MATTER AND ENERGY

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MATTER AND ENERGY
Dark matter, matter we cannot see. Perhaps it
doesnt have or emit light. Scient..ists look at
galaxy clusters and determine the amount of
gravity holding the cluster together. From this
information they can determine mass. They find
there is a great deal more mass than they can
account for from the visible material, thus the
proposed existence of a new kind of matter,
dark matter..
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• MATTER
• PART I
• CLASSIFYING MATTER

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The Study of matter and how it changes
is

• Matter is anything having mass and volume.

Mass- the amount of matter in an object
CHEMISTRY

• Mass is measured with a balance, unit is grams
• mass is related to weight but isnt the same
  thing.
• weight is dependent upon gravity.
• mass never changes

Volume- anything that takes up space, unit L,
cm3, mL
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IS AIR MATTER?
Does air have mass?
Does air have volume?
YES, to both, so air is matter
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PROPERTIES OF MATTER

• Composition- what matter is made of. Water is
  made of hydrogen and oxygen (H2O), tea has
  caffeine
• Properties-what matter is like. For example,
  water can dissolve many substances and caffeine
  is a stimulant.

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UEQ In dealing with matter, how are composition,
structure, properties and energy related? LEQ
What are the differences between physical and
chemical properties?

• Extensive properties

• Intensive properties

• Depends on the amount of matter present
• Volume, mass, amount of energy in a substance

• Does not depend on amount of matter present
• Melting point, boiling point, density, ability to
  conduct electricity and transfer energy as heat

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UEQ In dealing with matter, how are composition,
structure, properties and energy related? LEQ
What are the differences between physical and
chemical properties?

• Physical changes

• Chemical changes

• Change that does not change the identity or
  chemical makeup of the substance
• Cutting, melting, drawing into wire, crushing,
  temperature and pressure changes

• Substance changes into new substance b/c chemical
  bonds have been broken or made
• Occurs on molecular level
• Noticed by temperature change, smell/odor,
  bubbles (gas), rust formation
• Reactants ?products

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THE BASIC UNIT OF MATTER IS AN ATOM
There are over 118 varieties of atoms
PERIODIC TABLE
http//www.webelements.com/scandium/
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ELEMENTS contain only one type of atom. Ex
hydrogen (H) is an element that contains only
hydrogen atoms, carbon (C) contains only carbon
atoms, oxygen (O) contains only oxygen atoms,
etc. Atoms of elements can combine together to
form compounds. COMPOUNDS are neutral groups of
atoms held together by chemical bonds. Ex CO2,
H2O, H2, O2
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HOW DO WE CLASSIFY MATTER?

• All matter is classified as either a pure
  substance or a mixture

Alloy rims/ mixture of two metals
Pure gold/Pure substance
24 karat
18 karat
End of introductory material. Return to index
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CLASSIFYING MATTER

• Pure substance-a type of matter where all
  samples, no matter how big or small, have the
  same propertiesthey behave in exactly the same
  way.
• Elements
• Compounds

Elements contain one type of atom, thus they
CANNOT be broken down into simpler substances by
chemical means.

• Elements consist of either
• single atoms, such as Carbon (C), or Sodium (Na)
• groups of atoms of the same type (molecules),
  such
• as H2, O2, Br2, etc.

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ELEMENTS
MONATOMIC ELEMENTS
DIATOMIC ELEMENTS
ALLOTROPES
Atomic nitrogen N Molecular nitrogen N2
Ozone O3 Atomic hydrogen H Molecular
hydrogen H2 Graphite, buckyball
Atomic oxygen O Molecular oxygen O2 Carbon
C
ALLOTROPE-different forms of an element in same
physical state
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COMPOUNDS

• Compounds are substances made up of 2 or more
  different
• elements that are chemically combined. CO2,
  H2O, HCl, Na2SO4
• COMPOUNDS CAN BE BROKEN DOWN INTO SIMPLER
  SUBSTANCES BY CHEMICAL MEANS ONLY.
• COMPOUNDS HAVE DIFFERENT PROPERTIES THAN THE
  ELEMENTS THAT MAKE THEM UP.
• Click on the links below to watch videos of
  compounds broken down into the substances that
  make them up.

• Example-hydrolysis of water 2H2O ? 2H2
  O2
• water breaks down into the hydrogen and oxygen
  gas which make it up.
• http//www.all-science-fair-projects.com/science_f
  air_projects/38/819/5db524216341764c1438c1f760fddf
  f8.html
• http//earth2tech.com/2008/07/31/mit-solar-energy-
  storage-breakthrough/

• Example-dehydration of sugar C12H11O22? 12C(s)
  11 H2O(g)
• Sugar breaks down into carbon and water

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ELEMENTS TO COMPOUND
COMBINED WITH
Will Form
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TABLE SALT!
Sodium metal and chlorine gas, under the right
conditions, undergo a chemical change and combine
to become..
2 Na(s) Cl2(g) ? 2 NaCl
The final compound has properties different from
the elements that formed it.
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REVIEW

1. We are studying CHEMISTRY, the study of
   ________and how it ________.
2. Matter is anything that has___ and takes up ___.
3. ___ are the basic building blocks of matter.
4. Matter can be classified as either a ___ or a
   ___.
5. Substances are either ___ or ___.

