Matter & Its PropertiesCh 1: Lesson 3 Honors Chemistry K. Davis

Matter

Matter – anything that has mass and takes up spaceEverything around us

Chemistry – the study of matter and the changes it undergoes

SubstancesAtoms: the building blocks of all

matter Ions: atoms that become negatively

or positively charged Element: matter containing only one

type of atom; ex. hydrogen and oxygen

Four States of Matter

Solidsparticles vibrate but can’t move

aroundfixed shape fixed volumeincompressible

Four States of Matter

Liquidsparticles can move

around but are still close together

variable shapefixed volumeVirtually incompressible

Four States of MatterGases

particles can separate and move throughout container

variable shapevariable volumeEasily compressedVapor = gaseous state of a

substance that is a liquid or solid at room temperature

Four States of Matter

Plasmaparticles collide with enough energy

to break into charged particles (+/-)gas-like, variable

shape & volumestars, fluorescent

light bulbs, TV tubes

Four States of Matter

Physical PropertiesPhysical Property

can be observed without changing the identity of the substance

Physical PropertiesPhysical properties can be described

as one of 2 types:

Extensive Propertydepends on the amount of matter

present (example: length) Intensive Property

depends on the identity of substance, not the amount (example: scent)

Intensive Physical PropertiesThe intensive physical properties for a

sample of a pure substance remain constant. ex. pure water- always a colorless liquid

that boils at 100ºC at sea level; doesn’t matter if you have 10 mL or 1 L

Melting and boiling point are examples of these constant physical properties. can be used to help identify a substance

Extensive vs. IntensiveExamples:

boiling pointvolumemassdensityconductivity

intensiveextensiveextensiveintensiveintensive

Density – a physical property Derived units =

Combination of base units

Volume (m3 or cm3 or mL) length length length Or measured using a

graduated cylinder

D = MV

1 cm3 = 1 mL1 dm3 = 1 L

Density (kg/m3 or g/cm3 or g/mL)mass per volume

DensityM

ass

(g)

Volume (cm3)

ΔxΔyslope D

VM

Density An object has a volume of 825 cm3 and a

density of 13.6 g/cm3. Find its mass.

GIVEN:V = 825 cm3

D = 13.6 g/cm3

M = ?

WORK:M = DV

M = (13.6 g/cm3)(825cm3)

M = 11,220 g

M = 11,200 gVMD

Density A liquid has a density of 0.87 g/mL. What

volume is occupied by 25 g of the liquid?

GIVEN:D = 0.87 g/mLV = ?M = 25 g

WORK:V = M D

V = 25 g 0.87 g/mL

V = 29 mLVMD

= 28.736 mL

Chemical PropertiesChemical Property

describes the ability of a substance to undergo changes in identity

Physical vs. Chemical PropertiesExamples:

melting pointflammabledensitymagnetictarnishes in air

physicalchemicalphysicalphysicalchemical

Physical ChangesPhysical Change

changes the form of a substance without changing its identity

properties remain the sameEx: cutting a sheet of paper, breaking

a crystal, all phase changes

Some Physical ChangesBoilingCondensationDissolvingEvaporationFreezingMeltingSublimation

Phase Changes – Physical Evaporation =

Condensation =

Melting =

Freezing =

Sublimation =

Liquid -> Gas

Gas -> Liquid

Solid -> Liquid

Liquid -> Solid

Solid -> Gas

Chemical ChangesProcess that involves one or more

substances changing into a new substanceCommonly referred to as a chemical

reactionNew substances have different

compositions and properties from original substances

Chemical ChangesSigns of a Chemical Change

change in color or odorformation of a gasformation of a precipitate (solid)change in light or heat

Change of Energy

All physical & chemical changes involve a change of energy.

• Endothermic – energy absorbed• a positive number (+) means endothermic• feel cold to the touch

• Exothermic – energy released • a negative number (-) means exothermic• feel warm or hot to the touch

Some Chemical Changes Combustion Corrosion Electrolysis Fermentation Metabolism Photosynthesis Bubble formation Temperature change Smell Rust

Tip for Distinguishing Is the change permanent? Can I get

the original substance back after the change?” If so, it is a physical change. If not, it is a chemical change.

