Grade 8 Chemistry Properties of Matter 8

Properties of matter grade 8 chem

1. PROPERTIES OF
MATTER
DESCRIBING MATTER

2. HOW WOULD YOU DESCRIBE
YOURSELF SO THAT SOMEONE
ELSE COULD IDENTIFY YOU?
•Onaseparatesheetofpaper,write
asmanyphysicaldescriptionsof
yourselfasyoucan.Donotputyour
nameonthepaper.

3. PHYSICAL
PROPERTIES
•APROPERTY OFMATTER THATCANBE
OBSERVEDORMEASUREDWITHOUTCHANGING
THEIDENTITYOFTHEMATTER.
•PHYSICALPROPERTIESIDENTIFYMATTER.
•EXAMPLESINCLUDEBUTARENOTLIMITEDTO:
•DENSITY
•MALLEABILITY
•DUCTILITY
•SOLUBILITY
•STATE
•THERMALCONDUCTIVITY

4. PHYSICAL PROPERTIES
•DENSITY
•Amountofmassinagivenvolume
•Asubstanceisalwaysthesameatagiven
pressureandtemperatureregardlessofthe
sizeofthesampleofthesubstance.
•Thedensityofonesubstanceisusually
differentfromthatofanothersubstance.
•Densityequalsmassdividedbyvolume.
•D = M / V

5. PRACTICE
•AbarofcopperhasAmassof216ganda
volumeof24cmᴲ.
•Whatisthedensityofcopper?
•Thevolumeofacandybaris55cmᴲ.The
massofthecandybaris70g.WhatSthe
densityofthecandybar?

6. MORE PRACTICE
•Anicecubehasavolumeof36
cmᴲ.Iftheicecubehasamass
of33.2g,whatisthedensityof
theicecube?
•Whatisthedensityofwater?

7. STILL MORE PRACTICE
•At4⁰C,purewaterhasadensityof1g/ml
(1g/cmᴲ).Supposethatyouhave2liters
ofpurewateratthistemperature.Whatis
themassofthiswater?
•Whatisthemassofethylalcoholthat

8. AND YET, TWO MORE : )
•What is the mass of ethyl alcohol that
exactly fills a 200.0 ml graduated
cylinder. The density of ethyl alcohol is
0.789 g/ml.
•What is the volume of a silver metal
that has a mass of 2500.0 g. The
density of silver is 10.5 g/cmᴲ

9. PHYSICAL PROPERTY
•MALLEABILITY
•The ability to be pounded into thin sheets.
Example:
•Aluminum can be rolled or pounded into
sheets to make foil.
•DUCTILITY
•The ability to be drawn or pulled into a wire
Example
•Copper in wiring –soldering wires or
joints

10. PHYSICAL PROPERTY
•SOLUBILITY
•The ability to dissolve in another
substance.
•EXAMPLE:
•Sugar or salt dissolve in water
Three ways to increase solubility
•Heat or make warmer
•Grind or smash
•Stir or mix

11. PHYSICAL PROPERTY
•STATE OF MATTER
•The physical form in which a substance
exists at room temperature, such as:
•Solid–matter has a definite shape and
volume
•Liquid–matter takes the shape of its
container and has a definite volume
•Gas–matter changes in both shape and
volume

12. PHYSICAL PROPERTY
•THERMAL CONDUCTIVITY
•The ability to transfer thermal
energy from one area to another.
•Examples:
•Plastic foam is a poor conductor, so
a hot drink won’t burn your hand.
•The inside of the toaster (hot coils)

13. CHEMICAL PROPERTY
•Apropertyofmatterthatdescribesa
substancebasedonitsabilityto
changeintoanewsubstancewith
differentproperties.
•Combustibility
•Flammability
•Reactivity
•Acids
•Bases
•Oxidation

14. CHEMICAL PROPERTIES
Canbeobservedwithyoursenses.
Arenotaseasytoobserveas
physicalproperties
Example:
flammability–onlywhenwood
burns
Combustibility–onlywhen
fireworksexplode
Reactivity–onlywheniron
oxidizes(rust)

15. PHYSICAL CHANGE
•A change that affects one or more physical
properties of a substance.
•Do not form new substances.
•Can often be undone
•Example butter on counter can be placed
back in refrigerator.
•Change of state
•Solid to liquid
•Liquid to gas

16. CHEMICAL CHANGE
•Achangethatoccurswhenoneormore
substancesarechangedintoentirelynew
substanceswithdifferentproperties.
•Cannotchangebackundernormal
conditions(somecanbechangedbackby
otherchemicalmeans)
•Commonexamples:
•Reactivity–oxidation(rust)onabicycle
•Ph(acid/base)–effervescenttablets
•Flammability–burntwood
•Combustibility-fireworks

17. 5 SIGNS OF A CHEMICAL CHANGE
•Theonlysurewaytoknowtherehas
beenachemicalchangeisthe
observanceofanewsubstance
formed
•Sometimesthatishardtodo,so
lookforthesigns…….

18. SIGN 1 A CHEMICAL CHANGE
•Odor production-this is an odor far
different from what it should smell
like
•Ex: rotting eggs, food in fridge,
decomposing flesh

19. 2
ND
SIGN OF A CHEMICAL CHANGE
•Changeintemperature
•Exothermic-whenenergyisreleased
doduringthechemicalchangeex:
woodburning

20. CHANGE IN TEMPERATURE
•ENDOTHERMIC-Energyisabsorbed
causingadecreaseintemperatureof
thereactantmaterialex:coldpackin
firstaidkit

21. 3
RD
SIGN OF A CHEMICAL CHANGE
CHANGE IN COLOR
Ex: fruit changing color when it
ripens, leaves changing color in the
autumn, dying your hair

22. 4
TH
SIGN OF A CHEMICAL CHANGE
•FORMATION OF BUBBLES
•Thiscanindicatethepresenceofagas.
Bubblesproducedwhenboilingwateris
notachemicalchange.

23. 5
TH
SIGN OF A CHEMICAL CHANGE
•FORMATIONOFAPRECIPITATE
•Whentwoliquidsarecombinedanda
solidisproduced