Chapter 1Lecture OutlineChem 120Chemistry: study of matter and changes matter undergoesCHEMISTRY: MATTER AND MEASUREMENT1. Chemistry is the study of …Composition StructurePropertiesMatter = anything that occupies space and has massAtoms = smallest building blocks of matterMolecules = two or more atoms combinedMATTER CLASSIFICATIONS:Substance = uniform composition, stays the sameElement = cannot be decomposed into simpler substances that are made of the same kind of atomCompound = composed of two or more different elementsMixture = combination of two or more substancesHomogeneous Mixture = uniform throughout (solution, alloys)1Heterogeneous Mixture = different composition throughout (sand and water)Types of PropertiesPhysical Properties are displayed by a sample of matter without changing identity or composition of a substanceExamples boiling point, melting point, densityChemical Properties – are displayed by a sample of matter as it undergoes a change in Composition a substance is changed into another substanceExamples: flammability, corrosiveness, reactivity with acidInstensive Properties: independentbof amount of substance present- Density, boiling pointExtensive Properties: depend on amount of substance- Mass, volumePhysical Changes - changes in matter that do not change the composition of a substance.Chemical Change - the matter undergoes a change in composition, a new substance.2Separation of Mixtures• Distillation uses differences in the boiling points of substances to separate a homogeneous mixture into its components.• In filtration solid substances are separated from liquids and solutions.• Chromatography is a technique that separates substances on the basis of differences in solubility in a solvent.1.4 SCIENTIFIC MEASUREMENTSMetric System – powers of 10Units larger or smaller than the base unit are expressed by the use of a LENGTH base unit: ________________________1 meter = ________________ inchesPrefix Length unitEquivalent to: 1 m has3Kilo (k)deci (d)centimillimicronanoVOLUME base unit: ______________________1 Liter = _________ quartsMASS base unit: ______________________1 gram = _________ oz1 oz = 1 kg = ________ lbsTIME base unit: ______________________4The derived unit of volume1 Liter = 1 dm31 mL = 1 ______cubic centimeter5Mass – quantity of matter in an objectWeight – force a mass experiences under the pull of gravity *dependent on locationTEMPERATURE: is a measure of the average kinetic energy of the particles in a sample.Temperature scales:Fahrenheit: 1.8(C) + 32Celcius: (F-32)/1.8 = K-273Kelvin : C+ 273 61.5 PRECISION AND ACCURACY IN MEASUREMENTSPrecision = proximity of several measurements to each otherAccuracy = proximity of a measurement to the true value of the quanititySIGNIFICANT FIGURES (sig figs)We do not want to claim more precision in our work than we actually obtained.Significant figure convention is observed so that the answer we report represents the precision of our measurementsReport all known digits, plus ____________________________________________consider 4 measurements of a stick: 1.76 m, 1.74 m, 1.76 m, 1.75 m, average = 1.7525 meters?certain of ____________, some uncertainty in ______________, no certainty in __________- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --SIGNIFICANT FIGURE RULES:1. Any non-zero digit is significant2. The ZERO- between two sig fig is sig , 303 4.02- to left of first sig fig is not sig , 0.123, 0.0033- to right of sig fig and right of decimal is sig. , 0.0044003. Zero to right of sig fig but no decimal is undetermined 400 ??report in scientific notation format 4.0 x 102 (4.0E2)50.00303170.00230.040502.00*DEFINED AND COUNTING NUMBERS do not have uncertainty. 14 people 1000m = 1 kmThese numbers are exact.*ROUNDING:look at left-most non-significant figureif 5 or greater, round upif 4 or less, no changeSig Figs in CalculationsA calculated quantity can be no more _______________ than the data used in the calculation.IN MULTIPLICATION AND DIVISION: The answer has no more sig figs than the factor with the FEWEST sig figs.Examples:1002 / 2.0 =111 x 3 =IN ADDITION AND SUBTRACTION: The answer has no more digits past the decimal point thanthe factor with the FEWEST digits past the decimal point.Examples:1102 + 24.11 =111.11 - 11.1 =- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --81.6 Unit-Conversion Method = Dimensional AnalysisALWAYS use a number with its unit.conversion factor: $used to convert the data from one set of units to another $is derived from a relationship between units, usually an equal statement1 m = 100 cmput in fraction formof the two forms, we use the factor that cancels the unit in the measurement and produces the desired unit in the answerExample: A child's foot is 6.5 inches long. How long is this in cm?Example: Suppose milk costs $2.54/gallon in Knoxville and we wish to know its cost in Canadian dollars/liter.($0.71 = c1.00, 1.000 liter = 1.057 qt)Squaring and cubing units:How many gallons are there in one cubic foot?2.54 cm = 1 in, 3.78 L = 1 galDENSITY = _________________________________________________________________• physical property of matter• use as conversion factor9Examples:A 125 mL volume of carbon tetrachloride has a mass of 192.5 g. What is the density of the liquid?What mass of CCl4 is contained in a 355 mL flask? (d = s.a.)What is the volume of 3.750 lb of carbon tetrachloride?2.20 lb = 1 kg, d = 1.54