2 Physical propertiesPhysical properties can be observed or measured without changing the identity of the matter.Basically, properties you notice when using one of your five senses:Feel - mass, volume, textureSight - colorHearSmellTaste
3 Physical properties of matter are categorized as either: Intensive or Extensive: Intensive - Properties that do not depend on the amount of the matter present.ColorOdorLuster - How shiny a substance is.Malleability - The ability of a substance to be beaten into thin sheets.Ductility - The ability of a substance to be drawn into thin wires.
4 Conductivity - The ability of a substance to allow the flow of energy or electricity. Hardness - How easily a substance can be scratched.Melting/Freezing Point The temperature at which the solid and liquid phases of a substance are in equilibrium at atmospheric pressure.Boiling Point - The temperature at which the vapor pressure of a liquid is equal to the pressure on the liquid (generally atmospheric pressure).
5 More Physical Properties Density is a very important property.It is the amount of matter in a given volume.Density = Mass / Volume
7 A. Physical PropertiesPhysical properties can be described as one of 2 types:Extensive Propertydepends on the amount of matter present (example: length)Intensive Propertydepends on the identity of substance, not the amount (example: scent)
8 B. Extensive vs. Intensive Examples:boiling pointvolumemassdensityconductivityintensiveextensive
9 Extensive - Properties that do depend on the amount of matter present. Volume -A measurement of the amount of space a substance occupies.*Length
10 V is for VolumeBriefly, volume is the amount of space something takes up.Whether it’s a speck of dust or Jupiter, all matter takes up space.
11 Measuring the volume of… Liquids:Graduated cylinderDisplacement methodMeasured in liters (L) & milliliters (mL)Solids:Length x width x heightGases:Since a gas expands to fill its container, if you know the volume of the container, you know the volume of the gas.
12 Density - The mass of a substance divided by its volume Density is an important physical property. Density is the mass of a substance per unit volume.Volume is the amount of space an object occupies.
13 C. Density – a physical property Derived units = Combination of base unitsVolume (m3 or cm3 or mL)length length lengthOr measured using a graduated cylinder1 cm3 = 1 mL1 dm3 = 1 LDensity (kg/m3 or g/cm3 or g/mL)mass per volumeD =MV
14 C. Density V = 825 cm3 M = DV D = 13.6 g/cm3 M = (13.6 g/cm3)(825cm3) An object has a volume of 825 cm3 and a density of 13.6 g/cm3. Find its mass.GIVEN:V = 825 cm3D = 13.6 g/cm3M = ?WORK:M = DVM = (13.6 g/cm3)(825cm3)M = 11,220 gM = 11,200 g
15 C. Density D = 0.87 g/mL V = M V = ? M = 25 g V = 25 g 0.87 g/mL A liquid has a density of 0.87 g/mL. What volume is occupied by 25 g of the liquid?GIVEN:D = 0.87 g/mLV = ?M = 25 gWORK:V = MDV = 25 g0.87 g/mL= mLV = 29 mL
16 Physical Properties - Examples Other physical properties include:ColorHardnessOdorTasteState of matterTextureLuster (shine)FlexibilityHeat conductivityElectrical conductivitySolubility (ability to dissolve in water.)ShapeViscosityDuctilityMalleability
17 D. Chemical Properties Chemical Property describes the ability of a substance to undergo changes in identity
18 Chemical properties A common chemical property is reactivity. Reactive to oxygenReactive to airReactive to water…Notice that chemical properties aren’t EASY to observe, unlike physical properties.
19 Chemical properties - Examples Examples of chemical properties include:The ability to burnAbility to tarnishAbility to rustAbility to decomposeAbility to react with other chemicalsInstabilityAbility to do acid/base reactions
21 Physical vs. ChemicalPhysical properties: observe without changing the identity of the substanceChemical properties: observe only when the identity changesHow do you know if it is chemical or physical?If it CHanges, it’s CHemical
22 E. Physical vs. Chemical Properties Examples:melting pointflammabledensitymagnetictarnishes in airphysicalchemical
23 Chemical and physical properties – So what? Titanium is very strong and doesn’t rust, so it is often used in jet engines.Titanium is also nonallergenic. This, combined with the fact that it is rust proof makes it great for artificial joints as well as piercings.
24 Chemical and physical properties – So what? Tungsten is usually used as the filament in lightbulbs because it has the highest melting point of any metal.It glows red hot when electricity runs through it, and it gives off both heat and light.
25 Chemical and physical properties – So what? Vanadium is heavier and harder than titanium, so mixing a tiny bit of vanadium with steel can make cheap tools that are still very strong.
