Matter - Grade 7

7/29/2019 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
http://www.privatehand.com/flash/elements.htmlhttp://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


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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


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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.

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Matter - Grade 7