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Table of Contents. 15. The Nature of Matter. Chapter 15: Classification of Matter. 15.1: Composition of Matter. 15.2: Properties of Matter. 15.3: Physical vs. Chemical Changes. 15.4:. Composition of Matter. 15.1. Pure Substances. Materials are made of a

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slide1

Table of Contents

15

The Nature of Matter

Chapter 15: Classification of Matter

15.1: Composition of Matter

15.2: Properties of Matter

15.3: Physical vs. Chemical Changes

15.4:

slide2

Composition of Matter

15.1

Pure Substances

  • Materials are made of a
  • pure substance or a
  • mixture of substances.
  • A puresubstance, or simply a substance, is a type of matter with a fixed composition.
  • A substance can be either an
  • element or a compound.
slide3

Composition of Matter

15.1

Elements

  • All substances are built from atoms. If all the atoms in a substance have the same identity, that substance is an element.
  • The graphite in your pencil point and the copper coating of most pennies are examples of elements.
substances
Elements Substances
  • Compounds

H O K

He N B

Na S P

Li Cu Be

C Au Ar

H2O

NaCl

CO2

HCl

elements
ELEMENTS- SIMPLEST FORM OF A PURE SUBSTANCE

Elements  CAN NOTBE CHANGED INTO SIMPLER SUBSTANCES BY HEATING OR BY ANY CHEMICAL PROCESS

- SMALLEST PART IS CALLED AN _____

*Which means – Uncutable or Indivisible

Elements

ATOM

atoms
- ALL ATOMS OF THE SAME ELEMENT

ARE ALIKE

- ATOMS OF DIFFERENT ELEMENTS

ARE DIFFERENT

- EACH ELEMENT IS REPRESENTED BY

A CHEMICAL SYMBOL

Atoms
chemical symbols
ARE A SHORTHAND WAY OF

REPRESENTING AN ELEMENT

CHEMICAL SYMBOLS

Symbols are always written with first letter capitalized and if there is a second letter is will always be lower case

C : CARBON H : HYDROGEN

Na : SODIUM O : OXYGEN

Cl : CHLORINE Au : GOLD

He : HELIUM N : NITROGEN

Ne : NEON Pu : PLUTONIUM

Es : EINSTEINIUM Eu : EUORPIUM

LATIN NAMES, FAMEOUS SCIENTIST, PLACES, PLANETS, AND COUNTRIES ARE OFTEN USED TO CREATE AN ELEMENT SYMBOL

slide8

Elements

  • More than 20 others have been made in laboratories, but most of these are unstable and exist only for short periods of time.

About 92 elements are found on Earth.

compounds
Compounds

COMPOUNDS - PURE SUBSTANCES MADE UP OF MORE THAN ONE ELEMENT

Joined in the same RATIO

Exp: Water (H2O),Carbon Dioxide (CO2),

compounds1
CAN BE BROKEN DOWN INTO SIMPLER SUB.S’ !!!

PROPERTIES OF COMPOUNDS ARE DIFFERENT THAN THE PROPERTIES OF THE ELEMENTS IN THEM:

NaCl Table Salt

Compounds

*MOLECULES - MAKE UP MOST COMPOUNDS

- TWO OR MORE ATOMS CHEMICALLY BONDED

TOGETHER

molecules cont
- IS THE SMALLEST PART OF A COMPOUND WITH ALL THE PROPERTIES OF THAT COMPOUND

-ALL MOLECULES OF THE SAME COMPOUND ARE ALIKE

Molecules cont.
slide12

Composition of Matter

15.1

Compounds

  • Can you imagine yourself putting something made from a slivery metaland a greenish-yellow, poisonous gas on your food?
slide13

Composition of Matter

15.1

Compounds

  • Table salt is a chemical compound that fits this description. Even though it looks like white crystals and adds flavor to food, its components—sodium and chlorine—are neither white nor salty.
slide14
Mixtures

MATTER THAT CONSIST OF TWO OR MORE SUBSTANCES MIXED TOGETHER

BUT

NOT

CHEMICALLY COMBINED !!!

which is which substance or mixture
Which is Which ?Substance or Mixture

    When you see distilled water, it's a pure substance. That fact means that there are just water molecules in the liquid.

the tap water is the m i x t u r e and distilled water is a substance which is a type of compound
The tap water is the mixtureand Distilled water is a Substance  which is a type of Compound
mixtures background info
There are an infinite number of mixtures.

Anything you cancombineis a mixture.

(even the above sentence is a mixture.)

