Working with the Properties and Changes of Matter

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Working with the Properties and Changes of Matter
General Chemistry
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What is Chemistry ?!

• Whats a chemical?
• Any substance that has a definite
  composition.
• Why study this stuff?
• To be able to use the information to your
  benefit.
• Whats a chemical reaction?
• A change in the chemical structure of a
  substance.
• Is this gonna be difficult ?
• Thats up to you

S1T2C6
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You depend on chemicals everyday !JUST TO NAME
A FEW

• Water DEET
• Polyethylene ingredients in toothpaste
• Carbon Dioxide acetylsalicylic acid
• Oxygen nitrogen
• Niacin acetylene
• Sucrose polyester
• Aluminum silicon dioxide
• Cellulose calcium carbonate

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So Where does Chemistry fit in ?

• Biology matter that is alive
• Chemistry how matter is put together
• how atoms combine to form
  molecule
• how molecules combine to make
  different kinds
• of matter
• Physics The nature of basic things such as
  motion, forces,
• energy, matter,
  heat, sound, light the composition of
• atoms.

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So, What is Matter ?

• Matter is defined as anything that has
• Mass (inertia
• a resistance to change in
  movement
• Takes up space (volume)

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Physical States of MatterTheres 4 of them !

• SOLIDS
• Have definite (or fixed) shape and volume
• The particles in a solid are held fairly
  rigidly in place.

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Physical States of MatterTheres 4 of them !

• LIQUIDS
• Have a definite volume but no fixed shape.
• The particles in a liquid are free to flow
  around each other

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Physical States of MatterTheres 4 of them !

• GASSES
• Have neither definite or fixed shape or
  volume.
• The particles in a gas are widely
  disbursed,
• 
  interact weakly,
• move
  independently at high speed,
• and completely fill any
  container they occupy.

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Physical States of MatterTheres 4 or more of
them !

• PLASMAS
• Gases whose particles are so hot they have
  acquired an electrical charge.
• Bose-Einstein Condensates
• Groups of atoms at such low temperatures that
  they behave as a single unit or super atom.
  (0.001 K)
• Neutron Stars
• Matter that has collapsed due to gravity to leave
  nothing but a pile of neutrons touching each
  other with no space in between. (about 78,000
  tons per teaspoon)

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Changes in Matter .

• Physical Changes
• Changes in which the basic identity of
  the substance does not change.
• The physical state (solid, liquid, or
  gas) may change
• Examples
• Salt or sugar dissolving in water
• wax melting in a candle
• crushing a rock

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Changes in Matter .

• Chemical Changes
• There is a change in the identities of the
  substances
• and new substances with different identities
  are formed.
• Example
• mercury(II) oxide mercury
  oxygen (gas) sodium iodide lead nitrate
  lead iodide sodium nitrate

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Changes in Matter .

• In any reaction
• Left side Right side
  
• 
  
• Methane oxygen forms carbon dioxide water
  vapor
• REACTANTS PRODUCTS
• Used up in the reaction Produced in
  the reaction
• The reactants and products are THE SAME atoms
  just rearranged as time has passed.

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Evidence of a chemical change

• The evolution of a gas
• evidenced by bubbling or a change in color
• The formation of a precipitate
• A solution turns cloudy or a solid drops
  out of solution
• The release or absorption of energy
• The temperature changes either hotter or
  cooler
• or the solution or substance glows!
• A color change

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Elements, Compounds, and Mixtures

• Elements are pure substances
• composed of only one type of matter
• Compounds are substances made
• up of more than one type of matter
• acting like a single pure substance.
• Mixtures are made up of more than
• one substance in which each part
• Retains its chemical identity.

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ELEMENTS

• Elements can be found as single ATOMS
• EXAMPLE He, Ne, Ar, Kr, Ra
• Elements can be found as MOLECULES made up of 2
  or more atoms of the same substance.
• EXAMPLE H2, O2, N2, F2, Cl2, Br2, I2
• Some elements have more than one form and are
  called ALLOTROPES.
• EXAMPLE Oxygen, Phosphorus, Sulfur, Carbon

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Allotropes

• Oxygen Oxygen O2 and Ozone O3
• Phosphorus Red and White Phosphorus
• Sulfur Yellow S8
• Carbon soot, graphite, diamond, and fullerines
  (C60) or nanotubes

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COMPOUNDS

• Compounds are pure substances
• They are represented by formulas
• Molecular formulas tell what elements and how
  much of each element is present
• EXAMPLE C12H22O11 ? (Hint
  Its sweet!)
• Structural formulas show how the atoms are
  connected

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MIXTURES

• Mixtures are physical combinations of substances.
• Each part retains its chemical identity.
• Mixtures can vary in composition and properties.
• A mixture of metals is called an ALLOY
• EXAMPLES gold in jewelry is mixed with
  silver, copper or nickel to add strength and wear
  resistance.
• Copper and zinc make brass
• Copper and tin make bronze

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Types of Mixtures

• Homogeneous Mixtures - physical combinations of
  substances in which the components are UNIFORMLY
  DISTRIBUTED
• Heterogeneous Mixtures - physical combinations
  in which the substances are UNEVENLY DISTRIBUTED

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Types of Mixtures

• EXAMPLES
• Homogeneous solutions
• tea, stainless steel, 14 kt gold,
  maple syrup
• Heterogeneous Colloids and suspensions
• Orange or Tomato juices fog
• Chocolate chip cookies shaving cream
• Granite
  jello or gelatin
• Salads
  clouds

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Mixtures and Compounds

• Mixtures can be separated by physical methods
• Chemical methods must be used to separate
  compounds
• The components of a mixture can be present in
  varying proportions
• Compounds have DEFINITE proportions of the
  elements that make them up

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Separating Mixtures

• Physical properties are exploited to separate the
  substances in a mixture.
• Boiling point used in
  petroleum refining
• Solubility used in
  purifying salt etc.
• Melting point used in
  metallurgy
• Density used in gold
  mining
• Magnetic suseptability used in iron and
  nickel
• Chemical reactivity used in purifying

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SUMMARY

• Matter has mass and
  volume
• can be
  can be
• Pure Substances Mixtures
• Element Compound Heterogeneous
  Homogeneous
• Gold methane suspensions
  colloids solutions
• Mercury ammonia mud puddle
  smog coffee
• Nitrogen proteins salad
  whipped cream tea
• Silicon salt
  sandwitch gel Koolade