed wo/changing the chem. composition of the matter
Examples: color, texture, mass, state of matter, melting point, elec. conductivity
ductility, malleability, luster
physical properties for metals
ductility, malleability, luster
chemical properties
hese describe how the substance reacts (or fails to react) with other substances to produce new substances
Examples: reactivity with acid, reactivity with oxygen (flammability)
physical change
occurs when a physical property of a substance changes without any change in the substances chemical properties or composition

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