Matter and Change

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5.- DENSITY

6.- MELTING POINT

7.- BOILING POINT

Matter and Change

Slide 15

Matter and Change

Physical properties help chemists

identify a substance based on their characteristics.

Which substance is this?

“Colorless liquid that boils at 100 ˚C and melts at 0 ˚C” ???????

“Colorless liquid that boils at 78 ˚C

and melts at -117 ˚C” ???????

Slide 16

Matter and Change

Slide 17

Solids

Matter and Change

Coal, sugar, ice and iron.

Definite shape and volume.

The shape doesn’t depend on the shape of their container.

The particles are packed tightly together, they are almost incompressible.

Solids expand only lightly when heated

Slide 18

Liquids

Matter and Change

Water, milk and blood.

Takes the shape of their container (flows).

Particles are packed closely together, but not rigidly packed.

The volume that a liquid occupies is always constant, no matter what shape it takes.

Almost incompressible, with a tendency to expand when heated.

Slide 19

Gases

Matter and Change

Takes the shape and form of their container (flowable).

Particles are spaced far apart.

Gases expand without limit to fill any space.

Gases are easily compressed.

Slide 20

Vapor

Matter and Change

The gaseous state of a substance that is generally a liquid or solid at room temperature.

Steam (the gaseous state of matter) is referred to as a vapor because water is a liquid at room temperature.

Moist air contains water vapor.

Slide 21

Physical change

Matter and Change

A type of change that alters a given material without changing it’s chemical composition.

Examples include: cutting, grinding, bending, the melting of the metal gallium, the freezing of water and the condensation of steam to water.

Slide 22

Matter and Change

PHYSICAL CHANGE

Other verbs or actions related to physical changes include: boil, freeze, dissolve, melt, condense, break, split, crack, grind, cut, crush and bend.