Chemistry 2Chemistry 2Chapter 2Chapter 2

Matter and ChangeMatter and Change

Properties of Matter 2.1Properties of Matter 2.1

What would you like to know about the extensive and intensive properties of bamboo?

What characteristic makes bamboo useful for cooking tools?

FYI: Characters on the chop sticks translate as good fortune, prosperity, longevity, and good health.

Describing Matter – 2.1Describing Matter – 2.1Matter – anything that takes up spaceMatter – anything that takes up spaceMass – amount of matter the object containsMass – amount of matter the object containsVolume – Space occupied by objectVolume – Space occupied by objectExtensive Property Extensive Property

Depends on the amount of matter in a sampleDepends on the amount of matter in a sampleVolume and MassVolume and Mass

Intensive Intensive Depends on the type of matter in a sample, not the Depends on the type of matter in a sample, not the

amountamount

Identify Substance 2.1Identify Substance 2.1Substance – matter that has a uniform and Substance – matter that has a uniform and

definite compositiondefinite compositionEvery sample of same substance is identicalEvery sample of same substance is identical

Physical Property – quality or condition of a Physical Property – quality or condition of a substance that can be OBSERVED or substance that can be OBSERVED or MEASURED MEASURED without changing without changing substancesubstanceEx: hardness, color, conductivity, malleability, Ex: hardness, color, conductivity, malleability,

melting point, boiling pointmelting point, boiling pointHelp ID substanceHelp ID substance

Copper vs. GoldCopper vs. GoldPhysical Property DifferencesPhysical Property Differences

Copper Copper Scratch surface of pure gold (harder than gold)Scratch surface of pure gold (harder than gold) Better conductor of heat/electricityBetter conductor of heat/electricity MalleableMalleable Reddish-yellowReddish-yellow MP = 1084 CelsiusMP = 1084 Celsius BP = 2562 CelsiusBP = 2562 Celsius

GoldGold More malleableMore malleable YellowYellow MP = 1054 CelsiusMP = 1054 Celsius BP = 2856 CelsiusBP = 2856 Celsius

States of Matter – 2.1States of Matter – 2.1 Visualize the structure of solids, liquids, and gases Visualize the structure of solids, liquids, and gases

at the microscopic level…at the microscopic level…

1.1. SolidsSolids – definite shape and volume – definite shape and volume Particles packed tightly togetherParticles packed tightly together

2.2. Liquids Liquids – indefinite shape, flows, but fixed volume– indefinite shape, flows, but fixed volume Tend to expand when heatedTend to expand when heated Incompressible (mostly)Incompressible (mostly)

3.3. Gases - Gases - takes shape and volume of container takes shape and volume of container Gas – exists in gaseous state at room temp.Gas – exists in gaseous state at room temp. Vapor – gaseous state of substance that genarlly Vapor – gaseous state of substance that genarlly

solid/liquid at room temp.solid/liquid at room temp.

Physical Changes 2.1Physical Changes 2.1 Composition of martial does NOT CHANGE, physical Composition of martial does NOT CHANGE, physical

properties may changeproperties may change Boil, freeze, melt, condense, break, split, grind, cut, Boil, freeze, melt, condense, break, split, grind, cut,

crushcrush Reversible –One state of matter to anotherReversible –One state of matter to another Irreversible – cutting, cracking, etcIrreversible – cutting, cracking, etc

Look at Figure 2.4Look at Figure 2.4 What can you infer about the temperature of hand holding What can you infer about the temperature of hand holding

gallium?gallium? Is the melting of gallium a reversible or irreversible?Is the melting of gallium a reversible or irreversible? What is the physical state of gallium at room temperature?What is the physical state of gallium at room temperature?

