What is Chemistry?
THE STUDY OF MATTER!!!
Composition
Structure
Properties
What is matter?
DEFINITION: It is anything that
has a mass and takes up
space!
Why does MATTER matter?
How do we categorize
matter?
3 MAIN STATES OF MATTER
SOLID
LIQUID
GAS
Which
picture
represents:
A solid, A
liquid, A
gas?
The kinetic theory
Kinetic Theory: all matter consists of
tiny particles that are in constant motion
The particles of Solids, Liquids, and Gases
are ALWAYS moving!
Kinetic energy the energy an object has
because of its motion
Temperature the measure of the average
PhET: The motion of the
particles
https://
phet.colorado.edu/en/simulation/states-of-matter-b asics
The particles of which state of matter
display the MOST amount of
motion/movement?
GAS
Which display the LEAST amount of
motion/movement?
PhET: The motion of the
particles
https://
phet.colorado.edu/en/simulation/states-of-ma tter-basics
Which state(s) of matter consist of
particles that move from place to
place?
PhET: The motion of the
particles
https://
phet.colorado.edu/en/simulation/states-of-ma tter-basics
What happens to the motion of
the particles as you go from a
gas to a liquid to a solid?
PhET: The motion of the
particles
https://
phet.colorado.edu/en/simulation/states-of-ma tter-basics
What happens to temperature
as you go from a solid, to a
liquid, to a gas?
PhET: The motion of the
particles
https://
phet.colorado.edu/en/simulation/states-of-matter-ba sics
Which state of matter would have
the HIGHEST kinetic energy (energy
of motion)?
GAS
Which would have the LOWEST kinetic
energy?
PhET: The arrangement
of the particles
https://
phet.colorado.edu/en/simulation/states-of-ma tter-basics
Which state of matter has particles
which are CLOSEST together?
Solid
Which state of matter has particles
which are the FURTHEST apart?
Which picture best describes oxygen
gas?
SOLIDS
Particle
Arrangement
Tightly compacted
particles (close together)
Definite Shape
Definite Volume
Particle
Motion
Particles vibrate in
a fixed position.
They CANNOT
LIQUIDS
Particle
Arrangement
Indefinite Shape
Definite Volume
Particle
Motion
The particles slide
past one another.
It is a fluid- it
‘flows’
Move from place
GASES
Particle
Arrangement
Indefinite Shape
Indefinite Volume
The particles are
spread out- gases are compressible
Particle
Motion
The particles move
very fast and from place to place
It is a fluid- it
Summary: states of
matter
MOTION: SOLID LIQUID GAS
SPACE BETWEEN PARTICLES: SOLID
LIQUID GAS
Kinetic Energy (energy of motion): SOLID
LIQUID GAS
<
<
<
<
How can we go from one
state of matter to another?
Think about a glass of ice
water on a hot day…
What happens to the ice?
What forms on the
outside of the glass?
Why?
Phase Changes- changes
in state of matter
♦
Solid to liquid – melting (fusion)
♦Liquid to solid – freezing
♦
Liquid to gas –
evaporation/vaporization
http://itl.chem.ufl.edu/4411/2041/lec_f.html
A phase diagram is a graph which
represents the conditions (temperature and pressure) at which a substance
exists as a solid, liquid, and/or gas.
PHASE
DIAGRAM!
Warm up: Thurs 9/10
The particles of which
state of matter contain
the most kinetic
review
What does the Kinetic Theory
state?
The particles of which state of
matter experience the least
review
Why does a solid have a definite
shape and
volume?
The arrangement of its particles!
Explain why a gas can be
9/11 warm up:
At what temperature and pressure can all 3 states of matter exist at once?
72.9 5.1 1.0 P re ss ur e (a tm ) Temperature (°C)
Review: What state of matter
exists when P= 1 atm and T=
20°C
72.9 5.1 1.0 P re ss ur e (a tm ) Temperature (°C)Review: What state of matter
exists when P= 3 atm and T=
-78.5°C
20.0 5.0 1.0 P re ss ur e (a tm ) Temperature (°C)-78.5°C -56.7°C 31°C
What phase change would occur if the substance was then
THINK QUESTION
Why does it take longer to boil an
Changes in Matter and Energy
Matter cannot be created or destroyed.
However it can be changed!
Energy – the capacity to do work or
produce heat
Energy is always involved in physical
and chemical changes.
Energy can take several forms: Heat,
light, (sound, chemical, electrical)
Measured in calories, Calories (kcal),
Law of Conservation of Energy:
energy can be absorbed or
released, but it
cannot
be created
or destroyed through ordinary
chemical reactions.
