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  • Edward Wen, PhDMatters and Measurement

  • Chemistry is about Everyday experienceWhy Cookies tastes different from Cookie Dough?Why Baking Powder or Baking Soda?Why using Aluminum Foil, not Paper Towel?What if the Temperature is set too high?Photo credit: itsnicethat.com*

  • Chapter OutlineClassification of mattersMeasurement, Metric system (SI)Scientific NotationSignificant figuresConversion factorDensity


  • *In Your RoomEverything you can see, touch, smell or taste in your room is made of matter.Chemists study the differences in matter and how that relates to the structure of matter.

  • *What is Matter?Matter: anything that occupies space and has massMatter is actually composed of a lot of tiny little pieces: Atoms and Molecules

  • *Atoms and MoleculesAtoms: the tiny particles that make up all matter. Helium gas (for blimp) is made up of Helium atoms.

    Molecules: In most substances, the atoms are joined together in units. Liquid water is made up of water molecules (2 Hydrogen atoms + 1 Oxygen atoms)

  • *Physical States of MattersMatter can be classified as solid, liquid or gas based on what properties it exhibits





















  • *Why different States of a Matter? Structure Determines Propertiesthe atoms or molecules have different structures in solids, liquid and gases

  • *SolidsParticles in a solid: packed close together and are fixed in positionthough they may vibrateIncompressibleretaining their shape and volumeUnable to flow

  • *LiquidsParticles are closely packed, but they have some ability to move around IncompressibleAble to flow, yet not to escape and expand to fill the container (not antigravity)

  • *GasesThe particles have complete freedom from each other (not sticky to each other)The particles are constantly flying around, bumping into each other and the containerThere is a lot of empty space between the particles (low density) Compressible Able to flow and Fill space (antigravity)

  • *Classifying Matter:

    Sugar, Copper, Coke, Gasoline/Water

  • *Classification of Matter

  • *Pure substanceMatter that is composed of only one kind of piece.Solid: Salt, Sugar, Dry ice, Copper, Diamond

    Liquid: Propane, distilled water (or Deionized water, DI water)

    Gas: Helium gas (GOODYEAR blimp)

  • *Classifying Pure Substances: Elements and CompoundsElements: Substances which can not be broken down into simpler substances by chemical reactions. (A,B)

    Compounds: Most substances are chemical combinations of elements. (C)Examples: Pure sugar, pure watercan be broken down into elementsProperties of the compound not related to the properties of the elements that compose it

  • *ElementsExample: Diamond (pure carbon), helium gas.116 known, 91 are found in natureothers are man-madeAbundance = percentage found in natureHydrogen: most abundant in the universe Oxygen: most abundant element (by mass) on earth and in the human bodySilicon: abundant on earth surface every sample of an element is made up of lots of identical atoms

  • *CompoundsComposed of elements in fixed percentageswater is 89% O & 11% Hbillions of known compoundsOrganic (sugar, glycerol) or inorganic (table salt)same elements can form more than one different compoundwater and hydrogen peroxide contain just hydrogen and oxygencarbohydrates all contain just C, H & O (sugar, starch, glucose)

  • *MixtureMatter that is composed of different kinds of pieces. Different samples may have the same pieces in different percentages. (D)

    Examples:Solid: Flour, Brass (Copper and Zinc), RockLiquid: Salt water, soda, GasolineGas: air

  • *Classification of MixturesHomogeneous = composition is uniform throughout appears to be one thingevery piece of a sample has identical properties, though another sample with the same components may have different propertiessolutions (homogeneous mixtures): Air; Tap waterHeterogeneous = matter that is non-uniform throughout contains regions with different properties than other regions: gasoline mixed with water; Italian salad dressing

  • *What is a Measurement?Quantitative observationcomparison to an agreed upon standard

    Every measurement has a number and a unit:77 Fahrenheit: Room temperature7.5 pounds: Average newborn body weight in the US:55 0.5 grams: amount of sugar in one can of Coca Cola

    UNIT: what standard you are comparing your object to the number tells youwhat multiple of the standard the object measuresthe uncertainty in the measurement ()

  • *Some Standard Units in the Metric System

    Quantity MeasuredName of UnitAbbreviationMassgramgLengthmetermVolumeliterLTimesecondssTemperatureKelvinK

  • *Related Units in the SI SystemAll units in the SI system are related to the standard unit by a power of 10 (exactly!)1 kg = 103 g 1 km = 103 m1 m = 102 cm

    The power of 10 is indicated by a prefixThe prefixes are always the same, regardless of the standard unit

  • *Prefixes Used to Modify Standard Unitkilo = 1000 times base unit = 1031 kg = 1000 g = 103 gdeci = 0.1 times the base unit = 10-11 dL = 0.1 L = 10-1 L; 1 L = 10 dLcenti = 0.01 times the base unit = 10-21 cm = 0.01 m = 10-2 m; 1 m = 100 cmmilli = 0.001 times the base unit = 10-31 mg = 0.001 g = 10-3 g; 1 g = 1000 mgmicro = 10-6 times the base unit1 m = 10-6 m; 106 m = 1 mnano = 10-9 times the base unit1 nL = 10-9L; 109 nL = 1 L

