Unit 6 Flashcards
System
the place that the experiment is held
surroundings
everything that surrounds the system
open system
energy and matter is transfered from surroundings
closed system
only energy is transferred from the surroundings
isolated system
nothing is transferred from the surroundings
State Function
a measurement of thermodynamics that only depends on the initial and final states, nothing in between matters
extensive properties
properties at non standard states
intensive properties
properties at standard states, signified by naught
standard state
1 atm
1 mol/whatever stochiometric coeff
exo -
negative value
endo -
positive value
Kinetic Energy (KE) equation
1/2 (mass)(volume)^2 = (kg) x (m/s)^2 = Joules
Potential Energy (PE)
stored energy
Potential Energy equation
K(qq / r ) = (constant) [(charges) / (distance)]
Energy equation
E = PE + KE
First Law of Thermodynamics
Law of Conservation
Energy cannot be created or destroyed
How do we measure Energy?
heat
Specific heat
Raising one gram of a substance by one C
1 calorie is…
4.184 Joules
heat equation (q)
q = mcΔT
m = mass in grams
c = specific heat
T = temp change in Kelvin or C
What is the unit of heat?
JOULES
Equation of Delta E
q + w
= (heat) + (work)
q + PΔV
Hess’s Law
Operation performed on equation is performed on the heat of the reaction
Formation Reaction
Where reactants are made from their basic elements from their purest form
1 mol
1 atm
Heat of Formation
the amount of heat needed for a formation reaction
ΔH (naught) equation for a reaction
Σ(ΔH of formation of products) - Σ(ΔH of formation of reactants)
OR
ΔH ≈ Σ(bond energies of reactants) - Σ(bond energies of products).
specific heat capacity vs molar heat capacity
one gram vs one mol
If work is done ON the system, the sign is…
+
If work is done BY the system, the sign is…
-
Enthalpy
Heat produced or absorbed by a reaction
Delta H/Enthalpy change equation
(H products) - (H reactants)
Bomb Calorimeter
Constant Volume
Bomb Calorimeter Equation of Delta E
ΔE = q_v
Pressure constant Calorimeter
ΔE = ΔH - PΔV
Energy needed to break bonds are always…
positive
What does Gibbs Free Energy Measure?
Determining the amount of energy available from any chem reaction, which determines spontaneity
Gibbs Free Energy Equation
ΔG = ΔH - TΔS
OR
ΔG _0 (products) - ΔG _0(reactants)
What type of reactants are spontateous?
NEGATIVE G value
ΔG _0
At standard temp
ΔG _0 and ΔG relationship
ΔG = ΔG° + RTlnQ
When is Q = K, and what does K tell us?
at equilibrium
k > 1 = products are favored, spontaneous
k < 1 = reactants are favored, nonspontaneous
Entropy (S)
The number of disorders in a system
higher particles mean…
(entropy wise)
higher entropy
higher volume mean..
(entropy wise)
higher entropy
change of state (!) mean…
(entropy wise)
higher entropy
above all, more gaseous particles mean…
higher entropy
Entropy for
elements are…
NOT zero, like delta H and delta G
Boltzmann Equation - Entropy
S = k ln W
k = constant
W = microstates
Delta S naught
ΔS° = Σ (ν * S°(products)) - Σ (ν * S°(reactants))
Entropy in a reversable process
S = q rev / T = ( heat added) / (T) = J / K