Technology and SocietyTechnology and Society

1/3 of spiders spin webs, all produce silk1/3 of spiders spin webs, all produce silk Silk for: wrapping prey, wrapping eggs, draglines, trap Silk for: wrapping prey, wrapping eggs, draglines, trap

preyprey Silk: proteins = strong, tough, an elasticSilk: proteins = strong, tough, an elastic

FYI – OH REALLY!!!!FYI – OH REALLY!!!! A cable of golden org dragline silk that is slightly A cable of golden org dragline silk that is slightly

thicker than a garden hose would be strong enough to thicker than a garden hose would be strong enough to support two jet planes full of passengers and cargo support two jet planes full of passengers and cargo without braking!!!!!!!!!without braking!!!!!!!!!

History of silkHistory of silk Used to catch fish/birdsUsed to catch fish/birds Use as bandagesUse as bandages

Technology and SocietyTechnology and Society

Spider web 1/10 diameter of hairSpider web 1/10 diameter of hairGolden orb spider silkGolden orb spider silk

More elastic than nylonMore elastic than nylonTougher than rubberTougher than rubberStronger than steelStronger than steel

Can’t harvest b/c spider will fight to defend Can’t harvest b/c spider will fight to defend territoryterritory

Mixtures 2.2Mixtures 2.2

What is the result of panning?

What property is used to separate the mixture?

Classifying Mixtures – 2.2Classifying Mixtures – 2.2 Mixture – physical blend of 2 or more componentsMixture – physical blend of 2 or more components

most mattermost matter Ex: chicken noodle soup, airEx: chicken noodle soup, air

Heterogeneous Mixture – Heterogeneous Mixture – composition is not uniformcomposition is not uniform More than 2 phasesMore than 2 phases

Homogeneous Mixture – composition is uniform Homogeneous Mixture – composition is uniform throughout throughout ““solution” – many are liquidssolution” – many are liquids Phase – describe any part of a sample with uniform Phase – describe any part of a sample with uniform

composition composition 1 phase1 phase

Conceptual Problem 2.1 (9 and 10)Conceptual Problem 2.1 (9 and 10)

Separating Mixtures 2.2Separating Mixtures 2.2Decant – pour off (like olive oil and vinegar)Decant – pour off (like olive oil and vinegar)Cool – one part would turn solidCool – one part would turn solidFiltrationFiltration

Colander (strainer) Colander (strainer) Separates solid from liquidSeparates solid from liquid

DistillationDistillationLiquid boiled to produce a vapor that is condensed Liquid boiled to produce a vapor that is condensed

into a liquidinto a liquidFlask is heated, water vapor forms, rises in flask, Flask is heated, water vapor forms, rises in flask,

and passes into a glass tube in the condenser, tube and passes into a glass tube in the condenser, tube surrounded by cold water, turns vapor into watersurrounded by cold water, turns vapor into water

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Elements and Compounds – 2.3Elements and Compounds – 2.3

Distinguishing Elements and Distinguishing Elements and Compound 2.3Compound 2.3

Element Element – simplest form of matter with – simplest form of matter with unique set of propertiesunique set of propertiesCan not be broken downCan not be broken down

CompoundCompound – substance that contains 2 or – substance that contains 2 or more elements chemically combined in a more elements chemically combined in a fixed proportionfixed proportionCan be broken downCan be broken down

Breaking Down Compounds 2.3Breaking Down Compounds 2.3Chemical Change – change that produces Chemical Change – change that produces

matter with a different composition than matter with a different composition than the original matterthe original matterCan not use same method to SEPERATE Can not use same method to SEPERATE

mixtures as you can compoundsmixtures as you can compoundsThere are many different ways to break There are many different ways to break

down compounds (heat, electricity…),down compounds (heat, electricity…),

Properties of CompoundsProperties of CompoundsElements change physical/chemical Elements change physical/chemical

properties when mixed with other properties when mixed with other elementselementsChlorine: Use to kill harmful organisms in Chlorine: Use to kill harmful organisms in

poolspoolsSodium: Stored under oil to keep it from Sodium: Stored under oil to keep it from

reacting with oxygen – sodium vapor reacting with oxygen – sodium vapor produces the light in some street lampsproduces the light in some street lamps