Physical vs. Chemical ChangesExamples:

rusting irondissolving in waterburning a logmelting icegrinding spices

chemicalphysicalchemicalphysicalphysical

What Type of Change?

What Type of Change?

Law of Conservation of MassAlthough chemical changes occur,

mass is neither created nor destroyed in a chemical reaction

Mass of reactants equals mass of products

massreactants = massproducts

A + B C

Conservation of Mass In an experiment, 10.00 g of red mercury (II) oxide powder is

placed in an open flask and heated until it is converted to liquid mercury and oxygen gas. The liquid mercury has a mass of 9.26 g. What is the mass of the oxygen formed in the reaction?

Mercury (II) oxide mercury + oxygenMmercury(II) oxide = 10.00 gMmercury = 9.26Moxygen = ?

GIVEN:Mercury (II) oxide mercury + oxygenMmercury(II) oxide = 10.00 gMmercury = 9.86 gMoxygen = ?

WORK:10.00 g = 9.86 g + moxygen

Moxygen = (10.00 g – 9.86 g)

Moxygen = 0.74 g

massreactants = massproducts

Matter Flowchart

MATTERCan it be physically

separated?

Homogeneous Mixture

(solution)

Heterogeneous Mixture Compound Element

MIXTURE PURE SUBSTANCE

yes no

Can it be chemically decomposed?

noyesIs the composition uniform?

noyes

Matter FlowchartExamples:

graphitepeppersugar (sucrose)paintsoda

elementhetero. mixturecompoundhetero. mixturesolution

Pure SubstancesElement

composed of identical atomsEX: copper wire, aluminum foil

Pure SubstancesCompound- ex. table salt (NaCl)

composed of 2 or more elements in a fixed ratio

properties differ from those of individual elements

Molecule smallest particle of a compound

Mixtures Variable combination of 2 or more pure substances that

is physically combined. There is no particular ratio and each part of the mixture

keeps its own properties. Ex. Perfume, potting soil, salad dressings, and tea.

Heterogeneous Homogeneous

MixturesSolution

Homogeneous mixturevery small particlessubstances are in the same amount in all

parts of the mixtureparticles don’t settleex. rubbing alcohol, perfume

MixturesHeterogeneous

medium-sized to large-sized particles

substances in the mixture are not evenly mixed

particles may or may not settle

ex. milk, fresh-squeezed lemonade, salad

dressing, potting

soil

Heterogeneous Mixtures

Colloid: a heterogeneous mixture with larger particles that never settle; scatter light in the Tyndall effect. Ex. Milk

Suspension: a heterogeneous mixture containing a liquid in which visible particles settle

MixturesExamples:

teamuddy waterfogsaltwaterItalian salad dressing

Answers:SolutionHeterogeneousHeterogeneousSolutionHeterogeneous

Separating Mixtures Substances in a mixture are physically

combined, so processes based on differences in physical properties are used to separate component

Numerous techniques have been developed to separate mixtures to study components

FiltrationDistillationCrystallizationChromatography

Filtration Used to separate

heterogeneous mixtures composed of solids and liquids

Uses a porous barrier to separate the solid from the liquid

Liquid passes through leaving the solid in the filter paper

DistillationUsed to separate

homogeneous mixtures

Based on differences in boiling points of substances involved

Crystallization Separation technique resulting in

the formation of pure solid particles from a solution containing the dissolved substance

As one substance evaporates, the dissolved substance comes out of solution and collects as crystals

Produces highly pure solids Ex. Rocky candy

Chromatography Separates components of a mixture based on

ability of each component to be drawn across the surface of another material

Mixture is usually liquid and is usually drawn across chromatography paper

Separation occurs because various components travel at different rates

Components with strongest attraction for paper travel the slowest