2.1 States of Matter

The particles that make up a solid are packed very closely together and are tightly fixed in one position.
🗝 %%This fixed, closely packed arrangement of particles in solid causes it to have a definite shape and volume.%%
The particles in a solid are closely locked in position and can only vibrate in place.

$crystalline solid$ * A solid that is made up of crystals in which particles are arranged in a regular, repeating pattern. * Examples: salt, sugar, and snow.
$amorphous solid$ * A solid made up of particles that are not arranged in a regular pattern. * Examples: glass, plastic, rubber.
Unlike a crystalline solid, an amorphous solid does not melt at a distinct temperature. Instead, it may become softer and softer or change into other substances.

$liquid$ * A state of matter that has no definite shape but had a definite volume. * The shape of a liquid may change with its container, but its volume remains the same.

In general, the particles in a liquid are packed almost as closely together as those in a solid. However, the particles in a liquid move around one another freely.
🗝 %%Because its particles are free to move, a liquid has no definite shape. However, it does have a definite volume.%%
$fluid$ * Any substance that can flow.

$surface tension$ * The result of an inward pull among the molecules of a liquid that brings the molecules on the surface closer together; causes the surface to act as if it has a thin skin. * Examples: a sewing needle floats when you place it gently on the surface of water but quickly sinks if you push it below the surface, a water strider can walk on the calm surface of a pond
Due to surface tension, the surface of water can act like a sort of skin.
$viscosity$ * A liquid’s resistance to flowing. * Examples: honey has very high viscosity, water and vinegar have relatively low viscosities
A liquid’s viscosity depends on the size and shape of its particles and the attractions between the particles.
Liquids with high viscosity flow slowly.

$gas$ * A state of matter with no definite shape or volume.
If a gas is in a closed container, the gas particles will move and spread apart as they fill the container.
🗝 %%As gas particles move, they spread apart, filling all the space available. Thus, a gas has neither definite shape no definite volume.%%

Volume is the amount of space that matter fills.
Volume is measured in cubic centimeters (cm^3), cubic meters (m^3), mililiters (mL), liters (L), and other units.
Because gas particles move and fill all of the space available, the volume of a gas is the same as the volume of its container.

$pressure$ * The force pushing on a surface divided by the area of that surface. * Example: the air inside an inflated ball has a higher pressure than the air outside because there is a greater concentration of has particles inside the ball than in the surrounding air.
Concentration is the number of gas particles in a given unit of volume.
Pressure is measured in units of pascals (Pa) or kilopascals (kPa)
Pressure = Force/Area
The firmness of a gas-filled object comes from the pressure of the gas.

Temperature is a measure of the average energy of random motion of the particles of matter.
The faster the particles are moving, the greater their energy and the higher the temperature.
A thermometer is like a speedometer for particles.