Answers
1. matter, changes 2. mass, space 3. atoms 4.
pure substance, mixture 5. elements, compounds
Return to index
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THUS FAR WE HAVE REVIEWED MATTER AS PURE
SUBSTANCES.
NOW LETS DISCOVER MATTER AS MIXTURES
MATTER
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MATTER AS MIXTURES

• Mixtures are combinations of 2 or more
  substances where each substance retains its
  individual properties.

HOW ARE MIXTURES LIKE COMPOUNDS?
THEY ARE MADE FROM TWO OR MORE SUBSTANCES
HOW ARE MIXTURES DIFFERENT FROM COMPOUNDS?
MIXTURES DO NOT FORM CHEMICAL BONDS.
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Classifying mixtures
There are two types of mixtures
1) HOMOGENEOUS
2) HETEROGENEOUS
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a mixture that is the same throughout. A
homogeneous mixture has a composition and
properties that are identical regardless of the
sample
is
Ways to identify a homogeneous mixture
HOMOGENEOUS
A SOLUTION is another name for a homogeneous
mixture
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a mixture that is visibly different throughout.
Heterogenous mixtures have a composition and
properties that differ in any given sample.
is
Ways to identify a homogeneous mixture
HETEROGENEOUS
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HETEROGENEOUS MIXTURES

• There are special types of heterogeneous
  mixtures
• Suspensions-appear uniform when mixed but settle
  out.
• Chocolate Quik
• Muddy water
• Pulpy oj
• Oil Vinegar dressing
• Colloids-appear uniform but they do not settle
  out. However, their particles are too large to
  be classified as a homogeneous solution.
• Gelatin
• Milk
• Smoke
• Fog
• mayonnaise

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TYNDALL EFFECT

• Colloids are evenly mixed, but their particles
  are too large to be considered homogeneous
  mixtures, which are also the same throughout.

Colloids show the Tyndall Effect. The Tyndall
effect is the scattering of light as a beam
passes through a colloid.
In each picture, the colloid on the left scatters
the beam making it visible
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MixturesSummary
Heterogeneous Mixture Homogeneous Mixture
Not evenly mixed Evenly mixed
Individual components retain their own properties Properties of combined components are usually different than those of each component
Individual components can be easily seen Individual components can not be easily seen
Can be easily separated Not as easily separated
Ex. salt pepper mix, rocks, cereal, bag of assorted candy Ex. salt-water solution, tea, Cool-Aid drink
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Practice Problems
Determine whether each is a heterogeneous or
homogeneous mixture

• Tossed salad
• Salt water
• Kool-aid
• Muddy water
• OJ with pulp

6. Tea 7. Banana nut bread 8. Pizza 9.
Blood 10. Brass
1. He 2. Ho 3. Ho 4. He 5. He 6. Ho 7. He 8. He
9. He 10. Ho
Answers
Return to index
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Now, lets put it all together and determine how
to tell substances (compounds and elements) from
mixtures.

• Pure Substances
• Made of either elements or compounds that are
  chemically bonded.
• Cannot be separated by physical means.
• When combined they take on new properties
  different from the original elements.
• Examples
• Glucose C6H12O6
• Table Salt NaCl
• Oxygen Gas O2
• Carbon Dioxide CO2

• Mixtures
• Two or more substances mixed together but not
  chemically combined.
• Tea Crushed Leaf H2O
• Rocks minerals sediments organic matter
• Sugar Water Sugar H2O
• Each component retains its own identity it does
  not change into something else.
• Can be separated by physical means
• Examples
• Sweet tea
• Trail mix
• Air (O2, N2, CO2, Ar)

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Elements, Compounds, and Mixtures

1. Two types of atoms evenly mixed
2. Two types of atoms chemically combined
3. One type of atom
4. Two types of atoms mixed
5. An element
6. A solution
7. A compound
8. A mixture

Two of the descriptions to the right apply to
each bottle below. Determine the appropriate
descriptions.
d h
b g
c e
a f
2_______
1_______
3_______
4_______
Return to Index
Dorin, Demmin, Gabel, Chemistry The Study of
Matter , 3rd Edition, 1990, page 68
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Classifying Matter
Review How matter is classified
Matter
Pure Substances
Mixtures
Homogeneous
Heterogeneous
Elements
Compounds
Rocky Road ice cream, muddy water
Tea, kool-aid
He, O
H2O, NaCl
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Classify the following substances asPure
substance, heterogeneous mixture, or homogeneous
mixture
More review
Return to index