Chemistry 11Chemistry 11Unit 3Unit 3

The Physical Properties The Physical Properties

and Physical Changes of and Physical Changes of SubstancesSubstances

What We What We Hope Hope

to Learn This Unit to Learn This Unit Review some basic definitions used in Chemistry and Science. Learn

to use these definitions and be able to give examples of each, and explain the relationships between them

Identify matter by its physical/ intensive properties Classify all matter based on their atomic/physical properties

(element, compound, solution, mechanical mixture) and give examples from each category (justify example choice)

Describe the characteristics of matter Select an appropriate way of physically separating the components

of different mixtures (Hand separation, Chromatography, Distillation, Solvent Extraction, Gravity Separation, Filtration, Crystallization, Evaporation)

Describe the differences between physical and chemical changes and give examples of each.

Identify the difference between a mixture or a pure substance by its graphed heating/cooling curve/phase diagram

Scientific Method SongScientific Method Song

http://www.youtube.com/watch?v=3Ihttp://www.youtube.com/watch?v=3Iv70Fzxxjwv70Fzxxjw

3-1. Some Basic Definitions in 3-1. Some Basic Definitions in ScienceScience

A.Description• Series of observations used to characterise

something• List of properties of something

B. Data• Quantitative information, experimentally determined

C. Experiment• Test or procedure done answer a question or problem

D. Observations:• The use of all of the senses (sight, taste, smell,

hearing and touch) to gather information from and about your surroundings

E. Interpretation: Is an inference based on an observation.

Brings meaning to an observation. Two types:

1. Qualitative information is non-numerical information.

2. Quantitative information is numerical information.

ExampleExample QualitativeQualitative

DescriptionDescriptionQuantitativeQuantitative

DescriptionDescription

Your heightYour height tall, shorttall, short 180 cm180 cm

Your weightYour weight thin, heavythin, heavy 123 kg123 kg

F. F. InferenceInference: : Generally, we draw an inference when Generally, we draw an inference when

we go beyond stated information by we go beyond stated information by applying our background knowledge. applying our background knowledge.

For example, if we learn that John ran a red light For example, if we learn that John ran a red light and is being treated for injuries at the local and is being treated for injuries at the local

hospital, we can reasonably draw an inference hospital, we can reasonably draw an inference that he was injured in an accident that he was injured in an accident

G.G. Prediction Prediction::

• A prediction is the act of reasoning about the A prediction is the act of reasoning about the future based on past experience. For example, future based on past experience. For example, we can confidently predict that day will follow we can confidently predict that day will follow night.night.

H. H. HypothesisHypothesis

A hypothesis is a tentative statement A hypothesis is a tentative statement that proposes a possible explanation that proposes a possible explanation to some phenomenon or event. A to some phenomenon or event. A useful hypothesis is a useful hypothesis is a testable testable statement which may include a statement which may include a prediction.prediction.

When Are Hypotheses Used?When Are Hypotheses Used?

The key word is The key word is testabletestable. That is, you will . That is, you will perform a test of how two variables might perform a test of how two variables might be related.be related.

This is when you are doing a real This is when you are doing a real experiment. You are testing variables. experiment. You are testing variables. Usually, a hypothesis is based on some Usually, a hypothesis is based on some previous observation such as noticing that previous observation such as noticing that in November many trees undergo color in November many trees undergo color changes in their leaves and the average changes in their leaves and the average daily temperatures are dropping. Are these daily temperatures are dropping. Are these two events connected? How?two events connected? How?

Formalized Hypotheses Formalized Hypotheses example:example:

If If skin cancerskin cancer is is related related to to ultraviolet lightultraviolet light , , then then people with a people with a high exposure to uv light will have a high exposure to uv light will have a higher frequency of skin cancerhigher frequency of skin cancer..

If If leaf color changeleaf color change is is related related to to temperaturetemperature , , then then exposing plants exposing plants to low temperatures will result in to low temperatures will result in changes in leaf color.changes in leaf color.

Formalized hypotheses contain two Formalized hypotheses contain two variables. variables.

One is "independent" and the other One is "independent" and the other is "dependent." is "dependent."

The independent variable is the one The independent variable is the one you, the "scientist" control and the you, the "scientist" control and the dependent variable is the one that dependent variable is the one that you observe and/or measure the you observe and/or measure the results. results.

