Chapters 1-4

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Terms in this set (71)
qualitative dataobtained through observations that describe the color, smell, shape, or another physical characteristic that is related to the 5 sensesquantitative dataobtained from numerical observations that describe how much, how little, how big, or how fasthypothesistentative explanation for what's been observed; if-then statement; the steps in a scientific method are repeated until a hypothesis is provenexperimentset of controlled observations that test the hypothesisvariablea quantity or condition that can have more than 1 valueindependent variablevariable you plan to changedependent variablevariable that changes in value in response to a change in the independent variablecontrolstandard for comparison in the experimentconclusionjudgement based on the information obtained from the experimenttheoryan explanation that has been repeatedly supported by many experimentsscientific lawa relationship in nature that is supported by many experiments and no exceptions to these relationships are foundsyntheticsomething that is human-made and does not necessarily occur in naturepure researchresearch to gain knowledge for the sake of knowledgeapplied researchresearch undertaken to solve a problemchance discoverieswhen scientists obtain results that are far different from expectedstates of matter1. solid 2. liquid 3. gassolidsa form of matter that have their own definite shape and volumeliquidsa form of matter that have a definite volume but take the shape of the containergashas no definite shape or volumevaporgaseous state of a substancephysical propertya characteristic that can be observed or measured without changing the sample compositionextensive propertiesdependent on the amount of substance present, such as mass, length, or volumeintensive propertiesindependent of the amount of substance present, such as densitychemical propertyability of a substance to combine with or change into one or more other substances; can change w/ specific environmental conditions, such as temperature and pressurephysical changechange that alters a substance without changing its compositionphase changea transition of matter from one state to anotherexamples of phase changesboiling freezing melting condensingchemical changechange that involves one or more substances turning into new substancesexamples of chemical changes1. decomposing 2. rusting 3. exploding 4. burning 5. oxidizinglaw of conservation of massmass is neither created nor destroyed in a chemical reaction; it is conservedmixturea combination of two or more pure substances in which each pure substance retains it's individual chemical propertyhomogenus mixturea mixture where the composition is constant throughout; also known as solutionheterogenus mixturea mixture where the individual substances remain distincttypes of solution systems1. gas-gas 2. gas-liquid 3. liquid-gas 4. liquid-liquid 5. solid-liquid 6. solid-solidtypes of separation techniques1. filtration 2. distillation 3. crystallizationfiltrationseparation technique that uses a porous barrier to separate a solid from a liquid (heterogenous)distillationseparation technique for homogeneous mixture that is based on the differences in boiling points of substancescrystallizationseparation technique for homogeneous mixture that results in the in forming of pure solid particles form a solution containing the dissolved substancessublimationthe process of a solid changing directly to a gas, which can be used to separate mixtures of solids when are sublimates and the other does notchromatographya technique that separates the components of a mixture on the basis of tendency of each to travel across the surface of another materialelementpure substance that cannot be separated into simpler substances by any meansperiodic tableorganizes elements into grid of rows called periods and columns called groupscompoundmade up of 2 or more elements combined chemicallyeletrolysisusing electricity to break compounds apartlaw of definite proportionsa compound is always composed of the same elements in the same proportion by mass (no matter how large or small)percent by massmass of element/mass of compoundlaw of multiple proportionswhen different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in whole number ratiosconservation of massmass reactants = mass productdalton's atomic theoryexplains conservation of mass in reaction as a result of the combination, separation or rearrangement of atomsatomthe smallest particle of an element that retains the properties of the elementcathode rayray of radiation that travels from the cathode to the anode, when on electric change is applied (carry negative charge)electronsparticles with a negative chargefundamental subatomic particles1. electron 2. proton 3. neutronatomic numberthe number of protons in the nucleus of an atom; an identifierisotopesatoms with the same number of protons but different numbers of neutronsmass numberthe sum of protons and neutrons in the nucleusatomic mass unit1/12th the mass of a carbon-12 atomatomic massthe weighted average mass of the isotopes of the elementpositive ioncat-ionnegative ionan-ionamu formula steps:Atomic Mass 1 x Percent 1= AMU 1 Atomic Mass 2 x Percent 2 = AMU 2 AMU 1+ AMU 2 = Average AMU