The States of Matter AC Physical Science Fall 2009

Solids… Has a definite volume and definite shape Has a definite volume and definite shape Particles are packed very tightly together Particles are packed very tightly together Particles stay in a fixed position Particles stay in a fixed position

Types of solids… Crystalline - made of crystals…examples: salt, sugar, sand, snow – melts at the melting point Crystalline - made of crystals…examples: salt, sugar, sand, snow – melts at the melting point Amorphous solid – solids not arranged in a regular pattern…examples: plastics, rubber, and glass – does not have a distinct melting point. Instead the material becomes softer as it is heated. Amorphous solid – solids not arranged in a regular pattern…examples: plastics, rubber, and glass – does not have a distinct melting point. Instead the material becomes softer as it is heated.

Liquids… Has no shape of its own Has no shape of its own Takes the shape of the container Takes the shape of the container Do not expand or compress easily Do not expand or compress easily Particles packed closely Particles packed closely Particles move around freely Particles move around freely Viscosity – resistance of a liquid to flowing or how easily a liquid flows…high viscosity flows slowly (molasses) and low viscosity flows fast (water, rubbing alcohol, engine oil). Viscosity – resistance of a liquid to flowing or how easily a liquid flows…high viscosity flows slowly (molasses) and low viscosity flows fast (water, rubbing alcohol, engine oil).

Gases… Changes volume very easily Changes volume very easily Volume and shape is the same as the container Volume and shape is the same as the container Does not have definite shape or volume Does not have definite shape or volume Feel your chest expand and contract when you breathe. Feel your chest expand and contract when you breathe.

Pressure… Force of the outward push on a container exerted by a gas Force of the outward push on a container exerted by a gas Pressure = Force / Area Pressure = Force / Area Pressure is related to volume Pressure is related to volume Boyle’s Law – relationship between pressure and volume of a gas…when pressure is increased at a constant temperature – the volume of the gas decreases…when the pressure decreases, volume increases Boyle’s Law – relationship between pressure and volume of a gas…when pressure is increased at a constant temperature – the volume of the gas decreases…when the pressure decreases, volume increases

Temperature… Charles’ Law – when temperature of a gas increases at a constant pressure, the volume increases…when temperature decreases, volume decreases Charles’ Law – when temperature of a gas increases at a constant pressure, the volume increases…when temperature decreases, volume decreases

Plasma??? Defined as an “Ionized Gas” – in other words dealing with the sharing of electrons… Defined as an “Ionized Gas” – in other words dealing with the sharing of electrons… Plasma is considered a conductor and is strongly attracted to electromagnetic fields. Plasma is considered a conductor and is strongly attracted to electromagnetic fields. Examples: lightening, the ionosphere, and the aurora borealis – all occurring in nature. In space – the sun and stars (created by fusion), solar winds and space itself is said to be plasma. Man-made plasma…TV’s, neon signs, fluorescent lamps, etc. Examples: lightening, the ionosphere, and the aurora borealis – all occurring in nature. In space – the sun and stars (created by fusion), solar winds and space itself is said to be plasma. Man-made plasma…TV’s, neon signs, fluorescent lamps, etc.

Chemical Properties and Changes… Chemical Properties – the chemical makeup of a substance Chemical Properties – the chemical makeup of a substance Chemical Changes – occurs when compounds are created or destroyed…breaks in chemical bonds occur - should included color change, bubbles, or a precipitate (a crystalline solid) forming…examples: burning wood, mixing an acid with a base, melting a piece of plastic…a simple state change does NOT always mean a chemical change has occurred. Chemical Changes – occurs when compounds are created or destroyed…breaks in chemical bonds occur - should included color change, bubbles, or a precipitate (a crystalline solid) forming…examples: burning wood, mixing an acid with a base, melting a piece of plastic…a simple state change does NOT always mean a chemical change has occurred.

Physical Properties and Changes… Sublimation – solid changes to gas – happened at really cold temperatures…the solid does not go through the liquid state (dry ice). Sublimation – solid changes to gas – happened at really cold temperatures…the solid does not go through the liquid state (dry ice). Physical Properties – observable properties of a substance (color, size, etc.) Physical Properties – observable properties of a substance (color, size, etc.) Physical Changes – change that occurs without changing the identity of the substance (wood being chopped…carrots being sliced)… Physical Changes – change that occurs without changing the identity of the substance (wood being chopped…carrots being sliced)…