cornerstone 9th grade science ch 16.1

kinetic theory

an explanation of how particles in matter move

thermal energy

the total kinetic and potential energy of all the particles in a substance.

temperature

average kinetic energy of a substance

in most substances, as temperature increases

the kinetic energy and disorder of the particles increase

thermal expansion

the expanding of matter when it is heated

water expands

when it changes from a liquid to a solid

amorphous solids

no definite melting point
liquefy over a temperature range

liquid crystals

maintain some geometric order in the liquid state

3 assumptions of kinetic theory

1. all matter composed of small particles
2. particles re in constant motion
3.particles are constantly colliding

movement of particles of solids

vibrate in place

movement of particles of liquids

slide past each other

movement of particles of gases

move freely and randomly and collide with one another

describe the movement of particles at the melting point of a substance

particles gain enough kinetic energy to slip out of their ordered arrangement

describe the movement of particles at the boiling point of of a substance

particles in the liquid overcome the downward pressure and escape from the liquid

would the boiling point of water be higher or lower on the top of a mountain peak

lower because atmosphere pressureis lower.

how would the boiling point be affected in a pressurized boiler system

higher, the pressurized boiler system creates a higher pressure above the liquid

boil cup of soup for lunch, drop ice cube in to cool down. how many states of matter are there. how are these states alike and different.

steam from soup = gas
ice cube= solid
soup = liquid
alike in that all composed of water molecules.
different in the amount of kinetic energy the molecules contain and the distance between the particles.

how are kinetic energy and temperature related

temperature is the average kinetic energy of the particles of a substance

why do liquids flow

the particles have gained enough kinetic energy to partially escape the attractiveforces in the solid

what is heat of fusion

the amount of energy required to change a substance from the solid state to the liquid state at its melting point

heat of vaporization

the amount of energy required for the liquid at its boiling point to become a gas

how does external pressure affect the boiling point of a liquid

at greater atmospheric pressure (lower elevation) the boiling point is a higher temperature than at less atmospheric pressure (higher elevation)

diffusion

spreading of particles throughout a given volume until they are uniformly distributed. Diffusion occurs in solids and liquids but occur most in gases.

plasma

matter consisting of positively and negatively charged particles.

2 examples of amorphous solids

glass and plastic