AP chem Unit 6

requires energy, high PE

solid to gas

releases energy, low PE

gas to solid

require energy

melting and evaporating

release energy

freezing and condensation

phase changes

on a graph flat lines are

states themselves

on a graph slants are

temp and KE are constant

on flat lines of the graph

up

endothermic heating curve goes

q=(moles)(deltaHvap)

heat of vaporization

q=-(moles*deltaHvap)

heat of condensation

q=(moles)(fusion)

heat of fusion (melt)

down

exothermic cooling curve goes

q=(moles)(-fusion)

heat of solidification (freeze)

-q

cool

q

heat

qsystem=-qsurrounding

q surroundings

qsolution/moleLR

heat of neutralization

qsol/molesol

molar heat/enthalpy of solution

mass of salt + mass of water

mass surroundings

Cp=J//g*C or Cp=J/mol*C

heat capacity

qlost=-qgained

qlost

KE goes down

temp goes down

thermal equilibrium

both have same KE and temp

break IMFs, absorb, energetically UNFAVORABLE

endothermic/ deltaH

release energy, form IMFs, energetically FAVORABLE

exothermic/-deltaH

stability goes DOWN

as PE goes UP

Hf=0

for pure elements in standard state