PHYSICALProperties

- characteristics that can be observed or measured without changing the composition

- Ex. Breaking a glass, dying your hair

- Color, density, odor, taste, melting, freezing & boiling point, magnetism, solubility

Some, but not all physical changes can be reversed. You could

refreeze the water into ice, but you cannot put your hair back together if you don’t like your

haircut!

CHEMICALProperties

- ability of a substance to combine with or change into 1 or more other substances

Ex. Combustible, reactivity, flammability, rusts,

Obla Di Obla Da – The Properties Songhttp://www.youtube.com/watch?v=uJOGy0dgmUU

http://www.teachertube.com/viewVideo.php?video_id=129193

Physical changes are those changes that do not result in the production of a new substance.

If you melt a block of ice, you still have H2O at the end of the

change.

If you break a bottle, you still have glass. Painting your nails will not stop them from being

fingernails. Some common examples of physical changes

are: melting, freezing, condensing, breaking, crushing,

cutting, and bending.

Some, but not all physical changes can be reversed. You could

refreeze the water into ice, but you cannot put your hair back together if you don’t like your

haircut!

Special types of physical changes where any object changes state, such as when water freezes or

evaporates, are sometimes called change of state operations.

CHEMICAL PROPERTIES

Chemical properties can ONLY be observed AS the substances are changing into different substances.

Chemical changes, or chemical reactions, are changes that result in the production of

another substance.

FLAMMABILITY: A material’s ability to BURN in the presence of OXYGEN

REACTIVITY:How readily (easily) a substance combines chemically with other

substances.

Which has higher reactivity? A 14 karat gold ring or a cheap metal ring from the vending machine at the grocery store?

What is your evidence?

When you burn a log in a fireplace, you are carrying out a chemical reaction that releases carbon. When you light your Bunsen

burner in lab, you are carrying out a chemical reaction that produces

water and carbon dioxide.

Common examples of chemical changes that you may be

somewhat familiar with are; digestion, respiration,

photosynthesis, burning, and decomposition.

Physical or Chemical Change?

•Painting Wood•PHYSICAL

Physical or Chemical Change?

•Burning Paper•CHEMICAL

Physical or Chemical Change?

•Digestion of food•CHEMICAL

Physical or Chemical Change?

•Sugar dissolving in water

•PHYSICAL

Physical or Chemical Change?

•Iron turning red when heated

•PHYSICAL

Physical or Chemical Change?

•Evaporation•PHYSICAL

Physical or Chemical Change?

•A pond freezing in winter

•PHYSICAL

Physical or Chemical Change?

•Melting ice•PHYSICAL

Physical or Chemical Change?

•Cutting wire•PHYSICAL

Physical or Chemical Change?

•Painting fingernails•PHYSICAL

Physical or Chemical Change?

•Cutting fabric•PHYSICAL

Physical or Chemical Change?

•Baking muffins•CHEMICAL

Physical or Chemical Change?

•Shattering glass•PHYSICAL

Physical or Chemical Change?

•Decomposition of old leaves

•CHEMICAL

Physical or Chemical Change?

•Wrinkling a shirt•PHYSICAL

Physical or Chemical Change?

•An old nail rusting•CHEMICAL

Classify each statement as physical or chemical property/change.

1. Pure metals have a higher luster (are shiny and reflect light).2. The surfaces of some metals become dull when exposed to air.3. Nitrogen gas, a relatively nonreactive material at room

temperature, can form nitrogen oxides at the high temperatures of an operating automobile engine.

4. Milk turns sour if left too long at room temperature.5. Diamonds are hard enough to be used as a coating for drill bits.6. Leavened bread dough increases in volume if it allowed to “rise”

before baking.7. Generally, metals are better conductors of heat and electricity than

are nonmetals.8. Unreactive argon gas, rather than air, is used to fill many light bulbs

to prevent the metal filament wire inside the bulb from being destroyed through chemical reactions.

9. Metals are typically ductile (can be drawn into wires).

Classify each statement as physical or chemical property/change.

1. Pure metals have a higher luster (are shiny and reflect light).2. The surfaces of some metals become dull when exposed to air.3. Nitrogen gas, a relatively nonreactive material at room

temperature, can form nitrogen oxides at the high temperatures of an operating automobile engine.

4. Milk turns sour if left too long at room temperature.5. Diamonds are hard enough to be used as a coating for drill bits.6. Leavened bread dough increases in volume if it allowed to “rise”

before baking.7. Generally, metals are better conductors of heat and electricity than

are nonmetals.8. Unreactive argon gas, rather than air, is used to fill many light bulbs

to prevent the metal filament wire inside the bulb from being destroyed through chemical reactions.

