Matter: anything that has mass and Matter: anything that has mass and takes up spacetakes up space Mass – the amount of matter in somethingMass – the amount of matter in something Volume – the amount of space something Volume – the amount of space something

occupiesoccupies

Which of the following is matter?Which of the following is matter? A car?A car? A box?A box? You?You?

Reviewing MATTERReviewing MATTER

What is a property?What is a property?

PropertyProperty: a : a characteristic characteristic of a substance of a substance that can be that can be observedobserved

Physical Property Physical Property

Physical property: a property that can be observed without changing the identity of the substance.

Examples:

• luster

• malleability: the ability to be hammered into a thin sheet

• ductility: the ability to be stretched into a wire

• melting point

• boiling point

• density

• solubility

• specific heat

EXTENSIVE PROPERTYEXTENSIVE PROPERTY Depends on the Depends on the amountamount of matter. of matter.

Example – Example – Length, mass,Length, mass,

volume, weightvolume, weight

Additional Physical Additional Physical Properties…Properties…

INTENSIVE PROPERTYINTENSIVE PROPERTY

Does Does notnot depend on the amount of depend on the amount of matter.matter.

Example – Color, density, Example – Color, density, hardness, ductility, hardness, ductility,

malleability, odor, malleability, odor,

melting/ boiling pointmelting/ boiling point

Special Physical Special Physical PropertiesProperties

Melting pointMelting point: the : the temperature at which a temperature at which a substance changes from a substance changes from a solid to a liquid at a given solid to a liquid at a given pressure pressure

water = 0water = 0ooCC

Special Physical Special Physical PropertiesProperties

Boiling pointBoiling point: the : the temperature at which a temperature at which a substance changes from a substance changes from a liquid to a gas at a given liquid to a gas at a given pressurepressure

water = 100water = 100ooCC

DensityDensity DensityDensity is the amount of mass per is the amount of mass per

unit of volume.unit of volume. Since density is an Since density is an intensiveintensive

property, it can be used to identify property, it can be used to identify a substance.a substance.

Density Density

The density of water is The density of water is 1.0g/mL1.0g/mL

If a substance has a density If a substance has a density higherhigher than 1 it will than 1 it will sinksink in in water, water, lessless than 1 it will than 1 it will floatfloat in water.in water.

Density CalculationsDensity Calculations

Calculations:Calculations:

Density = Density = mass mass = = g/mL = g/cm3

VolumeVolume

Units are grams/ml or grams/cm3Units are grams/ml or grams/cm3

where mass is measured in grams and where mass is measured in grams and

volume is measured in ml or cm3volume is measured in ml or cm3

Density CalculationsDensity Calculations

A cube has a mass of 2.8 g and occupies a A cube has a mass of 2.8 g and occupies a volume of 3.67 ml. Would this object float or volume of 3.67 ml. Would this object float or sink in water?sink in water?

Mass = 2.8 gMass = 2.8 g Volume = 3.67 mLVolume = 3.67 mL

D = 2.8g/3.67 mL= 0.76 g/mLD = 2.8g/3.67 mL= 0.76 g/mL

This object would float in water because its This object would float in water because its density is less than water (1.0 g/mL).density is less than water (1.0 g/mL).

Chemical PropertiesChemical Properties Chemical propertyChemical property: a property that : a property that

can only be observed by changing can only be observed by changing the identity of the substancethe identity of the substance

Examples:

•Flammability: ability to burn

•Ability to rust

•reactivity with vinegar

PHYSICAL & CHEMICAL PHYSICAL & CHEMICAL CHANGESCHANGES

Changes in matterChanges in matter

Change: the act of altering a Change: the act of altering a substancesubstance

In science, we talk of two types In science, we talk of two types of changes:of changes:

physicalphysical

chemicalchemical

Physical ChangePhysical Change

Physical change: a change that occurs Physical change: a change that occurs that does not change the identity or that does not change the identity or make up of the substancemake up of the substance Melting ice (change in state or phase)Melting ice (change in state or phase) Freezing Kool-aidFreezing Kool-aid Tearing paperTearing paper Boiling water (same as melting)Boiling water (same as melting)

Physical ChangesPhysical Changes

Physical changes Physical changes are changes that are changes that alter the size, alter the size, shape, location or shape, location or physical state of a physical state of a substance but not substance but not its its chemicalchemical state. state.

