Table of Contents

Chapter: Matter and Its Changes

Section 1: Physical Properties and Changes

Physical properties of an

object

color, shape Length, mass, volume, density State of matter – solid, liquid, gas

Melting and Boiling Points

Metallic properties magnetic, malleability, and ductility

1 Physical Properties and Changes

Using Your Senses

• Observing involves seeing, hearing, tasting, touching, and smelling.

• Any characteristic of a material that can be observed or measured without changing the identity of the material is a

physical property

.

1 Physical Properties and Changes

Physical Properties— Color and Shape

• The detergent bottles shown are made plastic regardless of the differences in the physical properties of color or shape.

Physical Properties and Changes 1

Length and Mass

• One useful and measurable physical property is length. • Length is measured using a ruler, meterstick, or tape measure. • Objects can be classified by their length.

1 Physical Properties and Changes

Length and Mass

• Mass is a physical property that describes the amount of material in an object. • For example, two boxes of the

same

detergent may have different masses. One box may be heavier than the other but the

formula

detergent in each box is the same.

of the

1 Physical Properties and Changes

Volume and Density

• Volume measures the amount of space an object takes up. • Liquids usually are measured by volume.

1 Physical Properties and Changes

Physical Properties— Color and Shape

•

Matter

is anything that has mass and takes up space. In a

physical change

, the physical properties a substance change, but not what it is (the identity) of A piece of clay weather red or blue is still clay

1 Physical Properties and Changes

Volume and Density

• Another measurable physical property related to mass and volume is

density

—the amount of mass a material has in a given volume. • Density is found by dividing the mass of an object by its volume. • density = mass/volume, or

D = m

/

V

Physical Properties and Changes 1

Same Volume, Different Mass

• These balls take up about the same space, but the bowling ball has more mass than the other ball. • Therefore, the bowling ball is more dense.

Related to state of matter of a material energy gas liquid Density solid

Heat = energy Things need more space as they get more energy

Does a substance have more space between its molecules because it has more energy Or does it have more energy because it has more space between its molecules

1 Physical Properties and Changes

Same Volume, Different Mass

•

The density of a material stays the same as long as pressure and temperature stay the same.

• Water at room temperature has a density of 1.00 g/cm 3 . When you do change the

temperature

or

pressure

material

can change

. , the

density

of a

Physical Properties and Changes 1

States of Matter

• The four

states of matter

are solid, liquid, gas and plasma (PLAZ muh).

• The

state of matter of a substance

depends on its temperature and pressure

.

Click image to view movie.

1 Physical Properties and Changes

States of Matter

• The state of matter of a material is a physical property .

Physical Properties and Changes 1

States of Matter

• The

plasma state

occurs at

very high temperatures

and is found in fluorescent (floo RE sunt) lightbulbs, the atmosphere , and in lightning strikes . •

The state of matter of a material is another physical property.

Objective: Chemical Reactions

Objective: Understanding States of Matter

Physical Properties and Changes

The material stays the same

1. color and shape a. making a ball of clay into a cube of clay b. Painting a chair red

Physical Properties and Changes

The material stays the same

1. color and shape a. making a ball of clay into a log of clay b. Painting a chair red 2. Length and mass a. if cut or decreased in size – only a physical change still is the same material cutting a carrot ino smaller chunks

Physical Properties and Changes

The material stays the same

1. color and shape a. making a ball of clay into a log of clay b. Painting a chair red 2. Length and mass a. if cut or decreased in size – only a physical change still is the same material cutting a carrot ino smaller chunks 3. Density – a physical quality involving mass and volume is a characteristic to identify a material

A material’s density can change by changing room temp or pressure but it remains the same material

States of Matter Energy Levels

Energy Level Increasing

Highest Gas Middle Liquid Lowest Solid Increasing heat will cause lead to increased kinetic energy.

Increasing heat causes decreased density, increases volume but keeping the amount of mass the same.