9. Metals are typically ductile (can be drawn into wires).

PC

CC

P

C

P

CP

Real Life Problem: Designing the Penny

• COST of materials is an issue when manufacturing coins and paper money.– Early 1980’s copper became too expensive to be used as

primary metal in pennies– Zinc replaced most of the copper in all post 1982

pennies

PROs - Zinc – about as hard; almost as dense, readily available and less expensive than copperCONs – more chemically reactive (zinc-plated steel pennies created in 1943 corroded and looked considerably different)

• Solved the penny issue in early 1980s• Copper properties best fit for outside of the coin

and zinc properties best fit for inside of the coin

(increase coin’s durability and maintain familiar appearance)

PHYSICALChanges

CHEMICALChanges

- changes that alter a substance’s appearance without changing its composition

- chemical reactions- process that involves 1 or

more substances changing into new substances

- Ex. Cutting paper, breaking crystals, melting/freezing ice, boiling water

Ex. combusts, rusts, reacts with oxygen, ferments, burns, rots

http://www.teachertube.com/viewVideo.php?video_id=214083

http://vital.cs.ohiou.edu/steamwebsite/downloads/ChangeLab.swfOnline Quiz

What is Density?

Density is the Mass per unit Volume

Wood Water Iron

1 cm3 1 cm3 1 cm3

If you take the same volume of different substances, then they will weigh different amounts.

0.50 g 1.00 g 8.00 g

Q) Which has the greatest mass and therefore the most dense?

IRON

http://www.youtube.com/watch?v=GMNpPgLT8Fk

Density = massVolume

g

mL (for liquids)

or cm3 (for solids)g/mL or g/cm-3

Density Equation:

M = D x VV = M / D

http://science360.gov/obj/video/f2511bad-b43f-4dbd-84f9-ace57941ac90/mass-volume-density

NHL Hockey Rinks

DENSITY OF A REGULAR SOLID1. Find the Mass of the solid on a balance.2. Measure the three lengths and calculate the Volume. (ie V = l x w x h )

• Calculate the Density.

4.0 cm

2.0 cm

3.0 cm

= m = 240 =10.0 g/cm3

V 24

m = 240 g

DENSITY OF AN IRREGULAR SOLID

1. Find the Mass of the solid on a balance.2. Fill the Measuring Cylinder with Water to a known Volume.3. Add the Object.4. Work out the Volume of Water that is displaced.5. Calculate the Density.

50 ml

80 ml

m = 360 g

Density = m = 360 =12.0 g/cm3

V 30

DENSITY OF AN IRREGULAR SOLID• OR use a Eureka (overflow) Can to find the Volume.

1. Find the mass of the solid on a balance.2. Add water until just overflowing.3. Place a Measuring Cylinder under the spout.4. Add the Object.5. Collect the Water and read off the Volume. 6. Calculate Density

m = 440 g

40.0 ml

Density = m = 440 =11.0 g/cm3

V 40

DENSITY OF A LIQUID1. Find the Mass of an empty graduated cylinder.2. Add a certain Volume of Liquid.3. Find the Mass of the Measuring Cylinder and Liquid4. Calculate the Mass of Liquid.– How?

• Mass of Liquid = Mass of Measuring Cylinder and Liquid – Mass of empty Measuring Cylinder

• Calculate Density of Liquid.

25.0 g

20.0 ml

45.0 g

45 – 25 = 20 gDensity = m = 20 =1.00 g/mL V 20

25.0 g

Density Practice Problems1. What is the density of a piece of wood that has a mass of

25.0 grams and a volume of 29.4 cm3?

2. A piece of wood that measures 3.0cm by 6.0cm by 4.0 cm has a mass of 80.0 grams. What is the density of the wood?

3. Would the piece of wood in #2 float in water? Yes, the wood’s density is less than the density of water (1.0g/cm3)

Density = m V

D = 25.0g 29.4cm3

D = 0.85g/cm3

Volume = l x w x hDensity = m V V = 3.0cm x 6.0cm x 4.0cm

V = 72.0cm3

m = 80.0g

D = 80.0g 72.0cm3

D = 0.85g/cm3

4. An ice cube measuring 5.80cm by 5.80cm by 5.80cmhas a density of 0.917g/cm3. What is the mass?

5. The density of aluminum is 2.7g/ml. If the mass of a piece of aluminum is 244g, what is the volume of the aluminum?

Volume = l x w x hDensity = m V m = D x V

V = 5.8cm x 5.8cm x 5.8cmV = 195.11cm3

D = 0.917g/cm3

m = 0.917g/cm3 x 195.11cm3

m = 178.92g

D = 2.7g/mlm = 244g

D = m VV = m D

V = 244g 2.7g/ml

V = 90.37ml

http://www.youtube.com/watch?v=LiAvDpl5aJA

How to TEST for GASSES!

Oxygen (O2), Hydrogen (H2) & Carbon Dioxide (CO2) colorless and odorless (for the most part)….

SOOO how can you tell which gas is emitted after a chemical reaction?????