In the statements above the In the statements above the dependent variable is bluedependent variable is blue and the and the independent variable is red.independent variable is red.

A 500 ml. beaker is placed on a counter at one side of A 500 ml. beaker is placed on a counter at one side of the classroom. The beaker is filled to about half full the classroom. The beaker is filled to about half full with a liquid and allowed to remain there for one week. with a liquid and allowed to remain there for one week. During this time you make as many observations and During this time you make as many observations and related statements about the beaker and contents as related statements about the beaker and contents as you can. Listed below are some statements that have you can. Listed below are some statements that have been made by others. Read their statements and been made by others. Read their statements and

identify which are identify which are observationsobservations, , inferencesinferences or or hypotheseshypotheses..

Practicing to identify hypotheses, inferences and observations

1.1. On the first day the volume of On the first day the volume of liquid was about 200 milliliters.liquid was about 200 milliliters.

2.2. The beaker looks and feels like The beaker looks and feels like glass.glass.

3.3. The beaker is glass.The beaker is glass.

4.4. The liquid appears clear ; you The liquid appears clear ; you can see through it.can see through it.

5.5. The liquid has a sweet odor.The liquid has a sweet odor.

6.6. Chemical analysis would reveal Chemical analysis would reveal the presence of peppermint oil the presence of peppermint oil in the liquid.in the liquid.

7. All clear, transparent liquids have 7. All clear, transparent liquids have a sweet odor. a sweet odor.

8. On the third day the volume of 8. On the third day the volume of the liquid was 100 mlthe liquid was 100 ml

9. 100 ml. of the liquid must have 9. 100 ml. of the liquid must have evaporated during the first three evaporated during the first three days.days.

10. Someone drank 100 ml. of the 10. Someone drank 100 ml. of the liquid during the first three days. liquid during the first three days.

11. Liquids decrease in volume 11. Liquids decrease in volume when allowed to stand in an open when allowed to stand in an open container for any length of time.container for any length of time.

..

I.I. Scientific theory: Scientific theory: summarizes a hypothesis or group of summarizes a hypothesis or group of

hypotheses that have been supported with hypotheses that have been supported with repeated testing. repeated testing.

One definition of a theory is to say it's an One definition of a theory is to say it's an accepted hypothesis. accepted hypothesis.

It can be used to explain something. It can be used to explain something.

J. A J. A law:law: generalizes a body of observations. generalizes a body of observations. At the time it is made, no exceptions have At the time it is made, no exceptions have

been found to a law. been found to a law. Scientific laws explain things, but they Scientific laws explain things, but they do not do not

describe themdescribe them. One way to tell a law and a . One way to tell a law and a theory apart is to ask if the description gives theory apart is to ask if the description gives you a means to explain 'why'. you a means to explain 'why'.

HypothesiHypothesiss

TheoryTheory LawLaw

Single ideaSingle idea yesyes nono nono

Testable predictionTestable prediction yesyes yesyes nono

A temporary ideaA temporary idea yesyes nono nono

AssumptionAssumption yesyes nono nono

Broad generalizationsBroad generalizations NoNo YesYes Yes Yes

Explains WHY Explains WHY something occurssomething occurs

nono yesyes nono

Summarizes past Summarizes past results of experimentsresults of experiments

nono nono yesyes

Predicts what will Predicts what will happen in NEW happen in NEW situations situations

NoNo yesyes nono

Predicts what will Predicts what will always happen in a always happen in a KNOWN situationKNOWN situation

No No No No yesyes

Assignment: Assignment: Ex.) 1, 2, 3, 5, 6, 8, 9, 11Ex.) 1, 2, 3, 5, 6, 8, 9, 11

3-2. The Physical Properties of 3-2. The Physical Properties of MatterMatter

Matter:Matter: Anything that has mass and occupies spaceAnything that has mass and occupies space If it is not matter it is ENERGY (which is also If it is not matter it is ENERGY (which is also

observable)observable) SubstanceSubstance::

A unique and identifiable set of propertiesA unique and identifiable set of properties Chemical Chemical PropertyProperty::

the ability of a substance to undergo chemical the ability of a substance to undergo chemical reactions and change into a new substancereactions and change into a new substance

Physical Physical PropertyProperty:: Can be found without creating a new Can be found without creating a new

substancesubstance

There ARE TWO TYPES OF PHYSICAL PROPERTIES:

1.Extensive Physical Property:

• depends on the amount of substance present• NOT used to identify a substance

2.Intensive Physical Property:

• depends on the nature of the substance• does NOT depend on how much is present• used to identify substances

ExamplesExamples Intesive or Intesive or Extensive?Extensive?