Don’t copy the statement below in yellow just read it.

Think of everything you eat. Just think about how many cakes there are. Each of those cakes is made up of a different mixture of ingredients. Even the wood in your pencil is considered a chemical mixture. There is the basic cellulose of the wood, but there are also other compounds in that pencil.

Mixtures – Background Info
slide18

15.1

Mixture

  • A Mixture, such as the pizza or soft drink shown, is a material made up of two or more substances that can be easily separated by physical means.
slide19

Composition of Matter

15.1

Heterogeneous Mixtures

  • Unlikecompounds, mixtures do not always contain the same proportions of the substances that make them up.
  • A mixture in which different materials can be distinguished easily is called a heterogeneous (he tuh ruh JEE nee us) mixture.

HETEROGENEOUS MIXTURE - DOES NOT APPEAR TO BE THE SAME THROUGHOUT

slide20

Composition of Matter

15.1

Heterogeneous Mixtures

  • Most of the substances you come in contact with every day are heterogeneous mixtures. Some components are easy to see, like the ingredients in pizza, but others are not.
  • For example, the cheese in pizza is also a mixture, but you cannot see the individual components.
slide21

Composition of Matter

15.1

Homogeneous Mixtures

  • Soft drinks contain water, sugar, flavoring, coloring, and carbon dioxide gas.
  • Soft drinks in sealed bottles are examples of homogeneous mixtures.

Steel is a homogeneous mixture

slide22

Homogeneous Mixtures

  • A homogeneous(hoh muh JEE nee us)mixturecontains two or more gaseous, liquid, or solid substances blended evenly throughout.

oil or vineagar is an example of a homogeneous mixture wherein the composition is uniform throughout the entire thing

slide23

Composition of Matter

15.1

Homogeneous Mixtures

  • Another name for homogeneous mixtures like a cold soft drink is solution.
  • A solution is a homogeneous mixture of particles so small that they cannot be seen with a microscope and will never settle to the bottom of their container.
slide25

Composition of Matter

15.1

Colloids

  • Milk is an example of a specific kind of mixture called a colloid.
  • A colloid(KAH loyd) is a type of mixture with particles that are larger than those in solutions but not heavy enough to settle out.
slide26

Examples of colloids

  • These are just a few of the many examples of colloids, both man-made and naturally occuring.
  • Aerosols:
    • Man-made: Aerosol sprays, insecticide spray, smog. Natural: Fog, clouds.
  • Solid aerosol:
    • Natural: Smoke, dust.
  • Foam:
  • Man-made: Shaving lather, whipped cream.
  • Emulsions:
    • Man-made: Mayonnaise, cosmetic lotion, lubricants. Natural: Milk.
  • Sols:
    • Man-made: Paint, ink, detergents, rubber (a latex - also occur naturally).
  • Solid foams:
    • Man-made: Marshmallow, styrofoam, insulation, cushioning.
  • Gels:
    • Man-made: Butter, jelly.
  • Solid sols:
    • Man-made: Certain alloys. Natural: Pearl, opal
slide27

Detecting Colloids

  • One way to distinguish a colloid from a solution is by its appearance.
  • Fog appears white because its particles are large enough to scatter light.
  • Sometimes it is not so obvious that a liquid is a colloid.
  • You can tell for certain if a liquid is a colloid by passing a beam of light through it.
slide28

Composition of Matter

15.1

Detecting Colloids

  • A light beam is invisible as it passes through a solution, but can be seen readily as it passes through a colloid. This occurs because the particles in the colloid are large enough to scatter light, but those in the solution are not.
  • This scattering of light by colloidal particles is called the Tyndall effect.
slide30

Guess what this is and get a sticker!

You must raise your hand.

slide31

Suspensions

  • Some mixtures are neither solutions nor colloids. One example is muddy pond water.
  • Pond water is a suspension, which is a heterogeneous mixture containing a liquid in which visible particles settle.
  • Fine sand in water
  • Paint
  • Dust in air
  • droplets of oil in air
  • oil and waterfine
  • Italian Dressing

Some examples:

slide32

Composition of Matter

15.1

Suspensions

  • The table summarizes the properties of different types of mixtures.
slide34

Composition of Matter

15.1

Homogeneous Mixtures

  • Solutions remain constantly and uniformly mixed.
slide35

Section Check

15.1

Question 1

A _______ is a type of matter with a fixed composition.

A. colloid

B. mixture

C. substance

D. solution

slide36

Section Check

15.1

Answer

The answer is C. A substance can be either an element or a compound.

slide37

Section Check

15.1

Question 2

How many elements are found on Earth?

