States of Matter

• States of Matter – physical forms that substances can exist in

• Matter is composed of atoms and molecules that are always in motion bumping into each other, this activity determines the state of the matter

Solids

• Particles of solids do not move fast enough to over come the strong attraction between them, therefore, they are close together and vibrate in place

• Solids have a definite shape and volume• Crystalline – orderly 3 dimensional

arranged particles in repeating patterns of rows

• Ex; ice, diamonds, iron

• Amorphous – no special arrangement or pattern

• Ex; rubber, wax

Liquids

• Particles of a liquid move fast enough to over come some of the attraction between the particles, therefore, the particles are close together but can slide past each other

• Can change shape but not volume, liquids take the shape of the container they are in

Properties specific to liquids

• Surface tension – force that acts on the surface of liquids and that tends to minimize the area of the surface

• Different liquids have different surface tensions• Ex: water has high surface tension and forms

spheres, gasoline has low surface tension and forms flat drops

• Viscosity – resistance of liquids to flow because of the attraction of the molecules in the liquid, stronger the attraction, the greater the viscosity

Gases

• Particles of a gas move fast enough to over come almost all of the attraction between them, therefore, the particles are far apart and move independently of each other (empty space between them)

• Gases change shape and volume• Gases can expand and shrink depending on the

space they are put in• Volume of a gas depends on the container the

gas is in

• Pressure - is the force exerted on a given area of surface (the number of times the particles of gas hit the inside of the container)-psi units

• Compression – a property of a gas, the ability to squeeze or compress a gas into a smaller space

Plasma

• Hot ionized (atoms are positively charges and share space with free negatively charged electrons) gas that can conduct electricity

• Lightening is plasma, stars are plasma

Gas Laws

• Boyles Law – relationship between volume and pressure, – as volume decreases, pressure increases– as volume increases, pressure decreases

• When temperature is constant

Gas Laws

• Charles Law – temperature effects the volume of a gas when pressure is constant– Temperature decreases (particles move

slower) the volume of a gas decreases– As temperature increases (particles move

quicker) the volume of the gas increases

Changes of state

• All changes of state are physical changes• All states of matter have energy (solids

less energy, gases more energy)• To change the state of matter, you must

add or remove energy• Adding energy – (solid to liquid) melting

point is the point where added energy allows the molecules to over come their attraction to each other (endothermic)

• Removing energy (liquid to a solid) freezing point is the point where molecules being to overcome movement and the particles of matter lock in place (exothermic)

• Evaporation – (liquid to gas) at the surface below the matters boiling point

• Boiling – (liquid to vapor or gas) pressure inside the bubble is equal to the pressure on the outside of the bubble – boiling point

• Condensation – (gas to liquid) particles must clump together when the attraction between the particles over comes movement, energy must be removed

• Sublimation – (solid directly to gas) attraction must be completely overcome, energy is added

• When substances lose or gain energy either the temperature changes or the state changes

• temperature is related to the speed the particles are moving

• When temperature changes, the speed of the particles changes, causing a change in state

• Temperature change doesn’t happen until the change of state is complete

Temperature Change of H2O

• Boiling Point/evaporation/condensation• 100 °C , 212 °F or 373 K

• Freezing point/melting point• 0 °C , 32 °F or 273 K

• Absolute Zero – point at which all matter stops moving and time no longer affects the matter

(0 Kelvin, -273.15 °C, -459.67 °F)