matter - grade 7
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Matter
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Matter
Anything that has mass and takes upspace (volume) Examples:
A brick has mass and takes up space A desk has mass and takes up space A pencil has mass and takes up space Air has mass and takes up space
All of the above examples are considered matter becausethey have mass and take up space. Can you think of anything
that would not be considered matter?
Mass vs. Weight
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Atoms
Smallest possible unit intowhich matter can bedivided, while stillmaintaining its properties
Over 100 different kinds
of atoms exist ( 90 occurnaturally and 25 made inlabs)
Cannot be seen by thenaked eye or even anoptical microscope
Can combine, or bond, tocreate additional types ofmatter
Always moving when abovethe temperature ofabsolute zero
For example, what is thesmallest possible unit
into which a long essay can bedivided and still have some meaning?+
+
+
-
-
--
+
Taking a closer look will reveal thatatoms are composed of smaller parts
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Atoms are so small that
it would take a stack of about50,000 aluminum atoms to equalthe thickness of a sheet ofaluminum foil from your kitchen.
if you could enlarge a penny untilit was as wide as the US, eachof its atoms would be only about3 cm in diameter about thesize of a ping-pong ball
a human hair is about 1 millioncarbon atoms wide.
a typical human cell contains
roughly 1 trillion atoms. a speck of dust might contain3x1012 (3 trillion) atoms.
it would take you around 500years to count the number ofatoms in a grain of salt.
www.deckersfoods.com
C-C-C-C-C- + 999,995 more
1 trillion atoms
.
Is made of approximately 3 trillion atoms
Just one of these grains
http://www.deckersfoods.com/http://www.deckersfoods.com/ -
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Lets Experiment
In order to try to gain an idea of how smallan atom really is, you will complete thefollowing activity.
1. Cut a strip of 11 in. paper in half.2. Place one half on the table.3. Cut the remaining piece in half.4. Continue cutting and placing the strips on the
table as many times as you can.5. Make all cuts parallel to the first one.
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Results
How many cuts were you able to make?
Do you think you could keep cutting the
paper forever? Why or why not?
You would have to cut the paper inhalf around thirty-one (31) times to
get to the size of any atom.
http://www.miamisci.org/af/sln/phantom/papercutting.html
http://www.miamisci.org/af/sln/phantom/papercutting.htmlhttp://www.miamisci.org/af/sln/phantom/papercutting.html -
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Combining Atoms
There are over one hundred different types of atomsand they oftentimes combine to make new substancesknown as molecules and compounds
MoleculeResults from the
bonding oftwo or more atoms
CompoundA substance that
contains two or moredifferent elements
(atoms)
Compounds are molecules but not all molecules are compounds
Example Oxygen Gas (O2) Example Water (H2 O)
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Building Molecules/Compounds
Use the molecular model kit to build the followingmolecules/compounds
H O - H
H
H
C
H
H
HC
H
H
H C
OH
H
C
H
OH
HC
H
O
C
OH
H
C
H
OH
C
H
OH
C
Water
Propane Glucose
O O
Oxygen Gas Which ofthese aremolecules?
Compounds?Both?
Structural DiagramsShow atomic
arrangement ofmolecule/compound
Chemical SymbolAbbreviation for the
element/atom
Chemical BondLink holding
atoms together
Build a Molecule
http://phet.colorado.edu/en/simulation/build-a-moleculehttp://phet.colorado.edu/en/simulation/build-a-molecule -
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Molecule, Compound, or Both?
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Combining Molecules/Compounds
a combination of two or more substancesthat do not combine chemically, butremain the same individual substances is
known as a mixture can be separated by physical means
two types
Heterogeneous Homogeneous
Based on the prefixeshetero and homo,what do you think are
characteristics of thesetwo types of mixtures?
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Creating Mixtures Part 1
Pour cup A into cup B and mix the contentswith a glass stirring rod.
Observations/Questions
Describe what you see in the cup. Draw a picture of what you see in the beaker.
Using any means necessary, try to separate themixture back into its original parts. Was it
possible to separate the mixture? Why or whynot?
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Heterogeneous Mixture
Hetero means different consists of visibly different substances or
phases (solid, liquid, gas) a suspension is a special type of
heterogeneous mixture of larger particlesthat eventually settle
Example:
Trail MixNotice thevisiblydifferent
substances
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Creating Mixtures Part 2
Pour cup C into cup D and mix the contentswith a glass stirring rod.
Observations/Questions
Describe what you see in the cup. Draw a picture of what you see in the beaker.
Using any means necessary, try to separate themixture back into its original parts. Was it
possible to separate the mixture? Why or whynot?