26 Chemical and physical properties – So what? Helium is almost completely nonreactive (inert).It is lighter than air, so it’s great for floating balloons (or making funny voices.)When electricity runs through helium, it glows a creamy pale peach color.
27 Chemical and physical properties – So what? In 1943, all US pennies were made of zinc plated steel because copper was being used in the war. The pennies had to be coated with zinc because steel will rust, but zinc won’t.
28 Chemical and physical properties – So what? Sulfur smells awful. Rotten eggs, onions, and garlic all have sulfur in them. Stink bombs use sulfur to create a bad smell.Sulfur is also flammable, and it is one of the 3 main ingredients in gun powder.
29 Chemical and physical properties – So what? Chromium is famous for its intense luster. Chrome plated tools, jewlery, silverware, or car parts are very popular.
30 Chemical and physical properties – So what? Most bullets are made of lead because lead is a very dense metal. These bullets are required, by international law, to be coated with a different metal because lead has such a low melting point and is so malleable.
31 Chemical and physical properties – So what? The most dense elements are Iridium and osmium which have a density of about 22.6 g/cm3
32 Physical ChangeA Physical change is a change in a substance that does not change what the substance is.
33 Physical Change - examples Examples of physical change include:Change in shapeChange in sizeChange in phaseMelting (solid to liquid)Boiling (liquid to gas)Evaporation (liquid to gas)Condensation (gas to liquid)Freezing (liquid to solid)Sublimation (solid to gas)Deposition (gas to solid)
34 Physical Change Physical changes might be caused by: Grinding Cutting CrushingBendingBreakingHeating/cooling(change in phase)squishing
35 Physical ChangeEvidence that a physical change has occurred might include:Change in shapeChange in formChange in sizeChange in phase (This is always a physical change!)Physical changes are usually reversible
36 Chemical changeA chemical change is a change in which a substance is changed into a different substance. (You’ve changed what it is.)
37 Chemical change Examples of chemical changes include: Burning Rusting TarnishingDecomposingPolymerization
38 Chemical changeChemical changes occur when a chemical reaction causes bonds between atoms to break or to form.
39 Chemical change – Chemical reactions There are 5 types of chemical reactions that cause chemical changes to occur.
40 Chemical change – Chemical reactions 1- Composition reactionsTwo things come together to form something newA + B = AB2H2 + O2 2H2O
41 Chemical change – Chemical reactions 2- Decomposition reactions1 thing breaks apart to form 2 or more things.AB = A + B2H2O 2H2 + O2
42 Chemical change – Chemical reactions 3- Single replacement reactionsOne atom replaces another atomA + BC = AC + B or A + BC = AB + CMg + 2HCl H2 + MgCl2
43 Chemical change – Chemical reactions Double replacement reactionsTwo chemicals switch placesAX + BY = AY + BX2KI + Pb(NO3)2 PbI2 + 2KNO3
44 Chemical change – Chemical reactions Combustion reactionA substance combines with oxygen and releases energy.C3H8 (propane) + 5O2 3CO2 + 4H2O
45 Chemical Change: Evidence Evidence that a chemical change has occurred might include:A color changeAn odor changeFormation of a precipitate (you mix two liquids and make a solid)Gas is formed (bubbles)Changes in physical properties.
46 Physical and Chemical change During a chemical change energy can be released in the form of:HeatLight
47 Physical and Chemical change - heat A chemical reaction that releases energy in the form of heat is called exothermic.Heat comes OUTExo = outThermic = heatIt will feel HOT.
48 Physical and Chemical change - heat A chemical reaction that absorbs energy in the form of heat is called endothermic.Heat goes INEndo = inThermic = heatIt will feel COLD
49 I. Law of Conservation of Mass Although chemical changes occur, mass is neither created nor destroyed in a chemical reactionMass of reactants equals mass of productsmassreactants = massproductsA + B C
50 I. Conservation of Mass GIVEN: WORK: 10.00 g = 9.86 g + moxygen In an experiment, g of red mercury (II) oxide powder is placed in an open flask and heated until it is converted to liquid mercury and oxygen gas. The liquid mercury has a mass of 9.26 g. What is the mass of the oxygen formed in the reaction?GIVEN:Mercury (II) oxide mercury + oxygenMmercury(II) oxide = gMmercury = 9.86 gMoxygen = ?WORK:10.00 g = 9.86 g + moxygenMoxygen = (10.00 g – 9.86 g)Moxygen = 0.74 gMercury (II) oxide mercury + oxygenMmercury(II) oxide = gMmercury = 9.26Moxygen = ?massreactants = massproducts