Matter

Part II

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Pure Substances vs. Mixtures



Pure Substances

      Made of either elements or compounds that are chemically bonded.

Cannot be separated by physical means.

Glucose: C 6 H 12 O 6 Table Salt: NaCl Oxygen Gas: O 2 Carbon Dioxide CO 2 

Mixtures:

   Two or more substances mixed together but not chemically combined.

  Tea = Crushed Leaf + H 2 O Rocks = minerals + sediments + organic matter  Sugar Water = Sugar + H 2 O Each component retains its own identity; it does not change into something else.

Can be separated by physical means 2

Mixtures

Heterogeneous Mixture

Not evenly mixed Individual components retain their own properties Individual components can be easily seen Can be easily separated Ex.: salt & pepper mix, rocks, cereal, bag of assorted candy

Homogeneous Mixture

Evenly mixed Properties of combined components are usually different than those of each component Individual components can not be easily seen Not as easily separated Ex. salt-water solution, tea, Cool Aid drink, milk, toothpaste 3

Organizing Concepts…

MATTER PURE SUBSTANCE MIXTURE ELEMENTS COMPOUNDS HETERO GENEOUS HOMO GENEOUS

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Choose a partner with the same learning preference as you Classify the following substances as: Pure substance, heterogeneous mixture, or homogeneous mixture

      Gatorade Milk Shake Meat marinade Gasoline Dirt Sulfur       Helium gas Sugar Crystals Fruit Loops Mashed Potatoes Vinegar Air 5

Physical Properties of Matter

 Can be observed without changing a substance into another 

Mass

– amount of matter that something has 

Volume

– amount of space that something takes 

State of matter

– physical forms in which a substance can exist 

Melting point

liquid – temperature at which a substance changes from solid to 

Boiling point

– temperature at which a substance changes from liquid to gas 

Freezing point

– temperature at which a substance changes from liquid to solid 

Density

– the mass of a substance compared to its volume d = m v 6



State of Matter

Determined by the attraction between the particles of a substance, their rate of movement and pressure change.

 Matter changes from one state to another when its energy changes (either loses or gains energy)  Temperature  is a measure of the speed (energy) of the particles of matter Increasing the temperature (energy) of a solid, causes it to change to liquid (melting).

  Increasing the temperature (energy) of a liquid, causes it to change to gas (vaporizing).

The inverse process is also true  http://www.chem.purdue.edu/gchelp/atoms/states.html

State

Solid Liquid Gas Plasma

Volume

Definite Definite Indefinite Indefinite

Shape

Definite Indefinite Indefinite Indefinite

Molecules

Vibrate Slide Bounce Electrons split apart 7

Density

   Ratio between the mass and volume of a substance An object will only float on a liquid if its density is lower than the density of the liquid Predict which objects will float on water:  dry sponge, small rock, large rock, wood block, pencil, oil, ball of modeling clay, modeling class shaped like a bowl, whole lemon, peeled lemon.

 You will find out the correct answers by doing a density lab 8

Chemical Properties of Matter



Describe a change that happens when two substances react with each other

 Ex. rust, burning a match, candle or wood 9

The Periodic Table

 Take the pretest  Go to: http://peachstar.unitedstreaming.com/  Select one of the following videos to watch:     The Periodic Table: Reactions and Relationships  Simply Science: Periodic Table  © 1998 United Streaming Physical Science Series: Atomic Structure and the Periodic Table (17:23) – quiz follows  Discovering the Elements  © 1996 AIMS Multimedia (27:04) (23:30) © 1998 United Streaming (57:12) – Two games follow © 1996 United Learning  Take quiz 10

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Periodic Table

Atomic Number Mass Number or Atomic Mass Carbon 6

C

12.011

Element Name Element Symbol Guided Practice Assignment: Look up the following elements in the periodic table. Draw a box like the one above for each. Identify the atomic number and mass number.

Group 1: H, O, F Group 3: Na, Mg, I Group 2: N, Li, He Group 4: Ca, Cl, K

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A few more…

 Q: Where does one put dirty dishes?

 A: In the “zinc”  Q: What weapon can you make from the elements of potassium, nickel, and iron?

 A: KNiFe  Q: What is the difference between cooking and chemistry?

 A: You should never lick the spoon 14

WEBQUEST

    Choose a partner whose favorite subject is the same as yours (use the This Is Me inventory) Follow the instructions on this website for your assignment: http://web.buddyproject.org/web017/web017/  Read all topics:  History of the Periodic Table    Inside an Atom Reading the Periodic Table Metals, Nonmetals, & Metalloids Choose an element to do your final task and present to your class:  Element ADventure WebQuest You will review and provide feedback to another group’s ad presentation and will be graded on how you do your critique.

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Your Critique

      Read the personal inventory of both members of the group you are to critique Write a letter to the group addressing the good points and not-so-good points of their ad Provide ideas on how they could improve their ad Assign the group a grade for their project Go over your critique with the group explaining your comments Be honest, be fair, be mindful of other students’ feelings 16