2 Characteristic Properties The properties that are most useful in identifying a substance are its characteristic properties.Remember the difference between physical and chemical properties.Physical properties can be observed! (with your eyes!) IDENTITY OF SUBSTANCE DOES NOT CHANGE!You can observe chemical properties only in situations in which the identity of the substance could change.
3 Types of PropertiesPhysical: properties that can be observed without changing the IDENTITY of the matterA physical property is a property or characteristic of and object or substance that can be observed, described, and measured without changing the matter.Chemical: property of a substance that changes it into a NEW substance (changes the identity of the substance)
4 What are physical properties? A physical property is a property or characteristic of and object or substance that can be observed, described, and measured without changing the matter.
5 Mass The amount of matter Triple beam balance to measure Definition:The amount of matterExample:Triple beam balance to measureMeasured in gram units
6 Volume Irregular objects: Water displacement Definition:how much space the matter takes upExample:Irregular objects: Water displacementRegular objects use measurementLiters or m31ml = 1cm3
7 Density D=M/V Mass per unit volume g/l, g/ml, or g/cm3 Definition:Mass per unit volumeExample:D=M/Vg/l, g/ml, or g/cm3Lead is used for fishing weights because it is more dense than water
8 More information about density... Density = The amount of matter in a given space or volumeDensity = m Massv Volume
9 More information about density... Most substances have a unique density:Water = 1.00 g/mLGold = g/mL(See page 13 in your book for a bigger list)Density < 1 - The object will float in waterDensity > 1 – The object will sink in water
10 State The form in which matter exists: solid, liquid, gas, or plasma Definition:The form in which matter exists: solid, liquid, gas, or plasmaIce = SolidWater = LiquidHelium = GasLightning = Plasma
11 Luster The ability to reflect light Shiny: more reflection Definition:The ability to reflect lightShiny: more reflectionDull: less reflection
12 Thermal ConductivityDefinition:The ability to transfer thermal energy (heat) to something elseExample:Coffee in a special cup to prevent heat transfer to our hands
13 Electrical Conductivity Definition:The ability to conduct electricity (the atoms allow their electron to move or flow)Example:Metals and non metalsConductors – good conductivityInsulators – no conductivity
14 The ability to be pounded into thin sheets MalleabilityDefinition:The ability to be pounded into thin sheetsExample:Aluminum can be pounded flat to make aluminum foil
15 Ductility The ability to be drawn into thin wires Definition:The ability to be drawn into thin wiresExample:Copper is used to make wires
16 SolubilityDefinition:The ability for one substance to dissolve into another substanceExample:Drink mix dissolves in water or sugar dissolves in coffee
17 Physical ChangesA physical change is a change that affects one or more physical properties of a substance.Physical changes do not form new substances! EX: ice melting or sugar dissolvingPhysical changes are easy to undo.
18 Chemical Propertiesproperty of a substance that changes it into a NEW substance (changes the identity of the substance)Chemical properties describe a substance based on its ability to change into a new substance with different properties.Chemical properties cannot be observed with your senses.Chemical properties aren’t as easy to observe as physical properties.Examples of chemical properties: flammability and reactivityEx: wood burns to form ash and smoke
20 Chemical ChangesA chemical change occurs when one or more substances are changed into entirely new substances with different properties.You can observe chemical properties only when a chemical change might occur!Examples of chem. changes:baking a cakerusting
21 Clues to chemical changes Color changeFizzing or bubbling (gas w/odor production)Production of lightTemperature (heat or cold)Precipitate (something new falls to the bottom)Chemical changes are not usually reversible! You can not undo fire.