A. 5

B. 10

C. 30

D. 90

slide38

Section Check

15.1

Answer

The answer is D. About 92 elements are found on Earth, and more than 20 have been made in laboratories.

slide39

Section Check

15.1

Question 3

How are compounds different from mixtures?

slide40

Section Check

15.1

Answer

The atoms in compounds are combined in fixed proportions and cannot be separated by physical means. A mixture is made of two or more substances that can be easily separated by physical means.

slide42

Properties of Matter

15.2

Physical Properties

  • Any characteristic of a material that you can observe without changing the identity of the substances that make up the material is a physicalproperty.
  • Examples of physical properties are color, shape, size, density, melting point, and boiling point.

Viscosity – The tendency of a liquid to keep from flowing.

viscosity
The Greater the Viscosity =

the S L O W E R the liquid moves.

Viscosity usually decreases when the liquid is ______________.

Viscosity

heated

conductivity
Which spoon would you leave in a pot of boiling water?

Wooden or Metal ?

Conductivity

A material’s ability to allow heat (or electricity) to flow is known as Conductivity.

malleability
The ancient gold objects found in tombs in Greece were made by tapping GOLD with a hammer and punch. Gold can be shaped because it is malleable.

Malleability - is the ability of a solid to be hammered without shattering.

Most metals are malleable.

Malleability
slide46

Properties of Matter

15.2

Appearance

  • How would you describe a tennis ball? You could begin by describing its shape, color, and state of matter.
  • You can measure some physical properties, too. For instance, you could measure the diameter of the ball.
slide47

Properties of Matter

15.2

Behavior

  • Some physical properties describe the behavior of a material or a substance.
  • Attraction to a magnet is a physical property of the substance iron.
  • Every substance has a specific combination of physical properties that make it useful for certain tasks.
slide48

Properties of Matter

15.2

Using Physical Properties to Separate

  • The best way to separate substances depends on their physical properties.
  • Size is one physical property often used to separate substances.
slide49

Properties of Matter

15.2

Using Physical Properties to Separate

  • Look at the mixture of iron filings and sand shown.
  • You probably won’t be able to sift out the iron filings because they are similar in size to the sand particles. What you can do is pass a magnet through the mixture.
slide50

Properties of Matter

15.2

Using Physical Properties to Separate

  • The magnet attracts only the iron filings and pulls them from the sand. This is an example of how a physical property, such as magnetic attraction, can be used to separate substances in a mixture.
slide51

Properties of Matter

15.2

Physical Change

The Identity Remains the Same

  • A change in size, shape, or state of matter is called a physical change.
  • These changes might involve energy changes, but the kind of substance—the identity of the element or compound—does not change.
slide52

Properties of Matter

15.2

The Identity Remains the Same

  • Iron is a substance that can change states if it absorbs or releases enough energy—at high temperatures, it melts.
  • Color changes can accompany a physical change, too.
slide53

Properties of Matter

15.2

The Identity Remains the Same

  • For example, when iron is heated it first glows red. Then, if it is heated to a higher temperature, it turns white.
slide54

Properties of Matter

15.2

Using Physical Change to Separate

  • Many such areas that lie close to the sea obtain drinking water by using physical properties of water to separate it from the salt.
  • One of these methods, which uses the property of boiling point, is a type of distillation.
slide55

Properties of Matter

15.2

Distillation

  • The process for separating substances in a mixture by evaporating a liquid and recondensing its vapor is distillation.
  • It usually is done in the laboratory using an apparatus similar to that shown.
slide56

Properties of Matter

15.2

Distillation

  • Two liquids having different boiling points can be separated in a similar way.
  • The mixture is heated slowly until it begins to boil.
  • Vapors of the liquid with the lowest boiling point form first and are condensed and collected. Then, the temperature is increased until the second liquid boils, condenses, and is collected.
slide59

Properties of Matter

15.2

Chemical Properties and Changes

  • The tendency of a substance toburn, or its flammability, is an example of a chemical property because burning produces new substances during a chemical change.
  • A chemical property is a characteristic of a substance that indicates whether it can undergo a certain chemical change.
reactivity
Reactivity – the property that describes how readily a substance combines chemically with another substance.

Nitrogen – Low reactivity

Oxygen – Very high reactivity

Ox. Reacts with most other elements.

Ex. O reacts with iron and water to form

______________.

Reactivity

Rust

how you recognize a chemical change
3 common types of Evidence for a Chemical Change.