Sodium chloride (table salt) season and Sodium chloride (table salt) season and preserve foodpreserve food

+ = + =

Substance vs. Mixture?????Substance vs. Mixture?????Hard to tell substance or mixture based on Hard to tell substance or mixture based on

appearanceappearanceWhole, 2% 1% ½% skim milk, light or heavy cream, Whole, 2% 1% ½% skim milk, light or heavy cream,

different blends of gasoline… can tell mixtures different blends of gasoline… can tell mixtures composition =fixed; material = composition =fixed; material = SUBSTANCESUBSTANCEComposition = varies; material = Composition = varies; material = MIXTUREMIXTUREA A MIXTUREMIXTURE is a combination of two or more is a combination of two or more

substances that are not chemically united and substances that are not chemically united and do not exist in fixed proportions to each other do not exist in fixed proportions to each other

A physical process (like evaporation or heating) A physical process (like evaporation or heating) cannot be used to breakdown a compoundcannot be used to breakdown a compound

Symbols and Formulas 2.3Symbols and Formulas 2.3Symbols represent elementsSymbols represent elements

C = CarbonC = CarbonFormulas represent compounds Formulas represent compounds

NaCl = Sodium Chloride or Table SaltNaCl = Sodium Chloride or Table SaltJons Jacob Berzelius (1779 – 1848)Jons Jacob Berzelius (1779 – 1848)

Developed symbols for elementsDeveloped symbols for elementsBased on Latin names of elementsBased on Latin names of elements

Chemical Symbols – 1 or 2 lettersChemical Symbols – 1 or 2 letters11stst letter capitalized, 2 letter capitalized, 2ndnd letter lowercase letter lowercaseSubscript – indicate relative proportions of the Subscript – indicate relative proportions of the

elements in a compoundelements in a compoundCompound = fixed; = formula is always sameCompound = fixed; = formula is always same

Chemical Reactions 2.4Chemical Reactions 2.4

What evidence do you see in the photo that a chemical reaction has occurred?

Chemical Changes 2.4Chemical Changes 2.4Chemical change words: Chemical change words: burn, rot, rust, burn, rot, rust,

decompose, ferment, explode, decompose, ferment, explode, and and corrodecorrodeChemical Property – Ability of a substance to Chemical Property – Ability of a substance to

undergo a specific chemical changeundergo a specific chemical changeObserved only when substance undergoes Observed only when substance undergoes

chemical change/ chemical reaction (matter always chemical change/ chemical reaction (matter always changes)changes)

Physical change – composition doesn’t changePhysical change – composition doesn’t change4Fe + 3O4Fe + 3O22 2Fe 2Fe22OO33

Iron + Oxygen Iron + Oxygen Iron OxideIron OxideReactant Reactant Product Product

Recognize Chemical Changes 2.4Recognize Chemical Changes 2.4 4 clues:4 clues:

1.1. Transfer of energy (methane combines with Transfer of energy (methane combines with oxygen = energy, heat, to cook food in grills)oxygen = energy, heat, to cook food in grills)

2.2. Change in color (food browns as it cooks)Change in color (food browns as it cooks)

3.3. Production of a gas (bubbles during a reaction)Production of a gas (bubbles during a reaction)

4.4. Formation of precipitateFormation of precipitate Solid that forms and settles out of a liquid (soap scum)Solid that forms and settles out of a liquid (soap scum)

EVEN IF you observe one of the 4 clues, does EVEN IF you observe one of the 4 clues, does not give certainty of chemical changenot give certainty of chemical change

Ex: boiling water is a physical changeEx: boiling water is a physical change

Conservation of Mass 2.4Conservation of Mass 2.4Law of Conservation of Mass - any Law of Conservation of Mass - any

physical or chemical change mass if physical or chemical change mass if neither created nor destroyedneither created nor destroyedEasier to observe in a closed containerEasier to observe in a closed containerMatter can be released into the air or Matter can be released into the air or

surroundingssurroundings