Transcript Document

Matter
• Everything is matter
• Matter is anything that has mass and volume (occupies
space)…matter can exist as a solid, liquid, gas, or plasma
• Mass is the amount of matter that an object has
• Volume is the amount of space an object takes up
• MASS AND WEIGHT ARE NOT THE SAME!!!...why?
• All matter, both living and non living, is composed of
ATOMS
Atoms
• All matter is composed of atoms
• Atoms are the smallest particle
of matter
• They are the simplest part of an
element that keeps all of the
properties of the element it
makes up
• The different types of atoms
determines how matter will be
made up
• The ancient Greeks said that
matter must be made up of tiny
particles they called “atomos”
meaning “indivisible”
• Atoms are extremely small…a
teaspoon of water contains
500,000,000,000,000,000,000,0
00 atoms
• Atoms contain protons (+) charge,
neutrons with no charge, and
electrons (-) charge
Elements
• Elements are pure
substances that are
made of only one kind of
atom
• They cannot be broken
down chemically into
simpler kinds of matter
• They are made of only
one type of atom!
• There are over 100
known elements
• Fewer than 30 are
important to life
• Over 90 percent of the
mass of living things
contains combinations of
just four elements. They
are Nitrogen, Oxygen,
Carbon, and Hydrogen
(CHON)
Molecules
• A group of 2 or more atoms that are joined by a bond
are called molecules
• The smallest part of substances such as water, H2O,
would be referred to as a molecule
• Molecules may contain as few as two atoms, or as
many as a million
• Most elements can interact
with others to form compounds
Compounds
• all compounds are molecules
but not all molecules are
compounds
• A compound is a molecule
that contains two different
kinds of elements
• Remember that compounds are
2 different atoms joined by a
bond
• The properties of a compound
are nothing like the elements
that make it up
Chemical
• Chemical formulas show the
of each element in
Formulas proportion
each compound (H2O) for
example 2 Hydrogen : 1
oxygen atom
• Properties of a compound
NH3
Subscripts
differ from the properties
of the elements that
compose it…depends on the
type of bond
• The same elements can make
different compounds…they
have different chemical
formulas (CO, CO2); (H2O,
H2O2)…look at the elements
involved!
• In a chemical formula
coefficients show how many
molecules are present
• Subscripts show how many of
each element are
present…don’t write 1
States of Matter
• Matter is anything that has mass
and volume
• States of Matter are the
different forms in which matter
can exist
• Matter exists in 4 states…solids,
liquids, gases, and
plasma…which is found inside
stars
• A solid holds a particular shape
and has a definite volume…an
orderliness exists to the particles
of a solid
• A liquid does not hold its own
shape, but it does occupy a
definite volume. It flows freely
and takes the shape of its
container
• A gas has no definite shape or
volume. It expands to fill
available volume of its container
http://www.harcour
tschool.com/activit
y/states_of_matter
/
1. In a gas the molecules are far apart and
move at high speeds
2. In a liquid the molecules are more closely
together, but still move rapidly; they slide
over each other allowing them to pour
3. Solid molecules are held tightly together;
they wiggle
4. Plasma is typically a gas that has lost electrons. Plasma is different from
gases because of its unique properties. Plasma consists of a collection of free
moving electrons and ions – (atoms that have lost electrons). With insufficient
sustaining power, plasmas recombine into neutral gas. Plasmas are the most
common state of matter in the universe
Changes in State
• Now that we know that matter has
different states, its time to learn
what the process of changing state
is called.
• Melting is the process by which a
substance changes from its solid
state to its liquid state…the
melting point is the temperature
at which this happens
• Boiling is the process by which a
substance changes from its liquid
state to its gaseous state…the
temperature at which this happens
is its boiling point
• Condensation is the process by
which gases become liquids
• Freezing is the process by which a
liquid becomes a solid…the
freezing point is the temperature
it does this
• Sublimation is the process of going
from the solid state to the gas
state…desublimation or deposition
is the opposite of this
Pure Substances vs. Mixtures
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Most substances we encounter are not chemically pure…air, cement, gasoline
We can separate these substances into different pure substances
Pure substances = matter with fixed composition and distinct properties…water,
table salt, the elements…Pure substances can’t be broken down physically
Substances are classified as either elements or compounds
Elements cannot be decomposed into simpler substances…composed of only one
kind of atom…they are pure substances
Compounds are composed of two or more elements, containing two or more
different kinds of atoms
Pure Substances vs. Mixtures
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Mixtures are combinations of two or more substances…each substance retains
its own chemical identity and its own properties
Mixtures are different
Coffee can be a little sweet or a lot…the substances making up a mixture (sugar,
coffee, and water) are called components of the mixture
Heterogeneous mixtures do not have the same composition throughout…sand,
rocks, a salad. Can see it in appearance, properties, and compositions.
Homogenous mixtures are those who are the same throughout ...air, salt &
water… also called solutions
Solutions
• A solution is a type of mixture, a homogenous mixture
• Sand in water is a mixture that is not a solution; Sugar in water can’t be
identified as two separate substances, it is a solution
• A solute is a substance that is dissolved to make a solution…the sugar
• A solvent is the substance that dissolves the solute…water
• Water is the most common and important solvent
• Solutions don’t have to be made from a solid dissolved in a liquid…oxygen
gas is dissolved in seawater; vinegar is acetic acid (liquid) in water
• With two liquids, the substance that has the greater amount is the
solvent
• Two solids can also form solutions…tin + copper = bronze; Copper + Zinc
= brass…these solid mixtures of metals are called alloys
• The air we breathe is a solution of gases with nitrogen as the solvent
• A mixture where the particles of a solute do not dissolve but make the
solvent cloudy is called a suspension
Properties of Matter
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Properties are characteristics that
allow us to recognize a substance and
to tell it apart from others
Physical properties are the
characteristics of a substance that
can be seen without altering the
identity of the substance
Density, color, boiling point, hardness,
and melting point are examples of
physical properties
Chemical properties are the
characteristics of a substance that
cannot be observed without altering
the substance…they describe the way
a substance may change or react to
form other substances…they can be
seen during a chemical reaction
Flammability is a chemical
property…the ability of a substance to
burn in the presence of oxygen;
rusting; radioactivity; reactivity with
an acid
Properties can be extensive (depends
on how much you have) or intensive
(doesn’t depend on how much)
Changes in Matter
• Physical changes involve the changing of a substance without altering
its identity…appearance changes without changing composition
• Crushing and tearing are physical changes as well as changes in state
• Chemical changes, or chemical reactions, do alter the identity of a
substance
• A piece of wood undergoes chemical changes as it burns
• Food changes when it cooks
• Metal changes when it rusts
• Signs of a chemical change include: Production of odor, change in
temperature, change in color, production of bubbles (gas), formation of
a solid (precipitate)
Properties of Matter
• We can identify unknown substances and separate the components of
a mixture by taking advantage of their different properties
• To identify unknowns, use properties like melting pt., density, heat
properties, solubility, electric properties, and magnetic properties.
• You can separate based on appearance, magnetism, filtration,
distillation, density, melting pt., or solubility to name a few
• Properties of a compound are nothing like the properties of the atoms
that make them up!
Conservation of
Matter
• Matter, like energy, is
neither created nor
destroyed in any process
• This is the Law of
Conservation of Matter
• In every reaction there is
an equal quantity of
matter before and after
• Explained by Antoine
Lavoisier, a French
scientist also called “the
father of modern
chemistry”
• Matter can also be
converted to energy E=mc2