Higher energy causes greater motion of the molecules and so they spread apart

Physical properties of States of Matter Definite volume Definite shape of container Solid Yes Yes

Physical properties of States of Matter Definite volume Definite shape of container Solid Yes Yes Liquid Yes No

Physical Properties of States of Matter Definite volume Definite shape of container Solid Yes Yes Liquid Gas Yes No – will take volume of container it is in No no

Melting and Boiling Points Melting point – a solid becomes a liquid Boiling point – a liquid becomes a gas Melting and boiling points are physical properties used to identify (classify) materials Every pure material has a boiling and melting point of its own

Material

water nitrogen Lead

Melt

32 F ( 0 C) 327.5 C

Boil

212 F (100 C) -195.8 C

Properties of Metals Luster

- the shiny nature of the material Such as a new penny or coin

Malleability

– to be shaped by hammering Shaping a sword by hammering on an anvil

Ductility

– ability to be pulled into a wire

Magnetic

– ability to be attracted to a magnet

Physical Properties and Changes 1

Moving Particles

•

Matter

is made up of

moving particles.

• The particles of a solid vibrate in a fixed position. • They remain

close together

and give the

solid a definite shape and volume

.

Physical Properties and Changes 1

Moving Particles

• The particles of a

liquid moving much faster

are and have

enough energy to slide past on another

. • This allows a

liquid

to take the

shape of its container

.

Physical Properties and Changes 1

Moving Particles

•

Gas particles

of a are

moving so quickly

that they have enough

energy

to

move freely away from other

particles and

will spread out to fill any container

.

Which direction, why?

cold air Hot air

1 Physical Properties and Changes

Changes of State

• You witness a change of state when you place ice cubes in a cup and they melt. • You still have water but in another form. • The opposite physical change happens when you put liquid water in ice-cube trays and pop them in your freezer.

1 Physical Properties and Changes

Melting and Boiling Points

• The temperature liquid is its at which a

melting point

. solid becomes a • The melting point of a pure substance does not change with the amount of the substance.

Physical Properties and Changes 1

Melting and Boiling Points

• When a substance melts, it changes from a solid to a liquid.

• This is a physical change, and the melting point is a physical property.

1 Physical Properties and Changes

Melting and Boiling Points

• The

boiling point

is the

temperature

at which a liquid becomes a gas.

1 Physical Properties and Changes

Melting and Boiling Points

• Each pure substance has a unique boiling point.

•

The boiling point of water is 100°C

1 Physical Properties and Changes

Melting and Boiling Points

• The boiling and melting point can help to identify a substance . • If you know the boiling points and melting points of substances, you can classify substances based on those properties.

“ A ” “B” “ A1 heated ” Same mass “B” Room temp “ A2 ” heated more Same mass “B” Room temp Same mass

A A A 1 A 2 If their state of matter

wasn’t

changed, what happened?

A A A 1 A 2 If their state of matter

was

changed, name them

As you heat a material and compare it to the same unheated material the density of the heated material will decrease as the molecules spread and the volume increases.

1 Physical Properties and Changes

Metallic Properties

You can classify things as solids, liquids or gases or according to color, shape, length, mass, volume or density.

What properties do metals have?

Physical Properties and Changes 1

How do metals look?

• Metals - a shiny appearance. • This shine is called luster . • Words to describe the appearance of nonmetallic objects are

pearly, milky,

or

dull

.

1 Physical Properties and Changes

Uses of Metals

• This property of metals is called malleability • Many metals can be hammered, pressed or rolled into thin sheets.

1 Physical Properties and Changes

Uses of Metals

• Many metals can be drawn into wires = ductility

1 Physical Properties and Changes

Uses of Metals

• Some metals respond to magnets. • Some metals have groups of atoms that can be affected by the force of a magnet, and they are attracted to the magnet because of that force.

1 Physical Properties and Changes

Using Physical Properties

• Physical properties—such as appearance, state, shape, length, mass, volume, ability to attract a magnet, density, melting point, boiling point, malleability, and ductility can be used to help you identify, separate, and classify substances.

