Properties of MatterProperties of MatterProperties and ChangesProperties and Changes

Physical PropertiesPhysical Properties SubstanceSubstance – matter that has a uniform – matter that has a uniform

and unchanging composition (pure and unchanging composition (pure substance)substance) Example: salt – NaCl, water – HExample: salt – NaCl, water – H22O O Salt water – not pure, changes w/location!Salt water – not pure, changes w/location!

Physical propertiesPhysical properties – characteristics that – characteristics that can be observed or measured without can be observed or measured without changing the composition (includes changing the composition (includes pure substances)pure substances) viscosityviscosity hardnesshardness densitydensity conductivityconductivity melting pointmelting point colorcolor malleabilitymalleability boiling pointboiling point odorodor

Types of Physical PropertiesTypes of Physical Properties(Activity)(Activity)

1.1. Extensive propertiesExtensive properties – dependent on – dependent on amount presentamount present

MassMass weightweight lengthlength volumevolume

2.2. Intensive propertiesIntensive properties – independent of – independent of amount present; used to identify a amount present; used to identify a substancesubstance

DensityDensity lusterluster conductivityconductivity ColorColor malleabilitymalleability hardnesshardness OdorOdor ductilityductility melting/freezing/boiling pointmelting/freezing/boiling point

Using Physical PropertiesUsing Physical Properties Identification of a material – crucial Identification of a material – crucial

in solving crimesin solving crimes Choose a material for a specific Choose a material for a specific

purpose - shoelacespurpose - shoelaces Separation of the substanceSeparation of the substance

magnetic propertiesmagnetic properties crystallizationcrystallization filtrationfiltration chromatographychromatography distillationdistillation

Recognizing Physical ChangesRecognizing Physical Changes Some of the properties of a material Some of the properties of a material

change, but the substances in the change, but the substances in the material remain the same – some are material remain the same – some are reversiblereversible heating butterheating butter crumpling papercrumpling paper slicing a tomatoslicing a tomato wrinkly shirt/ironwrinkly shirt/iron hair braidinghair braiding peeling orangespeeling oranges

Chemical PropertiesChemical Properties Chemical propertiesChemical properties – the ability of a – the ability of a

substance to combine with or change substance to combine with or change into another substanceinto another substance Iron + OIron + O22 -> Rust (FeO -> Rust (FeO22)) COCO22 + H + H220 -> C0 -> C66HH1212OO6 6 + O+ O22

EVERY SUBSTANCE HAS A EVERY SUBSTANCE HAS A UNIQUE SET OF PHYSICAL AND UNIQUE SET OF PHYSICAL AND CHEMICAL PROPERTIESCHEMICAL PROPERTIES

Observing Chemical PropertiesObserving Chemical Properties Flammability – ability to burn in the Flammability – ability to burn in the

presence of oxygenpresence of oxygen fuelsfuels fabricfabric fire startersfire starters flame-resistanceflame-resistance

Reactivity – how readily a substance Reactivity – how readily a substance combines chemically with other combines chemically with other substancessubstances Oxygen – high, rustOxygen – high, rust Nitrogen - lowNitrogen - low

Recognizing Chemical ChangesRecognizing Chemical Changes Evidence of chemical changes Evidence of chemical changes

include:include: change in colorchange in color – leaves on trees, – leaves on trees,

banana peel, copper, silverbanana peel, copper, silver Production of gasProduction of gas – vinegar and – vinegar and

baking soda, cake bakingbaking soda, cake baking Formation of a precipitateFormation of a precipitate – acid + – acid +

milk (protein goes through chemical milk (protein goes through chemical change), cottage cheesechange), cottage cheese

States of MatterStates of Matter Materials can be classified as solids, Materials can be classified as solids,

liquids, gases, or plasma based on liquids, gases, or plasma based on whether their shapes and volumes are whether their shapes and volumes are definite or variable (plasma only definite or variable (plasma only occurs naturally in the form as occurs naturally in the form as lightning bolts)lightning bolts)

Shape and volume are clues to how Shape and volume are clues to how the particles within a material are the particles within a material are arrangedarranged

PlasmaPlasma Free electrons are released at a very Free electrons are released at a very

high temperaturehigh temperature lightninglightning sunsun neon signsneon signs firefire

SolidsSolids Definite shape and volumeDefinite shape and volume Atoms are packed close together and Atoms are packed close together and

have an orderly arrangement of particleshave an orderly arrangement of particles Changing the container doesn’t change Changing the container doesn’t change

the shape or volume of a solidthe shape or volume of a solid Examples: pencil, cafeteria tray, book, Examples: pencil, cafeteria tray, book,

quarterquarter Can you change the shape or volume of Can you change the shape or volume of

an object that is solid?an object that is solid?

LiquidsLiquids Definite volume and take the shape of Definite volume and take the shape of

its containerits container Can be poured, will take on a new Can be poured, will take on a new

shapeshape Atoms are close together, but their Atoms are close together, but their

arrangement is more random than arrangement is more random than those of a solidthose of a solid

Examples: juice, water, mercury, honeyExamples: juice, water, mercury, honey

GasesGases Does not have a definite shape nor a definite Does not have a definite shape nor a definite

volumevolume Takes the shape and volume of its containerTakes the shape and volume of its container Atoms are not arranged in a regular pattern Atoms are not arranged in a regular pattern

and can have a big space between themand can have a big space between them Vapor – refers to the gaseous form of a Vapor – refers to the gaseous form of a

substance that is a solid or liquid at room substance that is a solid or liquid at room temp.temp.

