128 definitions Flashcards
state functions
V-volume, T-temp., P-pressure, C-heat capacity, U-internal energy, H-enthalpy, S-entropy, G-gibbs free energy
heat
transfer of thermal energy between bodies existing at different temperatures
=q
calorie
energy needed to raise 1g H2O by 1°C
Heat Capacity
C=mc
UNITS: g=(J/g*°C)
Specific Heat
energy to raise 1g of substance by 1°C
system
what we are interested in
solution, molecules, reaction
surroundings
everything else (not the system)
bulk water, table, air, work bench
thermal equilibrium
different temperature items+contact=thermal equilibrium
+q
endothermic, consuming energy/heat into system
-q
exothermic, producing heat
+w
work done on/to the system, volume/pressure increasing like an engine piston
-w
work done by the system
work equation
w= P - deltaV
internal energy equation
deltaU= q+w
solving for heat under a constant V
deltaU = q
solving for heat under a constant P
q = deltaU + (P) (deltaV)
enthalpy of formation (delta Hf)
energy change resulting from formation of 1 MOLE PRODUCT FROM ITS ELEMENTS in standard state
the energy we need to put into something to create it
H in standard state is 0
enthalpy of combustion (delta Hc)
energy change from combusting (combining w O2) 1 MOLE OF FUEL; typically a hydrocarbon fuel
usually combustion has a fraction of O2 moles, here it is okay because we are needing 1 mole of fuel
Enthalpy of Reaction (delta Hrxn)
energy change from a chemical reaction
= sum of (moles) (Hf products) + (moles) (Hf reactants)
+ delta H reaction
endothermic, energy of products is higher than energy of reactants
- delta H reaction
exothermic, energy of products is lower than energy of reactants
vaporization
liquid to gas
endothermic, +deltaHvap
condensation
gas to liquid
exothermic, -deltaHvap
melting
solid to liquid
endothermic, +deltaHfusion
