Studied by 1 person
q in
endothermic, positive q
q out
exothermic, negative q
work done on system by surroundings
contractive, positive w
work done by system on surroundings
expansive, negative w
heat
total energy of all particles
temperature
average speed of all particles
equilibria
heat content isn’t the same, but the temperature and heart flow is the same both ways
why is exothermic spontaneous?
in exothermic reactions, the products are more stable
exothermic reaction energy diagram
delta H is negative
endothermic reaction energy diagram
delta H is positive
if (w → 0)
delta E = q, proportional to delta T
if (q → 0)
delta E = w = F d, proportional to P * delta V
melting and freezing
melting - expansion
freezing - contraction
Hfusion
boiling and condensation
boiling - expansion
condensation - contraction
Hvaporization
sublimination and deposition
sublimination - expansion
deposition - contraction
state property
a propertiy in which we only care about the initial and final state, not the pathway in which we got there
calorimetry
study of heat transfer using a calorimeter
specific heat
the amount of heat it takes to increase one gram of a substance by one degree celcius
delta H =
-qwater
bomb calorimeter is used when
there is lots of gas and high temperatures
qrxn =
-qcalorimeter = -Ccalorimeter * delta T
qsystem
qbomb+qH2O
phase change diagram
when the graph goes up
q = m * c * delta T
when the phase change graph stays constant
w = m * Hx (x can be fusion or vaporization, it depends)
thermochem rule #1
delta H is directly propertional to the amount of reactands or products
thermochem rule #2
delta T for a reaction is equal in magnitude but opposite sign to delta H in reverse
thermochem rule #3
hess’ law
Hf
delta H when one molecule of stable compound is formed
bond energies
delta H when one mole of bonds are broken in the gaseous state
breaking bonds
positive
forming bonds
negative
lattice energy
energy released when two gaseous ions react to form a solid product
Hsolution
ionization energy + sphere of hydration
increasing lattice energy
least to most exothermic
Note 
Flashcard (84)