Chapter 1 Matter, Measurement And Problem Solving

Chemistry: A Molecular Approach, 1st Ed.Nivaldo TroChapter 1Matter,Measurement,and ProblemSolvingRoy KennedyMassachusetts Bay Community CollegeWellesley Hills, MA2008, Prentice Hall

Composition of MatterAtoms and MoleculesScientific Method

Structure Determines Properties the properties of matter are determined by the atomsand molecules that compose it1.2.3.4.carbon monoxidecomposed of one carbon atomand one oxygen atomcolorless, odorless gasburns with a blue flamebinds to hemoglobinTro, Chemistry: A Molecular Approach1.2.3.4.carbon dioxidecomposed of one carbon atomand two oxygen atomscolorless, odorless gasincombustibledoes not bind to hemoglobin3

Atoms and Molecules atoms are submicroscopic particles are the fundamental building blocks of all matter molecules two or more atoms attached together attachments are called bonds attachments come in different strengths molecules come in different shapes and patterns Chemistry is the science that seeks to understand thebehavior of matter by studying the behavior of atomsand moleculesTro, Chemistry: A Molecular Approach4

The Scientific Approach to Knowledge philosophers try to understand the universe byreasoning and thinking about “ideal” behavior scientists try to understand the universe throughempirical knowledge gained through observationand experimentTro, Chemistry: A Molecular Approach5

From Observation to Understanding Hypothesis – a tentative interpretation or explanationfor an observation falsifiable – confirmed or refuted by other observations tested by experiments – validated or invalidated when similar observations are consistently made, it canlead to a Scientific Law a statement of a behavior that is always observed summarizes past observations and predicts future ones Law of Conservation of MassTro, Chemistry: A Molecular Approach6

From Specific to General Understanding a hypothesis is a potential explanation for asingle or small number of observations a theory is a general explanation for themanifestation and behavior of all nature models pinnacle of scientific knowledge validated or invalidated by experiment andobservationTro, Chemistry: A Molecular Approach7

a test of ahypothesisor theoryScientific Methodthe careful notingand recording ofnatural phenomenaTro, Chemistry: A Molecular Approacha tentative explanation of asingle or small number ofnatural phenomenaa general explanationof natural phenomenaa generally observednatural phenomenon8

Classification of MatterStates of MatterPhysical and Chemical PropertiesPhysical and Chemical Changes

Classification of Matter matter is anything that has mass and occupiesspace we can classify matter based on whether it’ssolid, liquid, or gasTro, Chemistry: A Molecular Approach10

Classifying Matterby Physical State matter can be classified as solid, liquid, or gasbased on the characteristics it dNoNoLiquidIndef.FixedNoYesGasIndef.Indef.YesYes Fixed keeps shape when placed in a container Indefinite takes the shape of the containerTro, Chemistry: A Molecular Approach11

Solids the particles in a solid are packed closetogether and are fixed in position though they may vibrate the close packing of the particles results in solids being incompressiblethe inability of the particles to movearound results in solids retaining theirshape and volume when placed in a newcontainer, and prevents the particlesfrom flowingTro, Chemistry: A Molecular Approach12

Crystalline Solids some solids have theirparticles arranged in anorderly geometric pattern –we call these crystallinesolids salt and diamondsTro, Chemistry: A Molecular Approach13

Amorphous Solids some solids have theirparticles randomlydistributed without anylong-range pattern – we callthese amorphous solids plastic glass charcoalTro, Chemistry: A Molecular Approach14

Liquids the particles in a liquid are closely packed, but they have some ability tomove aroundthe close packing results in liquidsbeing incompressiblebut the ability of the particles tomove allows liquids to take the shapeof their container and to flow –however, they don’t have enoughfreedom to escape and expand to fillthe containerTro, Chemistry: A Molecular Approach15

Gases in the gas state, the particles have complete freedom fromeach otherthe particles are constantlyflying around, bumping intoeach other and the containerin the gas state, there is a lot ofempty space between theparticles on averageTro, Chemistry: A Molecular Approach16

Gases because there is a lot ofempty space, the particlescan be squeezed closertogether – therefore gasesare compressible because the particles are notheld in close contact and aremoving freely, gases expandto fill and take the shape oftheir container, and will flowTro, Chemistry: A Molecular Approach17

Classification of Matterby Composition matter whose composition does not change from onesample to another is called a pure substance made of a single type of atom or molecule because composition is always the same, all samples havethe same characteristics matter whose composition may vary from one sampleto another is called a mixture two or more types of atoms or molecules combined invariable proportions because composition varies, samples have the differentcharacteristicsTro, Chemistry: A Molecular Approach18

Classification of Matterby Composition1) made of one type ofparticle2) all samples show thesame intensivepropertiesTro, Chemistry: A Molecular Approach1) made of multipletypes of particles2) samples may showdifferent intensiveproperties19

Classification of Pure Substances substances that cannot be broken down into simplersubstances by chemical reactions are called elements basic building blocks of matter composed of single type of atom though those atoms may or may not be combined into molecules substances that can be decomposed are called compounds chemical combinations of elements composed of molecules that contain two or more different kindsof atoms all molecules of a compound are identical, so all samples of acompound behave the same way most natural pure substances are compoundsTro, Chemistry: A Molecular Approach20

Classification of Pure Substances1) made of onetype of atom(some elementsfound as multiatommolecules innature)2) combinetogether tomakecompounds1) made of onetype ofmolecule, orarray of ions2) moleculescontain 2 ormore differentkinds of atoms21

Classification of Mixtures homogeneous mixture that has uniformcomposition throughout every piece of a sample has identical characteristics, thoughanother sample with the same components may havedifferent characteristics atoms or molecules mixed uniformly heterogeneous mixture that does not have uniformcomposition throughout contains regions within the sample with differentcharacteristics atoms or molecules not mixed uniformlyTro, Chemistry: A Molecular Approach22

Classification of Mixtures1) made ofmultiplesubstances,whosepresence canbe seen2) portions of asample havedifferentcompositionand properties1) made ofmultiplesubstances, butappears to beone substance2) all portions ofa sample havethe samecompositionand properties23

Separation of Mixtures separate mixtures based on differentphysical properties of the components Physical changeDifferent Physical PropertyTechniqueBoiling PointDistillationState of Matter (solid/liquid/gas)FiltrationAdherence to a entrifugation &DecantingTro, Chemistry: A Molecular Approach24

Distillation25

Filtration26

Changes in Matter changes t

Solids the particles in a solid are packed close together and are fixed in position though they may vibrate the close packing of the particles results in solids being incompressible the inability of the particles to move around results in solids retaining their shape and volume when placed in a new container, and prevents the particles