The Four Phases Phase Changes Boyle’s Law & Charles’s Law Chapter 3 The Four Phases Phase Changes Boyle’s Law & Charles’s Law

Matter exists in four phases: SOLID LIQUID GAS PLASMA

Phases of Matter

SOLIDS Have a definite shape Have a definite volume Particles packed very closely together – they are sometimes arranged in a regular repeating pattern called a CRYSTAL Particles may only vibrate – too close to move Some particles are NOT arranged in a pattern – called AMORPHOUS solids – and may lose their shape over time under certain conditions Examples include: window glass, candle wax, tar, silicone rubber

LIQUIDS Have no definite shape – particles are free to move or flow because they are not as closely packed Have a definite volume – but must take the shape of its container Some liquids flow more freely than others VISCOSITY is a liquid’s resistance to flow Which is more viscous – HONEY or WATER? Oil & other lubricants have high viscosity

GASES No definite shape No definite volume Particles are free to move so they fill the available space, regardless of the size or shape of the container What holds Earth’s atmospheric gases so they don’t expand into deep space? Particles are in constant motion – moving so fast that they’re colliding with each other & the container at great speeds

PLASMA Rarely found on Earth Very common in the universe (stars, like our sun) Matter is extremely high in energy Very dangerous to living things

BEHAVIOR of GASES Because the particles of a gas are in constant motion, changing the temperature of or the pressure on the particles will have an effect on the behavior of the particles in the space (volume) they occupy Two laws help us understand the relationship

Boyle’s Law P2 V1 With a fixed amount of gas: when the pressure increases, the volume decreases when the pressure decreases, the volume increases This is an inverse proportion P1 = V2 P2 V1

Charles’s Law T2 V2 With a fixed amount of gas: when the temperature increases, the volume increases when the temperature decreases, the volume decreases This is a direct proportion T1 = V1 T2 V2

Which law is being shown in this cartoon?

PHASE CHANGES Substances will change from one phase to another by adding (absorbing) or taking away (releasing) ENERGY Adding energy causes the particles in a substance to move faster & spread out Releasing energy causes the particles in a substance to slow down & come together Example = water vapor, liquid water, & ice

Phases changes are beneficial: This is why freezing water can “save” fruit by the release of energy which the fruit takes on This is also why evaporation of water or sweat from the skin is a cooling process

Phases changes include: MELTING – change from a solid to a liquid FREEZING – change from a liquid to a solid VAPORIZATION – change from a liquid to a gas (like evaporation) CONDENSATION – change from a gas to a liquid

Phase Changes

Sublimation Examples include: dry ice, fallen snow, air freshener Some substances are able to change from a solid state directly to a gaseous state without ever becoming a liquid Examples include: dry ice, fallen snow, air freshener

Melting Point vs. Freezing Point The temperature at which a solid changes to a liquid The temperature at which a liquid changes to a solid They’re equal to each other, meaning water will melt & freeze at 0°C

What is happening at X? What is the temperature?

Evaporation vs. Boiling Evaporation occurs when a phase change (liquid to gas) occurs from the surface of the liquid Boiling causes the phase change to occur within the liquid & gas bubbles rise to the top

Condensation vs. Boiling Point The temperature at which a gas changes to a liquid The temperature at which a liquid changes to a gas They’re equal to each other, meaning water will condense & boil at 100°C

Phase Change Graph for Water