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Homogeneous Mixture
Homo means the same
has the same uniform appearance andcomposition throughout; maintain one phase
(solid, liquid, gas) commonly referred to as solutions
Example:
Salt WaterNotice the
uniformappearance
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Physical Properties of Matter
any property of matter that can be observedor measured without changing the identity ofthe matter
Examples colorshapetaste
state/phasedensity D = m
V
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Chemical Properties of Matter
any property of matter that describes asubstance based on its ability to changeinto a new substance
Examplesflammability
reactivity with vinegar
reactivity with oxygen
Iron + Oxygen Iron oxide (rust)2Fe + 3O2 Fe2O3
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Chemical or Physical Property?
1. Paper is white
2. Boiling point of H2O is 100oC
3. Zinc reacts with hydrochloric acid and createshydrogen gas
4. Nitrogen does not burn
5. Sulfur smells like rotten eggs
Physical Property
Physical Property
Physical Property
Chemical Property
Chemical Property
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Comparing Physical and ChemicalProperties
Substance/Matter Physical Property Chemical Property
Helium Less dense than air NonflammableWood Grainy texture Flammable
Baking soda White powder Reacts with vinegar to producebubbles
Powdered sugar White powder Does not react with vinegar
Rubbing alcohol
Clear liquid
Flammable
Red food coloring Red color Reacts with bleach and losescolor
Iron Malleable Reacts with oxygen
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Physical Change
a change in shape, size, color, or state a change without a change in chemical
composition a change that is reversible
The Mixtures Lab Examples
tearing paper
cutting your hairchange in state
http://www.harcourtschool.com/activity/mixture/mixture.htmlhttp://www.harcourtschool.com/activity/mixture/mixture.html -
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Changes in States(Physical Changes)
Melting
Vaporization
(Evaporation/Boiling)
Freezing
Condensation
All changes in state require achange in energy
Sublimation
Bose-Einstein
Solid
Liquid
Gas
Plasma
Disposition
Why do you think Bose-Einstein andplasma are not equally distanced from
the other three states of matter?
Ionization
Recombination
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Phase Changes Simulation
PhET
Harcourt School Pearson
This is what happens when energy is addedand/or taken away from matter
http://phet.colorado.edu/en/simulation/states-of-matterhttp://www.harcourtschool.com/activity/states_of_matter/index.htmlhttp://www.media.pearson.com.au/schools/cw/au_sch_whalley_sf1_1/int/2_slg.htmlhttp://www.media.pearson.com.au/schools/cw/au_sch_whalley_sf1_1/int/2_slg.htmlhttp://www.harcourtschool.com/activity/states_of_matter/index.htmlhttp://phet.colorado.edu/en/simulation/states-of-matter -
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Chemical Change
a change in which a substance becomes anothersubstance having different properties
a change that is not reversible using ordinaryphysical means
Changes that usually cause heat, sound, light, odor,fizzing/foaming, color changesYou usually need more than one of the above
characteristics to be considered a chemicalchange!
Examplescombining sulfuric acid and sugar
burning a piece of woodsoured milk
http://www.youtube.com/watch?v=nqDHwd9rG0shttp://www.youtube.com/watch?v=nqDHwd9rG0s -
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Chemical or Physical Change?
1. Bending a Paper Clip
2. Baking a cake
3. The sublimation of carbon dioxide
4. Crushing an aluminum can
5. Vinegar and baking soda combining to create salt andwater
Physical Change
Chemical Change
Chemical Change
Physical Change
Physical Change
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Mass vs. Weight
Mass
a measure of how muchmatter an object is made of
does not change, regardless
of where something orsomeone is
Weight
the force of gravity on anobject
equal to the mass of the
body times the localacceleration of gravity
http://www.exploratorium.edu/ronh/weight/index.html
Why do youthink thepersons
weight isless on the
moon?Mass = 59 kg Mass = 59 kg
Weight = 579 N Weight = 96 N
http://www.exploratorium.edu/ronh/weight/index.htmlhttp://www.exploratorium.edu/ronh/weight/index.html -
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Element
A pure substance made up of one kind of atom cannot be broken down or separated into simpler
substances by physical or chemical means Over 100 kinds of elements exist
90 occur naturally on Earth 25 were made by scientists in labs
http://www.privatehand.com/flash/elements.html
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5 Physical States of Matter
Bose-Einstein
Solid Liquid
Gas Plasma
(Newest State)
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Bose-Einstein Condensate
Exist at extremelycold temperatures(around absolute zeroor -460 oF)
Particles are superunexcited
Particles lock orclump together sofirmly that they moveas a single unit
Definite shape andvolume (?)
