Honors ChemistryHonors Chemistry Chapter 2 Chapter 2

Matter and ChangeMatter and Change

• Matter – anything that has mass and takes up space

• Mass- amount of matter an object contains

• Materials – differ in type of matter they are composed of

The Properties of MatterThe Properties of Matter

• Extensive properties – depend on the amount of matter that is present– Example – volume, mass, amount of energy

in the substance

• Intensive properties – do not depend on the amount of matter that is present– Example – melting point, boiling point, density

• Substance – matter that is uniform and Substance – matter that is uniform and has a definite compositionhas a definite composition– All samples of an identical substance have All samples of an identical substance have

the identical physical and chemical the identical physical and chemical propertiesproperties

Physical property Physical property – quality or condition of a – quality or condition of a substance that can be observed or measured substance that can be observed or measured without changing the substance’s without changing the substance’s compositioncomposition

When a substance undergoes a physical change, its physical appearance changes.

Ice melts: a solid is converted into a liquid.

Physical changes DO NOT result in a change of composition.

Properties of Matter

Examples of Physical Properties

Color Odor Hardness Density Solubility Melting point, boiling point, freezing

point Physical state – solid, liquid, gas

• Page 40 Table 2.1 Physical properties of some substances

States of matterStates of matter

• Solid (s)

• Liquid (l)

• Gas (g)• Plasma – we don’t deal with

States of Matter

Matter can be a gas, a liquid, or a solid.

Gases have no fixed shape or volume.

Gases can be compressed to form liquids.

Liquids have no shape, but they do have a volume.

Solids are rigid and have a definite shape and volume.

Classification of MatterClassification of Matter

Gas and vapor not the same

Gas – normally exists that way at room temperature

Vapor – gas state of a substance that is normally a liquid or solid at room temperature

Physical change

• A change which alters a material without changing its composition

• Cutting, grinding, melting, boiling, freezing, dissolving

• Physical and Chemical Changes

Mixtures

Physical blend of two or more substances

Composition can vary

2 types:

Heterogeneous

Homogeneous

Heterogeneous Mixture

Not uniform in composition

Has 2 or more phases

Phase – any part of a system with uniform composition and properties

Dirt, salad, paper, rocky road ice cream

Homogeneous MixtureHomogeneous Mixture

Has a completely uniform Has a completely uniform composition composition

All components are evenly All components are evenly distributeddistributed

Consists of a single phaseConsists of a single phaseCalled a SOLUTIONCalled a SOLUTION

Solution – what do you think of?Solution – what do you think of?

• Can be gas, liquid, or solid!!!!!

Separating mixturesSeparating mixtures

Use PHYSICAL methodsUse PHYSICAL methods Magnet, sifting, Magnet, sifting, Liquid mixtures – distillation Liquid mixtures – distillation

Page 47Page 47

Organic distillation

Distillation

Substances

Can be elements or compounds

Element – definitionCompound – 2 or more elements that

have been CHEMICALLY combined.Can only be separated by CHEMICAL

means

• Sugar + heat carbon + water

• Water + electric current hydrogen +

oxygen

Properties of compoundsProperties of compounds

MUCH DIFFERENT THAN THE MUCH DIFFERENT THAN THE PROPERTIES OF THE ELEMENTS PROPERTIES OF THE ELEMENTS FROM WHICH THEY ARE FROM WHICH THEY ARE COMPOSED!!!!!COMPOSED!!!!!

NaClNaCl

Matter

substance mixture

element compound heterogeneous homogeneous

Flow chart – Pg. 50Flow chart – Pg. 50

Elements Elements represented by represented by symbolssymbols

Compounds Compounds represented by represented by formulasformulas

Pg. 52 Table 2.2Pg. 52 Table 2.2

Chemical ChangeChemical Change

A change that produces matter with A change that produces matter with a a different composition different composition than the than the original matteroriginal matter

Properties of MatterWhen a substance changes its composition, it undergoes a chemical change:

When pure hydrogen and pure oxygen react completely, they form pure water.

Is iron transforming into rust a Is iron transforming into rust a physical or chemical changephysical or chemical change

A.A. PhysicalPhysical

B.B. ChemicalChemical

Does the substance change composition or just change appearance?

The color of sulfur is The color of sulfur is yellow..yellow..

A.A. Physical Physical

B.B. ChemicalChemical

Does the substance change composition or just change appearance?

Dynamite explodes to form a Dynamite explodes to form a mixture of gasesmixture of gases

A.A. PhysicalPhysical

B.B. ChemicalChemical

Does the substance change composition or just change appearance?

Aluminum melts at 933 K Aluminum melts at 933 K

A.A. PhysicalPhysical

B.B. ChemicalChemical

Does the substance change composition or just change appearance?

Plants use COPlants use CO2 2 to make sugar to make sugar

A.A. PhysicalPhysical

B.B. ChemicalChemical

Does the substance change composition or just change appearance?

Chemical Reactions

One or more substances change into new substances

REACTANT(S) PRODUCT(S)

means “change into”, “produce”, “yields”

Chemical Property• The ability of a substance to

undergo chemical reactions and to form new substances

• Rusting, burning, fermenting, exploding, rotting, decomposing

• Iron and sulfur example

Indications that a chemical reaction has occurred

•Energy released or absorbed•Color change•Odor released•Production of a gas• Irreversibility•Production of light

Law of Conservation of Mass

• During any chemical reaction, the mass of the products is always equal to the mass of the reactants.