Energy
can
be transferred.
It flows from high concentration to
low concentration.
Since energy can’t be destroyed it
Exothermic
ENERGY IS RELEASED
A Process or Reaction that
releases energy in the form of
heat.
Endothermic
ENERGY IS ABSORBED
A Process or Reaction that absorbs
Warm up 9/14
What is the difference
Warm up 9/14
Endothermic: heat is
absorbed!
Phase changes?
Exothermic: heat is released!
Which phase changes are
Which phase changes are
endothermic or exothermic?
Warm up: Tuesday 9.15
At what segments is Kinetic Energy
CHEMICAL and PHYSICAL
Properties
What is a property?
Characteristics that allow us to
distinguish or identify matter.
Can be described as:
PHYSICAL or CHEMICAL.
QUALITATIVELY or QUANTITATIVELY.
Properties: Qualitative vs
Quantitative
Qualitative
Data or information
which is NOT numerical
Examples: color,
phase (state of matter), shape, etc.
Quantitative
Data or information
which IS numerical
Example: mass,
Intensive vs Extensive
Properties
INTENSIVE
NOT dependent upon
the AMOUNT of Matter present
Examples: density,
ductility, boiling point, color, etc.
EXTENSIE
DEPENDENT on the
AMOUNT of Matter present
Example: size, mass,
PHYSICAL PROPERTIES
We usually use physical properties
to describe different things:
How would you describe these two
substances?
Silve
r
liqu
id
M
et
al
lic
yell
ow
Physical Properties
Definition: A property that can be
observed or measured without altering
the identity of the substance.
Basically, it describes the substance
itself
Examples: Malleability, Solubility,
Chemical Properties
Definition: a property that
describes the substance’s ability
to participate in chemical
reactions (undergo a change).
Examples: reacts with…,
Chemical and Physical
Changes
Physical change
Definition: A change that does
NOT alter the substance’s
chemical identity.
Usually, these are easily
Examples of PHYSICAL
CHANGES.
♦
Dissolving a substance
♦
Cutting, Grinding, Breaking,
Crushing, etc.
♦
Changes in state (phase changes)
♦
Solid to liquid – melting (fusion)
♦
Liquid to solid – freezing
♦
Liquid to gas – evaporation (vs.
boiling)
♦
Gas to liquid – condensation
♦
Solid to gas – sublimation
Chemical and Physical
Changes
Chemical change
Definition: A change in which a
new substance, with new
chemical properties, is formed.
Chemical Changes
Remember… A chemical change produces
matter (products) with a different
composition than the original matter (reactants)
Basically, it’s a Chemical Reaction!!
In a chemical reaction…
Reactants: substance present at the start
of a reaction
Products: What is produced at the end of
a reaction
Examples of Chemical
Changes
Burning
Rusting
Decomposition
Fermentation
Corrosion
Digestion
Examples of chemical
reactions
What do you think would happen if you comb ine water and sodium?
http://www.youtube.com/watch?v=ODf_sPexS2Q https://www.youtube.com/watch?v=RAFcZo8dTcU
What observations did you make
(what did you notice)???
Were these observations
QUANTITATIVE or QUALITATIVE?
Recognizing chemical changes
4 observations that indicate a
chemical reaction (CLUES)
1.
Gas formation
bubbles or odor
2.
Formation of precipitate (ppt)- a solid
that forms from a liquid mixture
3.
Color Change
4.Energy Change
Recognizing chemical changes
Words to look for:
Rust
Burn
Rot
Decompose
Ferment
SUMMARY:
Chemical vs Physical
Changes
What is the main difference between
a chemical change and a physical
change?
PHYSICAL CHANGE: the composition or
identity
of a substance
does NOT
change
CHEMICAL CHANGE: the composition or
identity
of a substance
DOES
Warm up THURS 9/17
Review of Physical and
Chemical Changes
Most important things to remember!!!!
A physical change does not chemically
alter the substance (or change what the substance is)
A chemical change does alter the identity
of a substance through chemical means. (you start with one thing, you get
Physical changes
Common Physical Changes Phase changes
doesn’t change what the substance
is, just alters its form
Dissolving something (salt in water) The two substances can be
separated
the substances DO NOT undergo a
chemical reaction
Chemical Change
Any type of reaction is a chemical
change…
Plants growing is a chemical change
because it is caused by photosynthesis and other chemical reactions
Another way to classify
matter…
We know we can classify
matter by its state: solid,
liquid, or gas.
But we can also categorize
ATOMS
Definition: The smallest unit of an
element that maintains the properties
of the element.
