2.2 PROPERTIES OF MATTER I 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 cm 3 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 cm 3 D= ? Plug them in D= 9.17g/ 10.0 cm 3 D= g/cm 3

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 PROPERTIES Sodium=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