PROPERTIES OF MATTER

OBJECTIVES Identify properties of amtter as extensive or intensive

Define physical property and list several common physical properties of substances

Differentiate among three states of matter

Describe a physical change

KEY CONCEPTS How can properties used to describe matter be classified?*

Why do all samples of substance have the same intensive properties?*

What are three states of matter?*

How can physical changes be classified?*

DESCRIBING MATTER Properties used to describe matter can be classified as extensive or intensive*

DESCRIBING MATTER 2 properties used to describe matter:Extensive propertyIntensive property

EXTENSIVE PROPERTY Depends on the amount of matter in a sample

Common extensive properties:Mass – measure of the amount of matter the object contains (grams)

Volume – measure of space occupied by the object

INTENSIVE PROPERTY Depends on the type of matter in a sample

Common intensive properties:Density – mass per unit volume

Melting point and boiling point – temp at which substance melts or boils

Magnetization

IDENTIFYING SUBSTANCE Substance – matter that has a uniform and definite composition

Every sample of a given substance has identical properties because each sample is the same

PROPERTIES Words that describe matter 2 types of identifying properties:Physical propertyChemical property

PHYSICAL PROPERTY Property that can be observed and measured without changing the material’s composition

Examples:ColorHardnessMelting pointBoiling point

CHEMICAL PROPERTY Property that can only be observed by changing the composition of the material

Examples:Ability to burnDecompositionFermentation

RECAP Properties describing matter

ExtensiveIntensive

Properties identifying matterPhysicalChemical

STATES OF MATTER*

SOLID Definite shape and volume Does not flow Does not take shape of container

Increase in temperature = small expansion

Does not compress

LIQUID Definite volume Take the shape of container Flows Increase in temperature = small expansion

Does not compress

GAS No definite volume No definite shape – will take shape of container

Flows Increase in temperature results in large expansion

Can be compressed

GAS (VAPOR) Substance that is currently a gas but normally is a liquid or solid at room temperatureOccurs with an increase in temperature

“Water vapor”

PLASMA 4th state of matter Formed at high temperatures Ionized phase of matter as found in the sun

COPPER PHASES - SOLID

COPPER PHASES - LIQUID

COPPER PHASE – VAPOR (GAS)

PHYSICAL VS. CHEMICAL CHANGE Physical change – changes the visible appearance, without changing the composition of the materialBoil, melt, cut, bend, splitIs boiled water still water?

Can be reversible or irreversible*

PHYSICAL VS. CHEMICAL CHANGE Chemical change – change where a new form of matter is formedRust, burn, decompose

Irreversible

ASSESSMENT In what way are liquids and gases alike? In what way are liquids and solids different?

Why do all samples of a given substance have the same intensive properties?

MIXTURES

OBJECTIVES Categorize a sample of matter as a substance or a mixture

Distinguish between homogeneous and heterogeneous samples of matter

Describe two ways that components of mixtures can be separated

KEY CONCEPTS How can mixtures be classified?*

How can mixtures be separated?*

MIXTURES Mixture – made of 2 or more different components

Classified as either:*Heterogeneous mixtureHomogeneous mixture

HETEROGENEOUS MIXTURE Mixture is not uniform in composition

Examples:Chocolate chip cookieSoil

HOMOGENEOUS MIXTURE Mixture with same composition throughout

AKA “solution” Examples:

Kool-aidSalt water

SOLUTIONS Mixed molecule by molecule thus too small to see different parts but no definite composition

Can occur between any state of matterGas in gasGas in liquidSolid in liquid

PHASE Any part of a sample with uniform composition of properties

How many phases in a homogeneous mixture?

How many phases in a heterogeneous mixture?

SEPARATING MIXTURES Some mixtures can be separated easily by physical meansCan you name some?

Differences in physical properties can be used to separate mixtures*

FILTRATION Separates a solid from the liquid in a heterogeneous mixture

PAPER CHROMATOGRAPHY Separate components of dyes such as ink

DISTILLATION Takes advantage of different boiling points

Liquid is boiled to produce vapor that is then condensed to liquid

ASSESSMENT Classify each of the following as homogeneous or heterogeneous:Food coloringIce cubes in waterMouthwashMashed, unpeeled potatoes

ASSESSMENT How are a substance and a solution similar? How are they different?