Here’s An Example…Here’s An Example… A physical change in a substance doesn't A physical change in a substance doesn't

change what the change what the substance is.substance is. cutting paper – cutting paper –

physical change in the shape and size physical change in the shape and size of the paper. of the paper.

It is still It is still paper!!!!!!paper!!!!!!

So What Does That All Mean?So What Does That All Mean? If the substance is still the same If the substance is still the same

substancesubstance after it has been after it has been changed…changed… It’s a Physical Change.It’s a Physical Change. Example… Boiling waterExample… Boiling water Boiling Water becomes Boiling Water becomes

Water vapor Water vapor

Water = waterWater = water

What Other Kinds of What Other Kinds of Changes Are Physical?Changes Are Physical?

CuttingCutting TearingTearing ShreddingShredding ShrinkingShrinking EnlargingEnlarging

Change in Change in Phase Phase

RelocatingRelocating DissolvingDissolving RotatingRotating Molding Molding

(shaping)(shaping)

Under certain conditions, a substance can change from any one state of matter another. Changes of state are physical changes.

Wood cut down into logs is a physical change

Chemical ChangesChemical Changes

Chemical change: a change that Chemical change: a change that occurs causing the identity of the occurs causing the identity of the substance to changesubstance to change BurningBurning Digesting food Digesting food Reacting with other substancesReacting with other substances

A chemical change is also called a A chemical change is also called a chemical reactionchemical reaction

Chemical ChangesChemical Changes

Chemical changes Chemical changes are changes that are changes that alter the alter the chemical chemical make up of the make up of the substance being substance being changed.changed.

Chemical ChangesChemical Changes

If you end up with a chemical If you end up with a chemical or chemicals that you did not or chemicals that you did not start with. . . start with. . .

It is a chemical change!!!!!!!It is a chemical change!!!!!!!

Chemical ChangesChemical Changes A new substance is formed A new substance is formed

with new and different with new and different properties.properties.

A chemical change is not A chemical change is not easily reversed. easily reversed.

Signs That a Chemical Signs That a Chemical Change has occurredChange has occurred

Creation of a gas (bubbles)Creation of a gas (bubbles) Creation or loss of heatCreation or loss of heat FireFire RottingRotting Breaking down (decomposition)Breaking down (decomposition) Precipitation (Sour milk clumps)Precipitation (Sour milk clumps) CookingCooking Rusting (oxidation)Rusting (oxidation)

The strike of a match is a chemical change due to the reaction of the chemicals with oxygen.

Burning woods turns to charcoal and ashes. This is a chemical change.

Is it Physical or Is it Physical or Chemical?Chemical?

ChangeChange PhysicalPhysical ChemicalChemical

Melting cheeseMelting cheese

Burning woodBurning wood

Milk souringMilk souring

Folding up paperFolding up paper

Bicycle rustingBicycle rusting

Start physical changes challenge PowerpointStart physical changes challenge Powerpoint

Chemical Reactions are…Chemical Reactions are… When one or more substances are changed When one or more substances are changed

into new substances.into new substances. ReactantsReactants- the stuff you start with- the stuff you start with ProductsProducts- what you make- what you make The products will have NEW The products will have NEW

PROPERTIES different from the reactants PROPERTIES different from the reactants you started withyou started with

Arrow points from the reactants Arrow points from the reactants toto the the new productsnew products

Plants make chlorophyll in the plants leaves.

The color changes in autumn leaves are due, in part, to the ending of a chemical reaction. The plants stop making chlorophyll while existing chlorophyll is breaking down. The brilliant colors of fall foliage result when green chlorophyll in leaves breaks down. The colors of other substances in the leaves become visible.

The copper-covered Statue of Liberty has stood in upper New York Bay for more than a 100 years. The green color of the Statue of Liberty comes from a change to the statues copper metal covering. These changes are a result from chemical reactions.

Conservation of Mass Conservation of Mass During any chemical reaction, the mass of During any chemical reaction, the mass of

the products is always equal to the mass the products is always equal to the mass of the reactants.of the reactants.

All the massAll the mass can be accounted for: can be accounted for: Burning of wood results in products that Burning of wood results in products that

appear to have less mass as ashes; where is appear to have less mass as ashes; where is the rest?the rest?

Law of conservation of massLaw of conservation of mass

Matter changes whenever energy is added or taken away. In every physical and chemical change, the total amount of energy stays the same. This principle is called the Law of Conservation of Energy.