States of Matter
Density
Physical and Chemical Properties
Physical and Chemical Changes
Law of Conservation of Mass
Pure Substances
Mixtures
Acids and Bases
Everything that has mass and
volume is called matter.
Mass is a measurement of how much
“stuff” is in an object. Mass is constant
for a given object
Weight is a measure of how much the
gravity on our planet pushes an object
towards its surface. Weight changes
depending on altitude.
physical properties
chemical properties
These changes can be
macroscopic, microscopic, or
submicroscopic.
Macroscopic:
Microscopic:
Submicroscopic:
•Solids
•Liquids
•Gases
•Have a definite shape
•Have a definite volume
•Generally rigid
Particles vibrate close together
with very little movement.
•Have an indefinite shape, so
are fluid.
•Have a definite volume.
Liquid particles vibrate and rotate
around each other.
•Have an indefinite shape and
volume
•Fluid and compressible
Particles vibrate, rotate, and move
randomly through mostly empty
space.
A physical property can be
determined by your senses or by
measuring.
• Physical properties can be divided into
two kinds, intensive and extensive.
• Intensive properties may be used for
identification of unknowns because they
do not change with amount.
• Extensive properties depend on
amount.
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Density
Heat conductivity
Color
Index of refraction
Malleability
•Electrical
Conductivity
•Boiling point
•Melting point
•Ductility
Physical: Density
Density is a ratio that compares the mass
of an object to its volume.
Density =
Mass
Volume
Practice Problem
Suppose a sample of aluminum is placed in a 25 mL
graduated cylinder containing 10.5 mL of water. The
level of the water rises to 13.5 mL. What is the mass
of the aluminum sample? The density of aluminum is
2.7 g/mL.
Known
Unknown
Density = 2.7 g/mL
mass = ?
Volume = 13.5 – 10.5 = 3.0 mL
M
Formula: density = mass/volume or
D= V
Suppose a sample of aluminum is placed
in a 25 mL graduated cylinder containing
10.5 mL of water. The level of the water
rises to 13.5 mL. What is the mass of the
aluminum sample? The density of
aluminum is 2.7 g/mL.
m
D
V
m=DxV
m = 2.7 x 3.0
m = 8.1 grams
Physical: Electrical Conductivity
Physical: Heat Conductivity
Physical: Color
Physical: Melting Point
Physical: Boiling Point
Physical: Index of Refraction
Physical: Malleability
Physical: Ductility
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Color
Boiling point
Density
Melting point
Malleability
Ductility
Conductivity
• Mass
• Volume
• Shape of material
A chemical property involves a
permanent change or reaction.
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Reaction with acid
Reaction with water
Reaction with oxygen
Reaction with base
Ability to burn
Chemical: Reaction w/ Acid
Chemical: Reaction w/ Water
Chemical: Reaction w/ Air
Chemical: Reaction with Base
Chemical: Ability to Burn
Physical
Chemical
Ask yourself, is the change permanent?
Does the matter keep its original
properties?
A physical change is a change
that does not change the identity
of a substance.
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Phase Changes
Melting
Freezing
Cutting
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Dissolving
Breaking
Mixing
Tearing
Ask yourself:
Does the identity of the substance change
or is it just in a different form?
A chemical change is a change that
produces new products. Chemical
changes cannot be reversed by physical
means or chemical means in some
cases.
• Reaction with acids
• Reaction with bases
• Reaction with oxygen
or air
• Rusting
• Burning
• Reaction with other
elements
• Decomposition
• Corrosion
• Spoiling
• Cooking
Look for one or more of the
following:
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Production of a gas
Production of a precipitate
Permanent change in color
Change in temperature
Change in smell
The mass of the reactants before a
reaction is equal to the mass of the
products after the reaction.
In other words, matter cannot be created
nor destroyed. It is just converted from
one form to another
Reactants—the chemicals that react in a
chemical change. They are always on
the left side of a chemical equation.
2H2 + O2 → 2H2O
Products—the chemicals that are formed
in a chemical change. They are always
on the right side of a chemical equation.
2H2 + O2 →
2H2O
Practice Problem
• A 10 g sample of magnesium reacts with
oxygen to form 16.6 g of magnesium
oxide. How many grams of oxygen
reacted?
Magnesium + Oxygen → Magnesium oxide
10 g
+ ___ g =
16.6 g
Kinds of Matter
Mixtures
And
Pure substances
• Fixed composition
• Cannot be separated into simpler substances
by physical methods (physical changes)
• Can only be changed in identity and
properties by chemical methods
• Properties do not vary
Compounds
• Definite Ratio
• Decomposed by
chemical change
Elements
• Cannot be
decomposed by any
changes
Mixtures are two or more substances that
are NOT chemically combined.
Mixtures do not have:
·
constant boiling points
·
constant melting points
• Variable composition
• Components retain their characteristic
properties
• May be separated into pure substances
by physical methods
• Mixtures of different compositions may
have widely different properties
1. Also known as solutions.
2. Look the same throughout
3. Separated by physical means
4. Don’t scatter light
Can’t tell by looking that they are a
mixture.
1. Different components are visible to
the eye
2. Easily separated by physical means
3. Composition varies
• Solutions—particles less than 1nm,
does not scatter light or settle out
• Colloids—particles from 1-1000nm,
shows the Tyndall Effect, does not
settle out
• Suspensions—particles are greater than
1000nm, shows the Tyndall Effect,
settles out
Can be isolated by separation
methods:
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Chromatography (Ink Dye Lab)
Filtration (Sand and Salt Lab)
Distillation
Crystallization
Simple Laboratory Distillation
Apparatus
Electrolytic Solutions
Electrolytes—When you put them into
water, the solution conducts electricity
• Acids—Start with H + nonmetal
• Bases—Metal + end with OH
• Salts—Metal + nonmetal (the
product of a reaction between an
acid and a base!)
Indicators
We can use indicators to show if a solution is an
acid or a base, or use a pH meter.
If the pH = 0-7, the solution is acidic
If the pH = 7-14, the solution is basic
If the pH = 7, the solution is neutral
Indicator
Acid
Base
Litmus
Red
Blue
Phenolphthalein Clear
Pink
Bromothymol
Blue
Blue
Yellow
Common Acids and Bases
Acids:
Citric Acid (in orange juice)
Acetic Acid (vinegar)
Bases:
Ammonia (in cleaners)
Sodium hydroxide (in oven cleaner)