DensityDensity II

ColourColour II

SmellSmell II

Melting pointMelting point II

Mass Mass EE

TemperatureTemperature II

VolumeVolume EE

SolubilitySolubility II

States of MatterStates of Matter

Solid

Liquid

Gas

Definite Volume?

YES

YES

NO

Definite Shape?

YES

NO

NO

Temp. increase

Small Expans.

Small Expans.

Large Expans.

Com-pressible?

NO

NO

YES

Solid Liquid Gas

Melt Evaporate

CondenseFreeze

States of MatterStates of Matter

There are moreThere are more PlasmaPlasma

high temperature low pressure high temperature low pressure electrons separate from nucleuselectrons separate from nucleus Most common in the universeMost common in the universe

More at very low tempMore at very low temp Bose- Einstein condensateBose- Einstein condensate Quantum superfluidsQuantum superfluids

Physical properties definitionsPhysical properties definitions::

HardnessHardness the ability to resist abrasion or scratchingthe ability to resist abrasion or scratching

MalleabilityMalleability the ability to be rolled or shaped into thin the ability to be rolled or shaped into thin

sheetssheets DuctilityDuctility

the ability to be stretched or drawn into the ability to be stretched or drawn into wireswires

LustreLustre the manner in which a solid reflects lightthe manner in which a solid reflects light Terms include: metallic, adamantine, Terms include: metallic, adamantine,

glassy, oily, pearly, silky or dullglassy, oily, pearly, silky or dull

ViscosityViscosity the resistance of a fluid to flow (low = the resistance of a fluid to flow (low =

fast, high = slow)fast, high = slow) DiffusionDiffusion

the intermingling of fluids as a result of the intermingling of fluids as a result of motion within the fluid (gases and liquids)motion within the fluid (gases and liquids)

VapourVapour gaseous material formed by the gaseous material formed by the

evaporation of a substance which boils evaporation of a substance which boils above room temperatureabove room temperature

If a substance boils below room If a substance boils below room temperature it is called a gas (see the temperature it is called a gas (see the periodic table)periodic table)

Vapour pressureVapour pressure the pressure created by the vapour the pressure created by the vapour

evaporating from a liquidevaporating from a liquid

Ductile MalleableLustre

Viscosity

Diffusion

Hardness

Assignment: Assignment: Ex.) 13, 14, 15, 17 (not ‘e’), 18, Ex.) 13, 14, 15, 17 (not ‘e’), 18, 19, 20, 21, 22, 24, 29, and 3119, 20, 21, 22, 24, 29, and 31

3-3. The Classification of Matter3-3. The Classification of Matter

DefinitionsDefinitions:: ParticleParticle

A general term used to describe a small bit of A general term used to describe a small bit of mattermatter

AtomAtom The smallest possible unit of an element which The smallest possible unit of an element which

retains the fundamental properties of the elementretains the fundamental properties of the element ElementElement

A substance which cannot be separated into A substance which cannot be separated into simpler substance as a result of any CHEMICAL simpler substance as a result of any CHEMICAL processprocess

Only 1 type of atoms presentOnly 1 type of atoms present

MoleculeMolecule a cluster of 2 or more atoms held a cluster of 2 or more atoms held

together strongly by electrical forcestogether strongly by electrical forces CompoundCompound

A pure substance made of more than 1 A pure substance made of more than 1 type of atomtype of atom

Only one type of molecule is a Only one type of molecule is a compoundcompound

If a single If a single particle is a/an:particle is a/an:

Then a large-Then a large-scale, visible scale, visible collection of collection of

these particles these particles is called:is called:

AtomAtomoror

Molecule made of Molecule made of identical atomsidentical atoms

ElementElement

Molecules made of Molecules made of different atomsdifferent atoms

CompoundCompound

What is an ion?What is an ion?

An atom is a netural particle because it An atom is a netural particle because it contains an equal number of electrons contains an equal number of electrons (neg charge) and protons (positive (neg charge) and protons (positive charge)charge)

In an ion, the number of elctons has changed. In an ion, the number of elctons has changed. Atoms GAIN or LOSE elctrons to become more Atoms GAIN or LOSE elctrons to become more stable (a full outer shell). The number of protons stable (a full outer shell). The number of protons NEVER change, only the number of electonsNEVER change, only the number of electons

What is the charge of the ion?What is the charge of the ion?

