2.2 PROPERTIES OF MATTERI can:

- classify matter by its chemical and/or physical properties (e.g. color solubility, odor, hardness, density, melting point, and boiling point, viscosity and malleability)

- recall differences of physical and chemical properties

STEEL IS A MIXTURE OF IRON, OTHER METALLIC ELEMENTS, AND CARBON

PHYSICAL PROPERTIES

• Any characteristic of a material that you can observe without changing the identity of the substances that make up the material is a physical property.• Examples of physical properties are color, shape, size, density, melting point, and boiling point.

Appearance

How would you describe a tennis ball?• shape, color, and state of matter. physical properties- diameter, mass,

etc.

Behavior

Some physical properties describe the behavior of a material or a substance.

• Attraction to a magnet is a physical property of the substance iron. (magnetism)

• The ability to flow is another (water vs. molasses)

PHYSICAL PROPERTIES DESCRIBE MATTER

• Help ID a substance• Senses: shape, color, odor, texture

• Some can be measured• Melting point• Boiling point

• Physical properties typically remain constant.• Pure water is always a colorless liquid, never powdery green solid.

• Observable physical property= STATE of that matter.

DENSITY IS A PHYSICAL PROPERTY

• The ratio of the mass of a substance to volume of a substance.

• Why do hot air balloons float?

• Why do stones sink?

• Brick v. sponge?

• D=m/V• Desity=mass/volume

GOLF BALL V. PING PONG

• Both have similar volume.

• Golf ball: 45.9g

• Ping pong ball: 2.5g

• Golf ball has more mass per unit volumn.

PRACTICE

• If 10.0 cm3 of ice has a mass of 9.17 g, what is the density of the ice?

• List the given and the unknown values• M=9.17 g• V= 10.0 cm3

• D= ?

• Plug them in• D= 9.17g/ 10.0 cm3

• D= 0.917 g/cm3

PHYSICAL PROPERTIES HELP DETERMINE USES

• How to you tell if your socks are clean?• odor

• Whether or not your homework will fit in your bag?• Volume

• If your shirt matches your pants?• Color

• Is copper good for electricity?• Conductor

• Will antifreeze remain in liquid form in low or high temps?• Boiling/freezing point of ethylene glycol

EXAMPLES OF CHEMICAL PROPERTIESSodium=reacts very fast (found as compounds)

Gold= much less reactive (found uncombined)

Magnesium= very reactive (emergency flares)

Argon= not reactive (light bulbs last longer)

CHEMICAL PROPERTIES DESCRIBE HOW A SUBSTANCE

REACTS.• Problem= iron reacts with oxygen. What does this cause?

• Solution: paint prevents steel from coming in contact with oxygen.

• Other chemical properties:• Reactivity: the ability of a substance to combine chemically with another.• Flammability: the ability of a substance to react in the presence of oxygen

and burn when exposed to a flame.• Burning wood creates new substance… ash• Gold has chemical property of nonflammable.

COMPARING PHYSICAL AND CHEMICAL PROPERTIES