COMPRESSIBLECOMPRESSIBLE Examples: Air, helium, natural gasExamples: Air, helium, natural gas

How well did you listen?…How well did you listen?… A vapor and a gas are the same A vapor and a gas are the same

thing.thing. A liquid conforms to its container.A liquid conforms to its container. Particles of a gas are spaced closer Particles of a gas are spaced closer

together than particles of a liquid.together than particles of a liquid. A solid has a definite shape but A solid has a definite shape but

changeable volume.changeable volume.

Chemical EquationsChemical Equations A useful description of a chemical A useful description of a chemical

reaction tells you the substances reaction tells you the substances present before and after the reactionpresent before and after the reaction

ReactantsReactants undergo the change and undergo the change and the new substances that are formed the new substances that are formed are the are the productsproducts

Reactants -> ProductsReactants -> Products

Conservation of MassConservation of Mass The law of conservation of mass states The law of conservation of mass states

that mass is neither created nor that mass is neither created nor destroyeddestroyed

Piece of charcoal burns, gets smaller Piece of charcoal burns, gets smaller until it is a tiny pile of ash; charcoal is until it is a tiny pile of ash; charcoal is being converted into gaseous productsbeing converted into gaseous products

Mass of the products equal the mass of Mass of the products equal the mass of the charcoal and the oxygen reactedthe charcoal and the oxygen reacted

Conservation of MassConservation of Mass In order to show that mass is In order to show that mass is

conserved during a reaction, a conserved during a reaction, a chemical equation must be balanced chemical equation must be balanced using using coefficientscoefficients – numbers that – numbers that appear before the formulasappear before the formulas

Mass of reactants = Mass of productsMass of reactants = Mass of products 2 H2 H22 + O + O2 2 -> 2 H -> 2 H22OO 4 g + 32g -> 36 g4 g + 32g -> 36 g

Practice!Practice!

1. If 50 grams of sodium reacts with 1. If 50 grams of sodium reacts with chlorine to form 126 grams of salt. How chlorine to form 126 grams of salt. How many grams of chlorine reacted?many grams of chlorine reacted?

2. If 20 grams of aluminum reacts with 200 2. If 20 grams of aluminum reacts with 200 grams of bromide to form aluminum grams of bromide to form aluminum bromide, and no aluminum is left after bromide, and no aluminum is left after the reaction, but 23 grams of bromine the reaction, but 23 grams of bromine remained unreacted. How any grams of remained unreacted. How any grams of aluminum bromide were formed?aluminum bromide were formed?

Practice!Practice!

3. If 178.8 g of water is separated into 3. If 178.8 g of water is separated into hydrogen and oxygen gas, and the hydrogen and oxygen gas, and the hydrogen gas has a mass of 20.0 g. What hydrogen gas has a mass of 20.0 g. What is the mass of the oxygen gas produced?is the mass of the oxygen gas produced?

4. From a laboratory process, a student 4. From a laboratory process, a student collects 28.0 g of hydrogen and 224.0 g collects 28.0 g of hydrogen and 224.0 g of oxygen. How much water was of oxygen. How much water was originally involved in the process?originally involved in the process?

Practice!Practice!

5. A student carefully placed 23.0 g of sodium 5. A student carefully placed 23.0 g of sodium in a reactor with an excess quantity of in a reactor with an excess quantity of chlorine gas. When the reaction is chlorine gas. When the reaction is complete, the student obtained 58 grams of complete, the student obtained 58 grams of salt. How many grams of sodium reacted?salt. How many grams of sodium reacted?

6. A 10 gram sample of iron reacts with oxygen 6. A 10 gram sample of iron reacts with oxygen to form 18.2 grams of ferric oxide. How to form 18.2 grams of ferric oxide. How many grams of oxygen reacted?many grams of oxygen reacted?

Practice!Practice!7. 7. From a laboratory experiment designed to From a laboratory experiment designed to

separate water into hydrogen and oxygen separate water into hydrogen and oxygen gas, a student collected 10.0 g of hydrogen gas, a student collected 10.0 g of hydrogen and 79.4 g of oxygen. How much water was and 79.4 g of oxygen. How much water was initially involved in the process?initially involved in the process?

8. A student carefully placed 15.6 g of sodium 8. A student carefully placed 15.6 g of sodium in a reactor supplied with an excess quantity in a reactor supplied with an excess quantity of chlorine gas. When the reaction was of chlorine gas. When the reaction was complete, the student obtained 39.7 g of complete, the student obtained 39.7 g of sodium chloride. How many grams of sodium chloride. How many grams of chlorine gas reacted?chlorine gas reacted?

Practice!Practice!

9. In a flask, 10.3 g of aluminum reacted with 9. In a flask, 10.3 g of aluminum reacted with 100 g of liquid bromine to form aluminum 100 g of liquid bromine to form aluminum bromide. After the reaction, no aluminum bromide. After the reaction, no aluminum remained, and 8.5 grams of bromine remained, and 8.5 grams of bromine remained unreacted. How many grams of remained unreacted. How many grams of compound were formed?compound were formed?

10. A 10.0 g sample of magnesium reacts with 10. A 10.0 g sample of magnesium reacts with oxygen to form 16.6 g of magnesium oxide. oxygen to form 16.6 g of magnesium oxide. How many grams of oxygen reacted?How many grams of oxygen reacted?