Unit 2: Matter

Matter

Anything that has mass and takes up space (volume)

Matter resist change (inertia) Matter has the capacity to do work

(energy)

Law of Conservation of Matter

Matter is neither created or destroyed in a chemical reaction.

Also referred to as the Law of Conservation of Mass

Physical Property

Can be observed with the senses or measured without changing the substance

Examples: Melting point Boiling point Color/shape Density Mass

Physical Properties can be

ExtensiveDepends on the amount of matter

Mass Length Volume Time to boil

IntensiveDoes not depend on

amount of matter Density Color Boiling point Melting point

Physical Change

A change that does not involve altering the identity of the substance

Examples: Freezing Melting Boiling Cutting Grinding

Chemical Property

Relates to a substance’s ability to undergo a change into a different substance

Examples: Ability to rust Flammable Ability to react

with an acid Decomposes in

light

Chemical Change

A change where one or more substances is converted into different substances (a chemical reaction)

Examples: Rotting Burning Fermenting Cooking

4 indicators of a chemical change

Color ChangeEvolution of heat or lightProduction of gasFormation of a precipitate

Precipitate: A solid that forms from

solution

Chemical change = chemical reaction and is written as

Reactants Products

This is whatyou startwith

This iswhat youend with

Classifying MatterClassifying Matter

Matter

ElementsCompound

sMixtures

• Scientists classify matter according to make-up.

ElementsElements

• Simplest pure substance – fixed composition.

• Pure substance is made of only one material. Same throughout. Referred to as homogeneous matter.

• Are made of alike atoms, which are the basic building blocks of matter.

• Represented by chemical symbols - H, O, Al, Cu, Au.

• 118 elements organized in the periodic table in squares called an element key.

CompoundsCompounds

• Two or more elements chemically combined.

• Represented by chemical formulas.

• Examples: H2O, CO2, NaCl, C12H22O11

• Molecules are the smallest natural unit of a compound or diatomic element. A molecule is made up of two or more atoms chemically combined.

MixturesMixturesMixturesMixtures

• Two or more substances mixed together but not chemically combined.

• Has unlike parts and a composition that varies from sample to sample.

• Properties:

– Sub. in a mixture keep their separate identities.

– Sub. can be present in any amount.

– Sub. can be separated out by physical means.

Materials

MixturesMixtures

Matter that contains Matter that contains more than one more than one materialmaterial

HomogeneousHomogeneous HeterogeneousHeterogeneous

PurePure SubstancesSubstances

One part is One part is representative of representative of the wholethe whole

ElementElement CompoundCompound

Mixtures: Variable combination of two or more

substances:

Homogeneousuniform throughout

Heterogeneousnot uniform throughout

MixturesMixtures

Mixtures

Homogeneous Heterogeneous

Elements and Compounds

An element is the simplest form of matter and has a unique set of properties.

A compound contains two or more elements chemically combined in fixed proportions.

Compounds can be broken down, elements cannot.

Pure Substances: Elements are Composed of identical

atoms

Chlorine gas

Sodium metal

2 or More Elements Combine to Produce a Compound

Chlorine gas +

Sodium metal

+

=

=

Sodium Chloride

Used to describe any part of a Used to describe any part of a sample with uniform composition and sample with uniform composition and propertiesproperties

Heterogeneous: 2 or more phasesHeterogeneous: 2 or more phases Homogeneous: 1 phaseHomogeneous: 1 phase

PhasePhase

The distinction between The distinction between solutions and solutions and

heterogeneous mixtures heterogeneous mixtures can be difficult can be difficult

especially in the liquid especially in the liquid phase.phase.

The distinction between The distinction between solutions and solutions and

heterogeneous mixtures heterogeneous mixtures can be difficult can be difficult

especially in the liquid especially in the liquid phase.phase.

SolutionsSolutions

• A homogeneous mixture.

• One substance dissolves in another. Solutions remain constantly & uniformly mixed.

•Solute and Solvent

•Particles are smaller than 1 nm in size

•Particles do not settle

•Particles pass through filter paper

Examples: lemonade, soda, ocean water, antifreeze, metal alloys

A homogeneous mixture combining A homogeneous mixture combining two or more metals to maximize the two or more metals to maximize the benefits of each. benefits of each.

Ex. Gold Jewelry: 14 kt Gold (Gold for Ex. Gold Jewelry: 14 kt Gold (Gold for shine, Silver for strength)shine, Silver for strength)

AlloyAlloy

ColloidsColloidsColloidsColloids

• A homogeneous mixture.

• Mixed together but not dissolved.

• Appears cloudy. Scatters light.

•Particles are 2 – 100 nm in size

•Particles do not settle

•Particles pass through filter paper

•Usually not transparent (cloudy)

• Examples: milk, cool whip, toothpaste, lotions, fog, smoke, Jello.

Heterogeneous MixtureHeterogeneous Mixture Particles settle to the bottom unless Particles settle to the bottom unless

constantly stirredconstantly stirred Particles are greater than 100 nmParticles are greater than 100 nm Not transparent, must be mixedNot transparent, must be mixed Ex: Paint, Chocolate Milk, Ex: Paint, Chocolate Milk,

SuspensionSuspension

Composition of MatterComposition of Matter

E lem e nt C o m p ou nd

P u re S u bs tan ce

S o lu tion C o lliod

H o m o ge n eo us

S usp en sion

H e te rog en eo us

M ixtu re

M atte r

Separating Mixtures

Filtration

Separates a solid Separates a solid from a liquid in a from a liquid in a heterogeneous heterogeneous mixturemixture

Mixture passes Mixture passes through filter paper through filter paper

Can sieve for larger Can sieve for larger piecespieces

Filter paper for finer Filter paper for finer pieces or powderspieces or powders

Distillation

A liquid is boiled to A liquid is boiled to produce a vapor, produce a vapor, which is then which is then turned back into a turned back into a liquid through a liquid through a condensation tube. condensation tube.

Substances that Substances that dissolve in water dissolve in water remain in flaskremain in flask

Decanting

After solid settles After solid settles to bottom of to bottom of container, the container, the liquid is carefully liquid is carefully poured off the toppoured off the top

Chromatography

Way to separate mixturesWay to separate mixtures General Chemistry Online Chromatography Web Animation

Centrifuge Separates solid Separates solid

from solution by from solution by spinning and spinning and pushing the solid pushing the solid to the bottom of to the bottom of the containerthe container