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

Matter

Matter – anything that has mass and takes up space

Everything around us

Chemistry – the study of matter and the changes it undergoes

Substances

Atoms: 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 Matter

Gasesparticles can separate and

move throughout containervariable 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 Properties

Physical Propertycan be observed without changing the

identity of the substance

Physical Properties

Physical properties can be described as one of 2 types:

Extensive Propertydepends on the amount of matter

present (example: length)

Intensive Propertydepends on the identity of substance, not

the amount (example: scent)

Intensive Physical Properties

The 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. Intensive

Examples:boiling point

volume

mass

density

conductivity

intensive

extensive

extensive

intensive

intensive

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)

Δx

Δyslope D

V

M

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 gV

MD

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/mL

V = ?

M = 25 g

WORK:

V = M D

V = 25 g

0.87 g/mL

V = 29 mLV

MD

= 28.736 mL

Chemical Properties

Chemical Propertydescribes the ability of a substance to

undergo changes in identity

Physical vs. Chemical Properties

Examples:melting point

flammable

density

magnetic

tarnishes in air

physical

chemical

physical

physical

chemical

Physical Changes

Physical Changechanges the form of a substance

without changing its identityproperties remain the same

Ex: cutting a sheet of paper, breaking a crystal, all phase changes

Some Physical Changes

BoilingCondensationDissolvingEvaporationFreezingMeltingSublimation

Phase Changes – Physical

Evaporation =

Condensation =

Melting =

Freezing =

Sublimation =

Liquid -> Gas

Gas -> Liquid

Solid -> Liquid

Liquid -> Solid

Solid -> Gas

Chemical Changes

Process 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 Changes

Signs of a Chemical Changechange in color or odor

formation of a gas

formation 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 Changes

Examples:rusting iron

dissolving in water

burning a log

melting ice

grinding spices

chemical

physical

chemical

physical

physical

What Type of Change?

What Type of Change?

Law of Conservation of Mass

Although 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 + oxygen

Mmercury(II) oxide = 10.00 g

Mmercury = 9.86 g

Moxygen = ?

WORK:10.00 g = 9.86 g + moxygen

Moxygen = (10.00 g – 9.86 g)

Moxygen = 0.74 g

massreactants = massproducts

Matter Flowchart

MATTER

Can 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 Flowchart

Examples:graphite

pepper

sugar (sucrose)

paint

soda

element

hetero. mixture

compound

hetero. mixture

solution

Pure Substances

Elementcomposed of identical atomsEX: copper wire, aluminum foil

Pure Substances

Compound- 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

Mixtures

Solution Homogeneous mixturevery small particlessubstances are in the same amount in all

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

Mixtures

Heterogeneousmedium-sized to large-

sized particlessubstances 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

Mixtures

Examples:tea

muddy water

fog

saltwaterItalian 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

Distillation

Used 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