unit 5 - chemH vocab

energy

the ability to do work or produce heat

potential energy

so tired energy based on position if an object

kinetic energy

energy an object has due to its motion

thermal energy

sum of all the potential and kinetic energies an object has

temperature

measure of the average kinetic energy of all particles of a given substance (relates to speed of particles)

intermolecular forces (IMFs)

forces of attraction that cause particles of matter to “stick together” (attraction between particles)

exothermic

process where energy is released ( will have (-) sign when the change of energy is calculated)

endothermic

process where energy is absorbed (will have a (+) sign when the change of energy is calculated)

ethalpy (H)

official term for total “heat content” of a system (total thermal energy contained in a sample)

calorie (cal)

alternative unit of energy used in chemistry due to its relationship to heating and cooling water

energy needed to heat 1 gram of water by 1 degree C

Calorie (Cal)

dietary nutrition

Specific heat capacity ( c ) - reference value

heating or cooling one gram of a substance by one degree celsius

J/g degree celsius or cal/g degree celsius

molar heat of phase change - reference value (delta H degrees)

1 mole of a substance undergoing a phase change

KJ/mol or Kcal/mol

heat source

hotter thing - molecules traveling at greater speeds

Heat sink

molecules traveling at slower speeds

thermal equilibrium

heat continues to flow between the two objects until they have the same temperature (exchange energy until they are traveling at the same average speed)

phase boundaries

division between separate phases

phase equilibrium

rate of change into one state is the same as the rate of change into other state (ex. rate of vaporization is equal to the rate of condensation) occurs on all points directly on the boundary

triple point (T)

temperature and pressure at which solid, liquid, and gas phases exist simultaneously (end of solid-liquid phase boundary)

critical point ( c )

temperature above which a substance will always be a gas regardless of the pressure

super critical fluid

state of any substance at a temperature and pressure above its critical point where distinct liquid and gas phases don’t exist (in between liquid and gas)

vapor pressure

pressure of the vapor resulting from evaporation of a liquid

“volatility” - how easily a substance enters the vapor phase

boiling point

temperature at which vapor pressure of the liquid is equal to the atmospheric pressure

normal boiling point

temperature at which a substance boils at standard pressure

normal melting point

temperature at which a substance melts at standard pressure

mixture

physical blend instead of a chemical bond

homogeneous mixture

uniformly distributed; mixture is the same throughout

heterogeneous mixture

no uniform throughout the mixture

solution

homogeneous mixture of very small particles

solute

substance that dissolves ; present in smaller amounts

solvent

the substance that does the dissolving; present in larger amounts

colloid

a type of homogenous mixture that the particles are dispersed and evenly distributed and do not settle out

suspension

a heterogeneous mixture that contains solid particles sufficiently large that they will settle if left out standing

soluble (general)

able to dissolve in a certain solvent

insoluble (general)

not able to dissolve in a certain solvent

miscible

when two liquids are mixed they will for a homogeneous structure

immiscible

when two liquids are mixed together and they are not capable of forming a homogeneous mixture (i.e. water and oil)

dissolving

when a solid becomes incorporated into a liquid

concentrated

having a relatively large amount of solute dissolved in the solvent

dilute

a relative low amount is solutes dissolved in the solvent

to make a solution thinner or less concentrated by adding water or another solvent to it

saturated

maximum amount is solute has been dissolved

unsaturated

concentration is lower than it could be, there is still more room to dissolve more solute

supersaturated

solution that contains more of the dissolved material that could be dissolved by the solvent under normal circumstances

solubility

the maximum amount is solute that can dissolve in a given temperature and pressure (amount is solute that will saturate the solvent)

colligative properti w

property of a solution that depends on the with or solute dissolved, not the identity of the solute (all solutes behave in the same manner)