thermochemistry

entropy

measures disorder or spontaneity of system (S)

enthalpy

measures the heat transferred (H)

positive S

increase in disorder/spontaneity

negative S

decrease in disorder/spontaneity

S, H, G = 0

equilibrium

positive H

endothermic

negative H

exothermic

positive G

thermodynamically unfavorable (reaction unlikely)

negative G

thermodynamically favorable (reaction likely)

when is G thermodynamically favorable?

positive S, negative H

thermochemistry

study of how heat changes in chemical reactions

heat

total kinetic energy transferred between substances measured indirectly in J, cal, kcal

temperature

average kinetic energy of a substance measured directly

hess law

when going from reactants to products, the enthalpy change is the same no matter how many steps