  • *Common Prefixes in the SI System

    PrefixSymbolDecimalEquivalentPower of 10mega-M1,000,000Base 106kilo-k 1,000Base 103deci-d 0.1Base 10-1centi-c 0.01Base 10-2milli-m 0.001Base 10-3micro-m or mc 0.000 001Base 10-6nano-n 0.000 000 001Base 10-9

  • *Standard Unit vs. PrefixesUsing meter as example:1 km = 1000 m = 103 m

    1 g = 10 dm= 100 cm = 102 cm= 1000 mm= 103 mm= 1,000,000 m= 106 m= 1,000,000,000 nm= 109 nm

  • *LengthTwo-dimensional distance an object covers

    SI unit: METER (abbreviation as m)About 3 inches longer than a yard1 m = 10-7 the distance from the North Pole to the Equator Commonly use centimeters (cm)1 m = 100 cm = 1.094 yard1 cm = 0.01 m = 10 mm1 inch = 2.54 cm (exactly)

  • *MassAmount of matter present in an object

    SI unit: kilogram (kg)about 2 lbs. 3 oz.

    Commonly measure mass in grams (g) or milligrams (mg)1 kg = 2.2046 pounds (1 lbs. = 0.45359)1 g = 1000 mg = 103 mg1 g = 0.001 kg = 10-3 kg

  • *VolumeAmount of three-dimensional space occupiedSI unit = cubic meter (m3)

    Commonly measure solid volume in cubic centimeters (cm3)1 m3 = 106 cm3 1 cm3 = 10-6 m3 = 0.000001 m3

    Commonly measure liquid or gas volume in milliliters (mL)1 gallon (gal) = 3.78 L = 3.78 103 mL1 L = 1 dm3 = 1000 mL = 103 mL 1 mL = 1 cm3 = 1 cc (cubic centimeter)

  • *Common Everyday Units and Their EXACT Conversions

    11 cm1 inch (in)=2.54 cm1 mile=5280 feet (ft)1 foot= 12 in1 yard=3 ft

  • *Common Units and Their Equivalents

    Volume1 liter (L)=1.057 quarts (qt)1 U.S. gallon (gal)=3.785 liters (L)

    Mass1 kilogram (km)=2.205 pounds (lb)1 pound (lb)=453.59 grams (g)1 ounce (oz)=28.35 (g)

  • *UnitsAlways write every number with its associated unitAlways include units in your calculationsyou can do the same kind of operations on units as you can with numberscm cm = cm2cm + cm = cmcm cm = 1using units as a guide to problem solving

  • *Conversion FactorRelationships to Convert one unit of measurement to another: US dollar Canadian dollar, dollar cent

    Conversion Factors: Relationships between two unitsBoth parts of the conversion factor have the same number of significant figuresConversion factors generated from equivalence statementse.g. 1 inch = 2.54 cm can giveor *

  • *How to Use Conversion FactorArrange conversion factors so starting unit cancelsArrange conversion factor so starting unit is on the bottom of the conversion factorunit 1unit 2unit 1unit 2x=Conversion Factor*

  • *We have been using the Conversion Factor ALL THE TIME! How are we converting #cents into #dollars? Why?From 1 dollar = 100 cents45,000 cents dollarcents450 dollarsx= 1 dollar 100 cents*

  • *Given:325 mgFind:? gConv. Fact.1 mg = 10-3 g Soln. Map:mg gConvert 325 mg to grams0.325 g*

  • Practice: How to set up Conversion?To convert 5.00 inches to cm, from 1 in = 2.54 cm (exact), which one of the two conversion factors should be used?


  • Practice: Conversion among Units500 mg = ? g

    3.78 L = ? mL

    1.2 nm = ? m

    * 8.0 in = ? m*

  • Scientific NotationVery Large vs. Very Small numbers:

    The suns diameter is 1,392,000,000 m; An atoms diameter is 0.000 000 000 3 m

    Scientific Notation: 1.392 x 109 m & 3 x 10-10 mthe sunsdiameter is1,392,000,000 m

  • *Scientific Notation (SN)Power of 10 (Math language): 10 x 10 = 100 100 = 102 (2nd power of 10)10 x 10 x 10 = 1,000 1,000 = 103 (3rd power of 10)

    each Decimal Place in our number system represents a different power of 1024 = 2.4 x 101 = 2.4 x 101,000,000,000 (1 billion) = 1090.0000000001 (1/10 billionth ) = 10-10

    Easily comparable by looking at the power of 10

  • *Exponents 10Ywhen the exponent on 10 (Y) is positive, the number is that many powers of 10 larger suns diameter = 1.392 x 109 m = 1,392,000,000 m

    when Y is negative, the number is that many powers of 10 smalleravg. ato