When would you use filtration to separate a mixture? When would you use distillation?

ELEMENTS AND COMPOUNDS

OBJECTIVE Explain the difference between an element and a compound

Distinguish between a substance and a mixture

Identify the chemical symbols of elements and name elements given their symbols

KEY CONCEPTS How are elements and compounds different?*

How can substances and mixtures be distinguished?*

What do chemists use to represent elements and compounds?*

ELEMENTS AND COMPOUNDS Substances are classified as either elements or compounds

ELEMENT Simplest kind of matter

Cannot be broken down any simpler and still have properties of that element

All one kind of atomElements are found on the periodic table

COMPOUNDS Substance that can be broken down only by chemical methods

Made of 2 or more elements chemically combined in fixed proportion

When broken down, the pieces have completely different properties than original compound

ELEMENT VS. COMPOUND Compounds can be broken down into similar substance by chemical means Elements cannot*

COMPOUND VS. MIXTURE

Compound Mixture Made of one kind

of materialMade of more than

one kind of material

Made by a chemical change

Made by a physical change

Definite composition

Variable composition

Water, salt, sugar, hydrogen, carbon

Seawater, sugar water, atmosphere

CHEMICAL CHANGE A change in which one or more substances are converted into different substance Heat and

light are evidence of chemical change

PROPERTIES OF COMPOUNDS Different properties than their

component elements Due to a CHEMICAL CHANGE, the

resulting compound has new and different properties:• Table sugar – carbon, hydrogen, oxygen

• Sodium chloride – sodium, chlorine

• Water – hydrogen, oxygen

CLASSIFICATION OF MATTER

SYMBOLS AND FORMULAS Currently 117 elements Elements have a 1 or 2 letter symbol and compounds have a formula*Thus formula is made up of more than one symbol Symbol can be the same – O2

SYMBOLS AND FORMULAS Elements first letter is always capitalized

If there is a second letter it is always lowercaseBBaCCa

ELEMENTS Start looking at element names Table B.7 on page R53

Page 52 Table 2.2 states a few

ASSESSMENT Classify each of these samples of matter as an element, a compound, or a mixture:Table sugarCough syrupTap waterNitrogen

ASSESSMENT What elements make up the pain reliever acetaminophen, chemical formula C8H9O2N?

Which element is present in the greatest proportion by number of particles?

CHEMICAL REACTIONS

OBJECTIVES Describe what happens during a chemical change

Identify 4 possible clues that a chemical change has taken place

Apply the law of conservation of mass to chemical reactions

KEY CONCEPTS What always happens duringa chemical change?*

What are four possible clues that a chemical change has taken place?*

How are the mass of the reactants and the mass of the products of a chemical reaction related?*

CHEMICAL PROPERTY Ability of substance to undergo a specific chemical changeIron + oxygen = rustRust is chemical property of iron

Once again, during a chemical change the composition of matter always changes*

CHEMICAL REACTION One or more substances changes into a new substance2H2 + O2 2H2O

Reactants – what you start with

Products – what you makeHave different properties than reactants

RECOGNIZING CHEMICAL CHANGES1. Energy – either absorbed or

released as heat2. Color change3. Gas production – bubbling,

fizzing, smoke or odor change4. Precipitate formation – solid

that separates from solution (won’t dissolve)

5. Irreversibility***

CHECK POINT

What energy transfer takes place when food cooks?

CONSERVATION OF MASS During a chemical reactionmass of products = mass of reactants*

All mass is accounted for:Burning of wood results in products that appear to have less mass as ashes; where is the rest?

ASSESSMENT What is the different between physical changes and chemical changes?

ASSESSMENT Classify the following changes as physical or chemical changesWater boilsMilk turns sourSalt dissolves in waterA metal rusts

ASSESSMENT Hydrogen and oxygen react chemically to form water. How much water would form if 4.8 grams of hydrogen reacted with 38.4 grams of oxygen?