1 Physical Properties and Changes

Sorting and Separating

• When you do laundry, you sort according to physical properties. Perhaps you sort by color. What are some things you may sort?

Think of trick or treat

Physical Properties and Changes 1

Sorting and Separating

• Scientists who work with animals use physical properties or characteristics to determine the identity of a specimen. • They do this by using a tool called a dichotomous key.

Physical Properties and Changes 1

Sorting and Separating

• To begin the identification of you unknown animal, you are given two choices . • Your animal will match only one of the choices. • Based on your answer, you are either directed to another set of choices or given the name of the specimen you are identifying.

1 Physical Properties and Changes

Sorting and Separating

All things yes yes Human, mouse, grasshopper, etc Is it alive Can it talk no no Car, button, chalk

1 Physical Properties and Changes

Sorting and Separating

All things yes yes Human, mouse, grasshopper, etc Is it alive Can it talk no no Car, button, chalk

1 Physical Properties and Changes

Narrowing the Options

• Often, determining the identity of something that is unknown is easiest by using the process of elimination. • Scientists use similar methods to determine the identities of living and nonliving things.

Label and describe the energy of the particles In each state of matter

Table of Contents

Chapter: Matter and Its Changes

Section 2: Chemical Properties and Changes

Chemical properties: 1. Ability to burn wood catches fire 1. React with oxygen or sulfur iron forms rust, silver tarnishes 2. React with heat or light fading of ink, fabric 3. Break down by electricity water becomes hydrogen and oxygen

Signs of chemical change: 1. new material formed 2. bubbles 3. production of heat, light, smoke 4. change in color such as fading 5. production of sound

Chemical property

The ability to do something flammability React with oxygen React with light React to electric current

Chemical change

What happened Word burned Nail rusted Curtain faded Water breaks down to oxygen and hydrogen

Watch the demo in the bottle Draw and label picture 1. before 2. after (during) What do you see?

What is this a sign of?

Examine the brush (car) What do you notice?

Name the product?

How did it happen?

What is the property?

What kind of change is this?

Chemical Properties and Changes 1. Flammability (burns) producing new materials 2. Reacts with other chemicals producing new materials 3. Changes when exposed to heat or light producing new materials 4. Changes when electricity goes thru it producing new materials

Chemical Properties and Changes

Signs of a Chemical Change

•

Bubbles

are a sign that a chemical change has taken place.

• Other signs of a chemical change include: the production of:

a new material (a solid (powder), liquid, or gas)

, ,

smoke, light

,

heat , change in color , or sound.

Chemical Properties and Changes 2

Ability to Change

• Some properties do indicate a change of identity for the substances involved. • A

chemical property

is a characteristic that gives a substance the ability to undergo a change . (Flammability is a chemical property) • It results in a new substance.

2 Chemical Properties and Changes

Common Chemical Properties

• A

chemical change

is a change in the identity of a substance. A change has occurred in the chemical properties of that substance. (paper burns to ashes – it is no longer paper, its properties have changed) • A new substance or substances are formed as a result of such a change.

Chemical Properties and Changes

The Law of Conservation of Mass

• The

law of conservation of mass

states that the mass of what you end with is always the same as the mass of what you start with. Mass is not created or destroyed When something is burned the ashes remain but the rest of the mass is changed to gases and smoke Oxygen + Log

= MASS before =

other gases + ashes + smoke

MASS after

Chemical Properties and Changes 2

Classify According to Chemical Properties

• Physical properties of a substance are easily observed, but the chemical properties can’t be observed without changing the substance.

Chemical Properties and Changes

Classifying by to Chemical Properties

Properties

2 Chemical Properties and Changes

Ability to Change

•

Chemical property

a characteristic that gives a substance the ability to change and

results in a new substance .

