3 Physical Properties A physical property describes the substance E.g. StateHardnessMelting pointBoiling pointOdourSolubilityColourMalleabilityDuctilityEtc.
4 Chemical PropertyA chemical property is how the substance reacts to form a new substance.E.g.How it reacts with acidHow it reacts with waterHow it reacts with oxygenEtc.
5 Physical ChangeA physical change is when the original substance does not turn into a new substance but does change form.E.g.Ripping a piece of paperDissolving a saltMelting ice
6 Chemical ChangeWhen a substance changes from one substance into another, it is a chemical change.E.g.Baking soda in acidIron exposed to oxygenCombustion
7 How to Recognize a Chemical Change Clues that a chemical change has occurred.A new colour appearsHeat or light is given offBubbles of gas are formedA precipitate (solid) forms in a liquidThe change is difficult to reverseE.g. 2H2(g) + O2(g) 2H2O(l)
8 Chemical TestsYou can use chemical change to perform a chemical test to determine if a substance is present.Glowing splint used to indicate if oxygen is presentA burning splint is used to indicate if hydrogen is presentLimewater can be used to indicate if carbon dioxide is presentCobalt chloride paper can be used to indicate if water is presentA flame test can tell which type of metal is presentFlame test for Li
9 Do you remember? WHMIS? MSDS? Provides Canadian workers with the information on the safe use of hazardous materials in their workplace.MSDS?Material safety data sheet
10 Try These….Classify each of the following observations as an example of either a chemical property or a physical property. [K]Propane, leaking from a damaged tank, ignites easily.Silver jewellery tarnishes (darkens) in airSpilled oil generally floats on the surface of water.What type of change is describes in each of the following? [K]A loud pop is heard when a lit match is placed inside of a test tube.Air is often blended into ice cream in order to give it a lighter quality.Drain cleaners often produce a great deal of heat as they unclog drains. Is the action of the drain cleaner a chemical or physical change? [A]Over time, crusty scales form on the heating coils inside a kettle. These can be removed by covering the coils with vinegar. As the scales disappear, bubbles of gas are observed. Does this method of cleaning a kettle represent a physical or chemical change? Explain. [A]