thermodynamics Flashcards
what is an open system?
able to exchange heat, work and matter with surrounding
what is closed system ?
able to exchange heat and work but NOT matter with the surroundings
what is an isolated system?
not able to exchange heat , work and matter with surroundings
what is the ideal gas equation?
pV = nRT
p= pressure (atm)
V=volume occupied by gas (L)
n=number of moles od substance in gaseous state
T= temperature (Kelvin) +273
R= ideal gas constant (L.K-1.mol-1)
give 2 example of non thermodynamic properties
heat (q)
work (w)
what is heat in thermodynamics?
heat is the exchange of energy between thermodynamic systems by thermal interactions.
what is molar heat capacity cm? J K-1 mol-1
Amount of energy required to increase the temperature of 1 mol of a substance by 1 Kelvin.
what is work in thermodynamic systems?
work is then exchange of energy between thermodynamic. systems by any other interaction than thermal.
what is specific heat capacity cs? J K-1 g-1
Amount of energy required to increase the temperature of 1 g of a substance by 1 Kelvin.
what is the equation for heat energy?
q = m x c x change in T
the c can be cs or cm
q= heat energy
m= mass in grams
n= number of moles
cs= specific heat capacity
cm= molar heat capacity
T= change in temperature (K)
what is the first law of thermodynamics?
states that the internal energy (U) is the total energy of a thermodynamics system.
what is the equation for internal energy?
sum of heat energy and work
ΔU = q + ω
what is bond energy?
the amount of energy stored in a chemical bond between two atoms
how do you calculate total energy stored in a compound?
find all the bonds in the compound and add all the energy together that is stored to find the total energy
what is the equation for enthalpy
ΔH = sum E(reactants) – sum E(products)
what are exothermic reactions?
the sum of energy of bonds formed is greater than the sum of energy of bonds broken
energy released from system
what is endothermic
sum of energy of bonds formed is smaller than sum of energy of bonds broken.
energy used
as water boils and evaporates the water molecules progress from a more ordered state to a more disordered state of steam. true or false?
true
what does entropy (S) mean?
a measure of disorder in thermodynamic system
what is the second law of thermodynamics?
states that any spontaneous process must lead to an increase in the disorder of the system and therefore lead to an increase in entropy.
equation for Gibbs free energy?
ΔG = ΔH – TΔS
s= entropy
T= temp
what is the third law of thermodynamics?
is related to the entropy of the thermodynamic system and states that the entropy of a perfect crystalline material is zero at T= 0K