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Solid
Particles aretightly compact
Particles vibratewithout the abilityto move freely
Definite shape andvolume
Solid Animation
http://www.visionlearning.com/library/flash_viewer.php?oid=1435&mid=120http://www.visionlearning.com/library/flash_viewer.php?oid=1435&mid=120 -
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Liquid
Particles aretightly compact,but able to movearound close toeach other
No definite shape,but definitevolume
Liquid Animation
http://www.visionlearning.com/library/flash_viewer.php?oid=1434&mid=120http://www.visionlearning.com/library/flash_viewer.php?oid=1434&mid=120 -
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Gas
Particles can easilyspread out or moveclose together
Particle movefreely and with alot of energy
No definite shapeor volume Gas Simulation
http://www.visionlearning.com/library/flash_viewer.php?oid=321&mid=120http://www.visionlearning.com/library/flash_viewer.php?oid=321&mid=120 -
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Plasma
Exist at extremely hightemperatures (severalmillion degrees Celsius)
Particles are broken apart
Particles move freely andwith extremely high energy This form is not too common
on Earth, however it is themost common form ofmatter in the universe
No definite shape orvolume?
Examples: Florescent andneon lights, lightning, auroraborealis
Why do you think this is themost common form/state of
matter in the universe?
http://www.geo.mtu.edu/weather/aurora/http://www.geo.mtu.edu/weather/aurora/http://www.geo.mtu.edu/weather/aurora/http://www.geo.mtu.edu/weather/aurora/http://www.geo.mtu.edu/weather/aurora/http://www.geo.mtu.edu/weather/aurora/http://www.geo.mtu.edu/weather/aurora/ -
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Energy and the States of Matter
The physical states of matter result from the amountof energy the particles composing the matter have.Basically, more energy means more movement for theparticles and less energy means less movement.
Energy/Temperature and Matter Simulations PhET BEC: Temperature and Absolute Zero
If you were to compare an ice cube and the steam createdfrom boiling water, which would you think has more energy?
http://phet.colorado.edu/en/simulation/states-of-matterhttp://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/physics/PhysicsInitiative/Physics2000/bec/temperature.htmlhttp://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/physics/PhysicsInitiative/Physics2000/bec/temperature.htmlhttp://phet.colorado.edu/en/simulation/states-of-matter -
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States of Matter Continuum
Taken from: http://www.chem4kids.com/files/matter_becondensate.html
What about this continuum couldbe considered a little misleading?
http://www.chem4kids.com/files/matter_becondensate.htmlhttp://www.chem4kids.com/files/matter_becondensate.html -
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Density
a measure of the amount of matter present in a givenvolume of a substance
typically expressed in the following units: grams per cubic centimeter (g/cm3) for solids grams per milliliter (g/ml) for liquids
does not depend on how much of a substance you have(intrinsic property) in other words, the density of agold bar would be the same as the density of a goldflake
can change as temperature and pressure change
Which do you thinkis more dense? Why?
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Layering Liquids
Using a test-tube and the eyedroppers, try to layer the four differentcolored liquids so that the colors dont mix and show distinct layers.
1. Hold the test-tube in your hand at a 45 degree angle.2. Using the eyedropper from one of the colors, slowly place the
liquid into the test-tube.3. Repeat step two using the other three liquids until you get themlayered. Record the order of the colors.
If you dont get clear separation of the colors, you should empty thecontents of the test tube down the drain and start again. These steps
may need to be repeated several times until you discover the correctorder of the colors.
*Placing white paper behind the straws will help yousee the divisions
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Layering Liquids - Discussion
1. Were you capable of layering the four liquids? Ifso, what was the correct order from the bottom up?
2. What difficulties did you experience whenperforming this activity?
3. Why do you think the liquids created layers whenputting them in the test tube in the correct order?
4. Because these liquids are miscible, or partiallymiscible, they did not really create distinct layers.What do you think it means to be miscible?
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Calculating Density
Density can be calculated by dividingthe mass of an object by its volume
D = mV
Sample ProblemTimothy found a solid metal block
that has a mass of 100 grams and
a volume of 25 cm3. What would be
the density of the block?
D = =100 grams25 cm3
4 gramscm3
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Practice Problems
1. Find the density of a substance with a mass of27 g and a volume of 7 cm3.
2. A block of maple has a mass of 20 grams and a
volume of 26.5 cm3
. What is the density of theblock?
D = mV
D = mV
D = =27 g7 cm3 3.86 gramscm3
D = 20 grams26.5 cm3
=0.75 grams
cm3
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The Density Triangle
D V
m
.
D = mV
V = mD
m = D V.