2 Chemical Properties and Changes

Common Chemical Properties

• A

chemical change

is a

change in the identity

substance because of the due to the chemical properties of the new substance. of a •

It causes a new substance or substances to form

a result of the change. as •Burn wood you get charcoal •Expose an apple or banana to air the dark material is a new substance

2 Chemical Properties and Changes

Common Chemical Properties

• Wood can burn.

• This chemical property is called flammability . What results from burning wood?

2 Chemical Properties and Changes

Common Chemical Properties

1.

Flammability – the ability to burn.

2.

Reacting with other chemicals a. iron reacts with oxygen – rust forms (corrosion) iron oxide b. copper reacts with oxygen turn green c. silver turns black – it reacts sulfur in air or sweat

Chemical Properties and Changes 2

Common Reactions

• An unpainted iron gate will rust in time. • The rust is a result of oxygen reacting with the iron in the air and causing corrosion. • rust is a new substance called iron oxide,

Chemical Properties and Changes 2

Common Reactions

• Tarnish develops on silver with sulfur in the air. when it reacts • The ability to react with different chemicals is a chemical property . Iron – to oxygen Copper – to oxygen Silver – to sulfur

Chemical Properties and Changes 2

Heat and Light

• Many vitamins will change when exposed to light, curtains when exposed to the sun • This is a chemical property.

• They are protected in colored bottles from undergoing a chemical change with light.

Chemical Properties and Changes 2

Heat and Light

• Some substances are sensitive to heat or cooling. They will undergo a chemical change only when heated or cooled. • One example is limestone. If limestone is heated , it goes through a chemical change and produces carbon dioxide and lime.

2 Chemical Properties and Changes

Heat and Light

• Another chemical property is the ability to change with electrical contact.

• Electricity can cause a change in some substances and decompose (break down) some compounds. • Water is one compound that can be broken down with electricity. It forms hydrogen and oxygen

Chemical Properties and Changes

4. Change when electricity is put thru it

• Ability to change with electrical contact. • Electricity can cause a change in some substances and decompose ( break down to components it is made of) some compounds. • Water is one compound that can be broken down with electricity.

Chemical Properties and Changes 2

Something New

• The important differences in a chemical change in that a new substance is formed . • If eggs, sugar, flour, and other ingredients didn’t change chemically through baking, you couldn’t enjoy birthday cake. • Cake begins as liquid and ends as solid. The baked cake clearly has different physical and chemical properties.

Chemical Properties and Changes 2

Signs of Change

• Bubbles are a sign that a chemical change has taken place. • Other signs of a chemical change

include: the

production of heat , light, smoke , change in color, and sound .

2 Chemical Properties and Changes

Is it reversible?

• Chemical changes can’t be reversed using physical means . • For example, the ashes in a fireplace cannot be put back together to make the logs that you had to start with.

Chemical Properties and Changes 2

Classify According to Chemical Properties

• The physical properties of a substance are easily observed, but the chemical properties can’t be observed without changing the substance.

Chemical Properties and Changes 2

Classify According to Chemical Properties

• However, once you know the chemical properties, you can classify and identify matter based on those properties.

Chemical Properties and Changes 2

Classify According to Chemical Properties

• For example, if you try to burn what looks like a piece of wood but find that it won’t burn, you can rule out that it is wood All matter Can it burn May be wood Not wood

Chemical Properties and Changes 2

The Law of Conservation of Mass

• The

law of conservation of mass

states that the mass of what you end with is always the same as the mass of what you start with. • He determined that a fire does not make mass disappear or truly get rid of anything.

Chemical Properties and Changes 2

Where did the mass go?

• When flammable materials burn, they combine with oxygen. Ash, smoke, and gases are produced. • The smoke and gases escape into the air.

2 Chemical Properties and Changes

Where did the mass go?

• If you could measure the mass of the oxygen and all of the original firewood that was burned and compare it to the remaining mass of the ash, smoke, and gas, they would be equal. • Mass is not destroyed or created during any chemical change.