A. Change in Color

Ex: Gold, Brass, and Silver tarnish

B. Production of a gas

Ex: Baking Soda and Vinegar

C. Formation of a precipitate

If you add lemon juice or vinegar to milk, small bits of white solid will separate from the liquid.

Its called Milk Curdling

How You recognize a Chemical Change
slide63

Properties of Matter

15.2

Detecting Chemical Change

  • If you leave a pan of chili cooking unattended on the stove for too long, your nose soon tells you that something is wrong.
  • This burnt odor is a clue telling you that a new substance has formed.
slide64

Properties of Matter

15.2

The Identity Changes

  • A change of one substance to another is a chemical change.
  • The foaming of an antacid tablet in a glass of water and the smell in the air after a thunderstorm are other signs of new substances being produced.

Click image to view movie

slide65

Properties of Matter

15.2

The Identity Changes

  • Clues such as heat, cooling, or the formation of bubbles or solids in a liquid are helpful indicators that a reaction is taking place.
  • However, the only sure proof is that a new substance is produced.
  • The only clue that iron has changed into a new substance is the presence of rust.
  • Burning and rusting are chemical changes because new substances form.
slide66

Properties of Matter

15.2

Using Chemical Change to Separate

  • One case where you might separate substances using a chemical change is in cleaning tarnished silver.
  • Tarnish is a chemical reaction between silver metal and sulfur compounds in the air which results in silver sulfide.
  • It can be changed back into silver using a chemical reaction.
slide67

Properties of Matter

15.2

Using Chemical Change to Separate

  • You don’t usually separate substances using chemical changes in the home.
  • In industry and chemical laboratories, however, this kind of separation is common. For example, many metals are separated from their ores and then purified using chemical changes.
slide68

Properties of Matter

15.2

Weathering—Chemical or Physical Change?

  • The forces of nature continuously shape Earth’s surface. Rocks split, deep canyons are carved out, sand dunes shift, and curious limestone formations decorate caves.
  • Do you think these changes, often referred to as weathering, are physical or chemical?
  • The answer is both.
slide69

Properties of Matter

15.2

Physical

  • Large rocks can split when water seeps into small cracks, freezes, and expands.
  • However, the smaller pieces of newly exposed rock still have the same properties as the original sample.
  • This is a physical change.
slide70

Properties of Matter

15.2

Chemical

  • A chemical change produces caves and the icicle shaped rock formations that often are found in them.
  • Limestone dissolves in slightly acidic moisture that seeps through the ground
slide71

Properties of Matter

15.2

The Conservation of Mass

  • Suppose you burn a large log until nothing is left but a small pile of ashes.
  • At first, you might think that matter was lost during this change because the pile of ashes looks much smaller than the log did.
slide72

Properties of Matter

15.2

The Conservation of Mass

  • In fact, the mass of the ashes is less than that of the log.
slide73

Properties of Matter

15.2

The Conservation of Mass

  • However, suppose that you could collect all the oxygen in the air that was combined with the log during the burning and all the smoke and gases that escaped from the burning log and measure their masses, too.
  • Then you would find that no mass was lost after all.
slide74

Properties of Matter

15.2

The Conservation of Mass

  • Not only is NO mass lost during burning, mass is not gained or lost during any chemical change.
  • According to the law of conservation of mass, the mass of all substances that are present before a chemical change equals the mass of all the substances that remain after the change.
slide75

Section Check

15.2

Question 1

Which of the following is a chemical property?

A. boiling point

B. density

C. flammability

D. melting point

slide76

Section Check

15.2

Answer

The answer is C. Flammability indicates whether a substance will undergo the chemical change of burning.

slide77

Section Check

15.2

Question 2

A characteristic of a material that can be observed without changing the identity of the substances that make up the material is a _______.

slide78

Section Check

15.2

Answer

The answer is physical property. Examples of physical properties include color, shape, and density.

slide79

Section Check

15.2

Question 3

What is the law of conservation of mass?

slide80

Section Check

15.2

Answer

According to the law of conservation of mass, the mass of all substances that are present before a chemical change equals the mass of all substances that remain after the change.

mixture stuff lab activity
This activity will have you, the students, determine if some “stuff” is a(n) element, compound, or mixture. You will develop and write your own procedure and then write a conclusion based on your data.

Acceptable Materials:

Ring, Ring Stand, Filter Paper, Funnel, Magnet, Cups, Graduated Cylinder, Water, Beakers, Watch Glass, and Glass Stirring Rod

Mixture: Stuff Lab Activity