AtomAtom Change in Change in electronselectrons

Ion chargeIon charge

AlAl Lost 3Lost 3 +3+3

OO Gained 2Gained 2 -2-2

CuCu Lost 1Lost 1 +1+1

BrBr Gained 1Gained 1 -1-1

PP Gained 3Gained 3 -3-3

Classification of matterClassification of matter

SystemSystem: the part of the universe being : the part of the universe being studied in a given situationstudied in a given situation

PhasePhase: is any part of a system which is : is any part of a system which is UNIFORM in both its composition and UNIFORM in both its composition and propertiesproperties

Homogenous SubstanceHomogenous Substance substance with only 1 phasesubstance with only 1 phase

Pure substancePure substance homogenous + unchangeable and homogenous + unchangeable and

uniform compositionuniform composition Compound Compound

ElementElement

Homogeneous MixtureHomogeneous Mixture made up of 2 or more substances made up of 2 or more substances

(uniform composition ) in varied (uniform composition ) in varied amounts,amounts,

SolutionSolution homogeneous mixture of 2 or more homogeneous mixture of 2 or more

substancessubstances

Solution ReviewSolution Review

Aqueous Aqueous (solvent is water)(solvent is water) SolventSolvent (does the dissolving/exist in (does the dissolving/exist in

the greater quantity)the greater quantity) SoluteSolute (is dissolved/exist as the (is dissolved/exist as the

smaller quantity)smaller quantity)

Heterogeneous SubstanceHeterogeneous Substance substance with more then one phase (different substance with more then one phase (different

physical properties)physical properties) Mechanical MixtureMechanical Mixture

Heterogeneous mixture of 2 or more Heterogeneous mixture of 2 or more visiblevisible substancessubstances

Suspensions (milk, blood, Ketchup, OJ, TJ)Suspensions (milk, blood, Ketchup, OJ, TJ) Precipitates (OJ with pulp, TJ with pulp, Silty Precipitates (OJ with pulp, TJ with pulp, Silty

water)water)

Classification of SubstancesClassification of SubstancesAll Substances

Homogeneous Substances

Heterogeneous Substances

Pure SubstanceHomogeneous

Mixture

Element (1 type of atom present)

Solution

Compound (More then 1 type of

atom present)

Mechanical Mixtures

Assignment: Ex.) 33 - 44Assignment: Ex.) 33 - 44

3-43-4 The Physical Separation of The Physical Separation of SubstancesSubstances

The methods examined in this The methods examined in this section take advantage of differences section take advantage of differences in the physical properties of the in the physical properties of the substances involved substances involved

A.Mechanical Mixtures

MixtureMixture MethodMethod When to Use MethodWhen to Use Method

Solid in Solid in SolidSolid(Heterogeneou(Heterogeneous)s)

Hand SeparationHand Separation Large chunks present Large chunks present among other solidsamong other solids

Gravity Gravity SeparationSeparation

The density of the desired The density of the desired solids is much different solids is much different form the density of the form the density of the other solids.other solids.

Solvent Solvent ExtractionExtraction

One solid preferentially One solid preferentially dissolves in a particular dissolves in a particular solvent.solvent.

ChromatographyChromatography The solids are coloured, The solids are coloured, present in small amounts present in small amounts and are soluble in some and are soluble in some solvent or mixture of solvent or mixture of solventssolvents

Solid in Solid in LiquidLiquid(Heterogeneou(Heterogeneous)s)

Hand Hand SeparationSeparation

A few large pieces of solid A few large pieces of solid are present in the liquid.are present in the liquid.

Gravity Gravity SeparationSeparation

Solid particles are present Solid particles are present in a small amount of in a small amount of liquid.liquid.

FiltrationFiltration Solid particles are present Solid particles are present in a large amount of in a large amount of liquid.liquid.

B. SolutionsB. SolutionsMixtureMixture MethodMethod When to Use MethodWhen to Use Method

Solid in LiquidSolid in Liquid(Homogeneou(Homogeneou

s)s)

EvaporationEvaporation The solid is wanted and the The solid is wanted and the liquid is not.liquid is not.