Atoms are the building blocks of
matter
All matter is made up of atoms!
Atoms contain:
Protons (+)- nucleus
Neutrons (neutral)- nucleus
SUBSTANCES
A substance is something that has
a uniform composition (one that
doesn’t change)
Substances are either ELEMENTS
Substances -
ELEMENTS
ELEMENT: a substance that
cannot
be
separated or broken down into
simpler
substances by chemical means.
Periodic Table!
Can exist as a SINGLE ATOM or as a
MOLECULE
Molecule: the smallest unit of a
substance that keeps all of the physical and chemical properties of that
Element examples…
Single Atoms…
Iron (Fe)
Helium (He)
Molecules (1 or more
atoms bonded together)...
Oxygen (O
2)
More examples of
ELEMENTS
ANYTHING THAT IS LISTED ON THE
PERIODIC TABLE!!!
COPPER - Cu
SODIUM - Na CHLORINE- Cl2
Substances -
COMPOUNDS
COMPOUND:
a substance made up
of atoms of two or more DIFFERENT
elements joined by chemical bonds
Compounds can be broken down into
simpler substances by CHEMICAL means.
A compound’s properties are different
Examples of Compounds
Remember a compound contains at
least 2 DIFFERENT ELEMENTS
SALT -
N
a
C
l
Sucrose–
C
12H
22O
11Copper (II) Chloride
The difference between compounds
and molecules.
All compounds
are molecules
But not all
molecules are compounds
Molecules:
contains 2 or more atoms bonded together
H
2O?
compounds:
contains 2 or more DIFFERENT atoms
bonded together
H
2O
H
2O
P
4N
2NaCl?
NaCl
NaCl
Distinguishing between
elements and compounds
Main difference
compounds
Distinguishing between elements
and compounds (based on the
formula)
There is a quick and easy way to tell
the difference between an element
and a compound:
Look at the periodic table!!! Elements
ONLY contain ONE capitol letter in their
symbols (or formula)
Compounds will always have at least 2
Examples of ELEMENTS
ANYTHING THAT IS LISTED ON THE
PERIODIC TABLE!!!
COPPER - Cu
SODIUM - Na CHLORINE- Cl2
Examples of Compounds
Remember a compound contains at
least 2 DIFFERENT ELEMENTS
SALT -
N
a
C
l
Sucrose–
C
12H
22O
11Copper (II) Chloride
Distinguishing between elements
and compounds based on the
particle diagrams
Atoms of ONE
element
elements bonded together
Atoms of 2 different
ELEMENTS
COMPOUND (NaCl)
(Na)
Warm up: 9/18
List one difference
What can be broken down into
a simpler substance?
What is the difference
between a molecule and a
compound?
Molecule, Compound or Both?
Br
2
CO
2
HCl
Element or compound?
N
2MIXTURES
Mixture: A combination of two or more
substances that are NOT chemically combined.
It is a PHYSICAL BLEND.
Mixtures can be made of different
elements and/or compounds
Mixtures can be separated by PHYSICAL
MEANS.
Ex) Salt Water (water can be
evaporated away and you are left with salt)
MIXTURES: homogeneous
and heterogeneous
HOMOGENEOUS – A mixture with a uniform
composition throughout
Homo means the same
Also called a solution
Examples salt water, stainless steal air
HETEROGENEOUS- a mixture that does NOT
have a uniform composition throughout.
It is composed of dissimilar components.
Examples chicken noodle soup,
Heterogeneous vs.
homogeneous
Matter
Matter
Substance
Uniform
composition
Substance
Uniform
composition
Mixture of
substances
Variable
Composition (it
can change)
Mixture of
substances
Variable
Composition (it
can change)
Can be separated physically
Element
Simplest form of matter that
has unique properties
Element
Simplest form of matter that
has unique properties
Compounds
molecules that contain at least two different
atoms
Compounds
molecules that contain at least two different
atoms Can be separated
chemically
Substance
Definite composition
Substance
Homogeneous
Mixture
Uniform; also
called a solution
Homogeneous
Mixture
Uniform; also
called a solution
Matter Matter Substance Definite composition Substance Definite composition
Mixture of substances
Variable Composition
Mixture of substances
Variable Composition
Homogeneous Mixture
Uniform; also called a solution
Homogeneous Mixture
Uniform; also called a solution
Heterogeneous Mixture Non-uniform Heterogeneous Mixture Non-uniform Element Simplest form of matter that
has unique properties
Element
Simplest form of matter that
has unique properties
Compounds
molecules that contain at least two
different atoms
Compounds
molecules that contain at least two
different atoms
Can be separated physically
Read pages 21-27
