MIDTERM REVIEW
Chemistry
CHAPTER 1
THE SCIENCE OF CHEMISTRY
PG
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4-9
Chemistry – the study of matter and how it
interacts with other matter
Chemical – any substance that has a definite
composition.
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A chemical is always made of the same “stuff” no
matter where it comes from
EXAMPLES OF CHEMICALS
CHEMICALS
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Not all chemicals are bad.
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Chemicals are necessary for every day life.
STATES OF MATTER
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Three states of matter:
Solid
 Liquid
 Gas
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SOLIDS
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Have a fixed volume and definite shape.
Atoms are held tightly in rigid structure and
vibrate only slightly
LIQUIDS
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Have a fixed volume and indefinite shape
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Can easily take the shape if its container
GASES
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Indefinite volume and indefinite shape

Atoms are held very loosely together
PRODUCTS VS REACTANTS
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Products are what come out of a reaction

Reactants are what are put into the reaction
REACTANTS: H2 AND N2
PRODUCT: NH3
DESCRIBING MATTER
SECTION 2
PG
10 -19
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Matter - anything that has mass and volume
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List of non-matter:
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Time
Sound
Sunlight
Thoughts
Gravity
Microwaves
Heat
Memories
Reflections
Energy
VOLUME VS MASS
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Volume – is the amount of space an object takes
up
Mass – the amount of matter in an object
https://www.youtube.com/watch?v=kWpgyn
OgkVE
VOLUME VS MASS
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Volume is measured in liters, gallons, or some
unit cubed (cm3, m3, in3)
Mass is measured in grams
MEASURING VOLUME

Fill a graduated cylinder and read the lines.
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The lines measure mL
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Just like the lines on a ruler measure cm
WHAT IS THE VOLUME OF THIS LIQUID?
WHAT IS THE MASS OF THIS LIQUID?
DETERMINING MASS

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Mass is measured in grams.
To find the mass of something, you must you a
scale or balance.
MASS VS WEIGHT
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Weight is the force produced by gravity acting on
a mass.
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The mass of an object never changes.
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Weight varies depending on gravity.
DENSITY
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Density – is the ratio of mass to volume of an
object.
How much “stuff” is in an object compared to how
much space it takes up.
Density = Mass/Volume
DENSITY
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Density can be used to identify substances
Every pure element has a specific density that
does not change
SECTION 3
HOW IS MATTER CLASSIFIED?
PG 21 -28
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Atoms – the smallest unit of an element that
maintains the properties of that element
PURE SUBSTANCE
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Pure substances are either elements or
compounds.
Pure substances have definite chemical and
physical properties
ELEMENTS
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Are substances that cannot be broken down into
anything else.
Composed of only one type of atom
COMPOUNDS
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Composed of more than one type of atom.
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Still have definite properties.
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Examples :
H2O
 CO2
 C12H6O12
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MIXTURES
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Do not have definite compositions or definite
properties
Examples:
Salt Water
 Sand
 Sugar Water
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HETEROGENEOUS VS HOMOGENEOUS
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Homogeneous – mixture is distributed uniformly
throughout
Heterogeneous – mixture is not distributed
uniformly throughout