Changes in MatterChanges in Matter

Physical vs. Chemical Physical vs. Chemical ChangesChanges

Physical ChangesPhysical Changes

No new substance is formedNo new substance is formed The particles are not changedThe particles are not changed Usually just a change of stateUsually just a change of state The change can be reversedThe change can be reversed

• Example:Example: Dissolving Salt in WaterDissolving Salt in Water Dissolving Baking Soda in WaterDissolving Baking Soda in Water

Chemical ChangesChemical Changes

Always creates at least one new Always creates at least one new substance that has new propertiessubstance that has new properties

Can be difficult or impossible to Can be difficult or impossible to reverse (can’t go back)reverse (can’t go back)• ExampleExample

Adding vinegar to baking sodaAdding vinegar to baking soda Burning paperBurning paper

Chemical ChangesChemical Changes

How do we know??How do we know??

The seven observations that aThe seven observations that a

chemical change has occurred:chemical change has occurred:• Heat or light is produced or absorbedHeat or light is produced or absorbed• The starting material is used upThe starting material is used up• A new colour appears or starting colour A new colour appears or starting colour

disappearsdisappears• A material with new properties formsA material with new properties forms• Gas bubbles form in a liquidGas bubbles form in a liquid• Grains of solid precipitate form in a Grains of solid precipitate form in a

liquidliquid• The change is difficult to reverseThe change is difficult to reverse

PrecipitatePrecipitate• A solid or solid phase separated from a A solid or solid phase separated from a

solution solution

Chemical or Physical Change?Chemical or Physical Change?Why?Why?

1.1. Sugar dissolves in waterSugar dissolves in water

2.2. A steak is well cookedA steak is well cooked

3.3. The filament of a light bulb glows The filament of a light bulb glows when electricity runs through itwhen electricity runs through it

4.4. A piece of chalk is crushedA piece of chalk is crushed

5.5. A seed grows into a shrubA seed grows into a shrub

Physical and Chemical Physical and Chemical ChangesChanges

VocabularyVocabulary

Physical VocabularyPhysical Vocabulary

WordWord ExampleExample

GrindingGrinding Rocks, Teeth, coffee, Rocks, Teeth, coffee, wheatwheat

BreakingBreaking Chalk, plate, bones, Chalk, plate, bones, bottlebottle

ErodingEroding Cliffs, beaches, soilCliffs, beaches, soil

EvaporatingEvaporating Water, alcoholWater, alcohol

MeltingMelting Ice, snow, waxIce, snow, wax

CondensingCondensing Water from steamWater from steam

DryingDrying Clothes, paintClothes, paint

More Physical VocabMore Physical Vocab

WordWord ExampleExample

FreezingFreezing Water, vegetablesWater, vegetables

CutCut Wood, paper, meatWood, paper, meat

StretchStretch Elastic, rubber bandElastic, rubber band

Crumple/CrumbleCrumple/Crumble cookie, buildingscookie, buildings

SplitSplit WoodWood

Chemical VocabularyChemical Vocabulary

WordWord ExampleExample

BurningBurning Wood, nylon, paperWood, nylon, paper

RottingRotting Food, wood, teethFood, wood, teeth

RustingRusting Cars, metal, toolsCars, metal, tools

ReactionsReactions Vinegar, baking sodaVinegar, baking soda

DigestingDigesting Food in stomachFood in stomach

RespirationRespiration Gasses formedGasses formed

PhotosynthesisPhotosynthesis Changes in plantsChanges in plants