DistillationDistillation The liquid is wanted; the solid The liquid is wanted; the solid may or may not be wanted.may or may not be wanted.

MixtureMixture MethodMethod When to Use MethodWhen to Use Method

Solvent ExtractionSolvent Extraction An immiscible added solvent An immiscible added solvent preferentially dissolves at preferentially dissolves at least one but not all the solids least one but not all the solids present.present.

MixtureMixture MethodMethod When to Use MethodWhen to Use Method

RecrystillizationRecrystillization One dissolved solid is much less One dissolved solid is much less soluble than the others soluble than the others present (if any); the liquid is present (if any); the liquid is not wanted.not wanted.

ChromatographyChromatography Small amounts of the more than Small amounts of the more than one coloured solid are present; one coloured solid are present; the liquid present is not the liquid present is not wanted.wanted.

Liquid in Liquid in LiquidLiquid(Homogeneou(Homogeneous)s)

DistillationDistillation Two or more liquids Two or more liquids are present and have are present and have different boiling different boiling temperatures.temperatures.

Solvent Solvent ExtractionExtraction

An immiscible added An immiscible added solvent preferentially solvent preferentially dissolves at least one dissolves at least one but not all of the but not all of the liquids present.liquids present.

Assignment: Ex.) 45, 46, 47, 51, Assignment: Ex.) 45, 46, 47, 51, 52, 53, 57 and 5852, 53, 57 and 58

3-5 Phase Changes3-5 Phase Changes Chemical and Physical ChangesChemical and Physical Changes::

CHEMICAL CHANGE:CHEMICAL CHANGE: A change in which new substances are formed.A change in which new substances are formed. Produces a set of chemicals which is different Produces a set of chemicals which is different

from the set of chemicals which existed before from the set of chemicals which existed before the change.the change.

Examples include:Examples include: Noticeable heat or light is produced.Noticeable heat or light is produced. A colour change is observed.A colour change is observed. One of the original materials is used up.One of the original materials is used up. Bubbles may appear, which shows that a new gas Bubbles may appear, which shows that a new gas

may be forming.may be forming. Cloudiness may result; this shows that a solid is Cloudiness may result; this shows that a solid is

forming (a precipitate).forming (a precipitate).

PHYSICAL CHANGE:PHYSICAL CHANGE: A change in the A change in the phasephase of a of a

substance, such that no new substance, such that no new substances are formed.substances are formed.

A physical change does not change A physical change does not change the set of chemicals involved.the set of chemicals involved.

Examples:Examples: Solid chunkSolid chunk powder powder DissolvingDissolving Any phase changeAny phase change

Phase changesPhase changes::MELTING TEMPERATURE (MP)MELTING TEMPERATURE (MP)

The temperature where solid changes to liquidThe temperature where solid changes to liquid

FREEZING TEMPERATURE (FP)FREEZING TEMPERATURE (FP) The temperature where liquid changes to solid.The temperature where liquid changes to solid. At the MELTING/FREEZING TEMPERATURE, the solid and At the MELTING/FREEZING TEMPERATURE, the solid and

liquid phases co-exist.liquid phases co-exist.

BOILING TEMPERATURE (BP)BOILING TEMPERATURE (BP) The temperature where liquid changes to gas.The temperature where liquid changes to gas.

CONDENSATION TEMPERATURE (CP)CONDENSATION TEMPERATURE (CP) The temperature where gas changes to liquid.The temperature where gas changes to liquid. At the BOILING/CONDENSATION TEMPERATURE, the At the BOILING/CONDENSATION TEMPERATURE, the

liquid and gas phases co-existliquid and gas phases co-exist..

NOTE: The temperature does not change during a NOTE: The temperature does not change during a phase change (such as melting and boiling).phase change (such as melting and boiling).

Continued heating of a pure solid substance produces the following temperature behavior

There is a steady decrease in the amount There is a steady decrease in the amount of solid as the amount of liquid increases. of solid as the amount of liquid increases. At the start of the phase change the At the start of the phase change the substance is 100% solid, then more and substance is 100% solid, then more and more liquid forms. Eventually, the last bit more liquid forms. Eventually, the last bit of solid melts and the phase change is of solid melts and the phase change is complete as shown by the graph below:complete as shown by the graph below:

Assignment: Ex.) 64 - 71Assignment: Ex.) 64 - 71