Properties and Classification of MatterHow can we describe and identify matter?

What is matter?•Anything that has mass and takes up

space is called matter•In chemistry, we study what matter looks

like, the composition of matter, and how matter changes.

Properties of MatterWhat does matter “look like?”

What is a property?•A property is something that describes

what the substance looks like, or how it behaves

•Chemists observe the substance and identify all the unique characteristics.

•Chemists can then use those properties to identify a sample of unknown matter.

Properties can be physical or chemicalPhysical Properties Chemical Properties• How a substance “looks”• Can observe without

changing the identity of the substance

• Example- Silver is lustrous, or shiny. ▫ In order to determine

that silver is shiny, did you have to make the chemical change into something else?

• How a substance behaves• Have to change the

identity of the substance• Example- Alcohol is very

flammable▫ How can you determine

if something catches fire easily?

▫ What happens to that substance when it does catch fire?

More examples of Physical properties• Color, odor, texture, density, magnetic, conductivity• Lustrous – how shiny a metal is• Ductile – how easily a metal is hammered• Malleability – how easily a metal is bent

▫Aluminum has a high malleability• Hardness – the ability to scratch another substance

and/or be scratched by another substance▫A diamond is the hardest substance – can scratch

any other substance, cannot be scratched by anything except another diamond

Physical properties that require a physical change•Melting point•Freezing point•Boiling point•Ability to dissolve

▫All of these changes will NOT CHANGE the identity of the substance

▫If ice melts into liquid water, is it still H2O?

Examples of Chemical properties•Flammability – how easily a substance

catches on fire•Reactivity – how easily a substance

reacts to form a new substance▫A substance that does not easily react is

also said to be STABLE•Volatility – how easily a liquid becomes a

vapor

Examples of Chemical Properties•Stability/reactivity•Toxicity•pH•Fermentation•Oxidation•Flammability

DANGER!!!!!!• Hazardous: material that can burn,

explode, damage skin, or poison someone.

• Highly Reactive: always use safety goggles

• High Corrosive: able to burn organic material▫Examples of corrosive materials:

acids and bases

Properties can also be intensive or extensiveIntensive Properties Extensive Properties• Think interior, its what’s

on the inside that counts • Does not depend on the

amount that you have• Example: Density

▫ The density of gold will always be 19.3 g /mL. It does not matter if you have a tiny gold coin, or a huge block of gold

• Think exterior, its all about appearances…

• DOES depend of the amount you have

• Example: Mass▫ If I have 2 blocks of

gold, and you have 10 blocks of gold, is that different?

QUICK WRITE!You hear that gold has been found in California! You rush there to try and get rich. You are searching, and you think you have found a sample of pure gold! Describe what you can do to prove that the gold you have found is not fake.

You must use the 9 of the following 14 words:property chemical physical intensiveextensive density malleabilitylustrous dissolve melting boiling

matter conductivity magnetic

Physical Changes A change that alters the

physical properties of a substance but does not change its identity

Physical changes do not form new substances! EX:

sugar dissolving Cutting of paper (change in shape or

size) Phase changes (solid-liquid-gas)

Physical changes are easy to undo (with some exceptions!)

Chemical Changes• A process involving one or more

substances changing into new substances

• You can observe chemical properties only when a chemical change occurs!

• New substances with different properties are formed

• Examples:– baking a cake– iron reacting with oxygen to form rust

Evidence of Chemical Change•Gas/Vapor produced•Color change•Temperature change•Burning•Tarnish/rust•Precipitate (a solid) is produced•New odor•Light is produced•Bubbles

Classification of matterWhat do we call it?

How can we put matter into groups?•Chemists use the following to group

matter into categories▫How simple it is▫If and/or how it can be separated▫How it is combined with other substances

Pure Substances: Elements•Simplest form of matter•Cannot be separated by

any means•Not combined with any

other elements•Can find on the periodic

table•Examples: Gold (Au),

Iron (Fe), Oxygen (O2)▫Look for 1 capital letter!

Pure Substances: Compounds• Two or more elements

chemically combined• Can be separated by chemical

means (like a chemical reaction)Cannot be separated by physical means

• Examples: Water (H2O), Carbon dioxide (CO2), Chalk or Calcium carbonate (CaCO3)▫Look for more than 1 capital

letter!

Mixtures•Two or more pure

substances mixed together•Can be separated by

physical means, such as filtration, or heating

•Examples: Soup▫How can you physically

separate the parts of soup?

•Can be Homogeneous or Heterogeneous

HETEROGENEOUS MIXTURE ELEMENT

yesno

Examples: granite rock, beach sand, cereal,

Matter

Can it be separated by physical means? Is it composed of the same stuff?

yes no

MIXTURE PURE SUBSTANCE

Is the composition variable? Can you see chunks of different things?

Can it be separated by chemical means? Does it contain more than one chemical element? Does the chemical formula have more than one capital letter?

HOMOGENEOUS MIXTURE COMPOUND

yesno

Examples: air, sugar water, stainless steel, salt water

Examples: water, salt, quartz, glucose

Examples: oxygen, gold, aluminum, iron

Let’s Practice!Is it an :

ELEMENTCOMPOUNDMIXTURE

MercuryElement!

Table salt, or sodium chloride (NaCl)Compound!

CoffeeHomogeneous Mixture

SoilHeterogeneous Mixture

IronElement

ConcreteHeterogeneous Mixture

States of Matter Notes

The Three States of Matter•Solid

•Liquid

•Gas

Basis of Classification of the Four Types

The Classification and Properties of Matter Depend Upon Microscopic

Structure

Particle arrangementParticle kinetic energyParticle to particle distance

•The state of matter can be altered by:• adding or removing energy (AKA heat)

and/or pressure •This can affect the arrangement and

energy of the particles.

Solids Shape:

Have a definite shape Volume:

Have a definite volume. KE:

Particles of solids are tightly packed, vibrating about a fixed position therefore they have the lowest kinetic energy of the three states

Compressibility: Solids are not easily compressible and are not fluid

because there is little free space between particles.

• Solids

Particle Movement Examples

Liquids Shape:

indefinite shape because the particles can slide past one another

Volume: definite volume

KE: More kinetic energy than a solid because particles of

liquids are tightly packed, but are far enough apart to slide over one another.

Compressibility: not easily compressible because there is little free space

between particles. (more compressible than a solid) Liquids are fluid because the particles can move/slide past

one another.

• LiquidsParticle Movement Examples

Gases Shape:

indefinite shape because particles can move past one another. Volume:

indefinite volume because the particles can move past one another.

KE: Gases have high kinetic energy (molecules move the fastest of

the three) because particles of gases are very far apart and therefore move randomly.

Compressibility: Gases are easily compressible because there is a great deal of

free space between particles. Gases are fluid because the particles randomly move past one

another.

GasesParticle Movement Examples

ComparisonThe Classification and Properties of Matter

Depend Upon Microscopic Structure

Particle arrangementParticle kinetic energyParticle to particle distance

Heating Curve of Water

??????????•When a substance changes from a solid to

a liquid, what normally happens to its density?

•Why? (Think of the density formula.)

•Why does water not follow that general rule?