Chapter 12 - Properties of Matter

12.1 – Properties of Solidspp. 270-275 &

17.1 Chemical Reactionspp. 384-387

PROPERTIES OF SOLIDS

• Different kinds of matter have different characteristics.

• Characteristics that you can observe directly are called physical properties.

• Substances can be identified by their physical properties.

Physical Properties

Can be observed or measured without changing the identity of the matter

Include: • Color ∙odor ∙mass• Volume ∙density ∙solubility• Malleability ∙ductility• State of matter• Thermal conductivity

malleability

The ability to be pounded into thin sheetsExample: Aluminum can be rolled or pounded into sheets to make foil

ductility

• The ability to be drawn into a thin wire

• Example: copper can be drawn into a thin wire

Density

• Formula used to calculate density

• D = m V

Where D = density (measured in g/cm3)

m = mass (measured in g)

And V= volume (measured in cm3)

DENSITY OF A SOLID

• Depends on two things:

–The mass of the object

–How tightly packed together the atoms are.

TWO TYPES OF SOLID

• Crystalline solid

particles are arranged in a repeating pattern of rows.

Ex.: diamond, ice, iron, salts, minerals, metals

• Amorphous solid

Particles are not in any particular order

Examples include: oobleck, rubber, wax, glass

• Tensile strengthA measure of how much stress from pulling a material can withstand before breaking. Brittle materials have low tensile strength.

• Hardnessmeasure's a solid’s resistance to scratching.

Ex.: MOH’S scale of hardness.

• Elasticity• This describes a solid's ability to

be stretched and return to its original shape.

• Brittleness- the tendency of a solid to crack or break before stretching very much.Glass is a brittle material.

Physical Changes

• A change that affects one or more physical properties of a substance

• Physical changes can be undone

• Examples: freezing water for ice cubes

• Cutting your hair

• Bending a paper clip

Chemical Properties

• describe a substance based on its ability to change into a NEW substance with DIFFERENT properties

Include: 1. flammability (the ability to burn)2. Reactivity to oxygen3. Reactivity with water4. Reactivity with acids

Chemical Change

• A chemical change occurs when one or more substances are changed into COMPLETELY DIFFERENT substances with DIFFERENT PROPERTIES

• Example: baking a cake

+ +

=

Clues to Chemical Changes

• Change in color• Fizzing• Foaming• Heat• Production of sound, light or odor

Chemical Changes

• Cannot be undone by ordinary physical means

• Some chemical changes may be undone by other chemical means– Example: Water formed in the space shuttle’s

rockets could be split back into hydrogen and oxygen using electricity