Chem Quiz #1

Front 1

chemistry

Back 1

the science of the composition and structure of materials & the changes that materials undergo

Front 2

composition

Back 2

element, compound, mixture, ions

Front 3

structure

Back 3

covalent bonds, ionic bonds, molecular structure, crystal lattice

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why is chem so important?

Back 4

its a central science to help us understand bio processes, cure illnesses, etc

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central principle of chem

Back 5

materials around us are composed of exceedingly small particles (atoms) & the precise arrangement of these atoms into molecules

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polyatomic ion

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more than 1 atom covalently bonded to other atoms w/ a net charge

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experiment

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observation of natural phenomena carried out in a controlled manner such that the results can be duplicated & such that rational conclusions can be drawn

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law

Back 8

concise statement or mathematical equation about a fundamental relationship (can be statement or equation) or regularity of nature
ex: law of conservation

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hypothesis

Back 9

tentative explanation of some regularity of nature; meant to be tested

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theory

Back 10

tested explanation of basic natural phenomena

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what's the most important part of an experiment

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the scientist

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solid

Back 12

rigid, relatively incompressible, fixed shape & volume, relatively strong intermolecular forces

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liquid

Back 13

fluid, relatively incompressible, no shape but fixed volume, relatively moderate intermolecular forces

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gas

Back 14

fluid, easily compressible bc of all the space, negligible intermolecular forces, no shape & no fixed volume

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change of phase

Back 15

change of substance state from 1 state to another

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solid to liquid

Back 16

melting

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liquid to gas

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boiling

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gas to liquid

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condensation

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liquid to solid

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freezing

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solid to gas

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sublimation

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gas to solid

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deposition

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liquefaction

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substance usually a gas converted to a liquid

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physical property

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can reverse; can be observed w/o changing chem identity (physical state, color, etc)
ex: melting, dissolving, boiling, etc

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physical change

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change in form of matter but not in chem identity

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substance

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kind of matter that cant be separated into other kinds of matter by any physical means

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element

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substance that cant be decomposed by any chem rxn into more simple substances

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compound

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substance composed of 2 or more elements chemically combined

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chem change/rxn

Back 28

change in structure; atoms are rearranged; electrons being shared/transferred; 1 or more forms of matter are converted to diff. kinds of matter

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chem property

Back 29

characteristics of a material related to change in its identity
ex: iron reacts w/ oxygen to produce rust

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mixture

Back 30

material that can be separated by physical means into 2 or more substances; variable composition
ex: salt water

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heterogeneous mixture

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consists of physically distinct parts w/ diff properties
ex: salt & sugar

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homogenous mixture (solution)

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uniform in its properties throughout given samples
ex: air

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phase

Back 33

one of several diff homongenous materials present in a portion of matter under study
ex: a homogenous mix of salt & sugar is composed of 2 diff phases: 1 salt & 1 sugar

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synthesize

Back 34

build large molecules from smaller ones

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DNA

Back 35

2 intertwined molecule chains w/ 4 diff types of molecule pieces

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vapor

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the gaseous state of any kind of matter that normally exists as a solid or liquid

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distillation

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one way to separate mixtures
ex: sodium chloride & water components

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t/f no matter what its source, a substance always has the same characteristic properties

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true

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law of definite proportions/ constant compostion

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a pure compound, whatever its source, always contains definite or constant proportions of the elements by mass
ex: 1.0000 g of sodium chloride always has 0.3934 g of sodium & 0.6066 g of chlorine

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mass

Back 40

quantity of matter in a material

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matter

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occupies space & can be perceived by our senses

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law of conservation of mass

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total mass remains constant during chem rxn

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sublimation

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a purification technique

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molecular compound

Back 44

formed from covalent bonds

Front 45

intermolecular forces

Back 45

interactions btwn molecules

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electronegativity

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the tendency of an atom to attract electrons in the formation of an ionic bond

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dipole dipole interactions

Back 47

alignment of the negative end of 1 molecule w/ the positive end of another molecule

Front 48

dipole moment

Back 48

quantitive measure of the degree of charge separation in a molecule
-any molecule that has a net separation of charge has a dipole moment

Front 49

london (dispersion) forces

Back 49

weak attractive forces btwn molecules resulting from the small, instantaneous dipoles that occur b/c of the varying positions of the electrons during their motion about the nuclei