TEST 2- 17.1-17.7, 17.10, 11 Flashcards
1
Q
First law of thermodynamics
A
energy cannot be created or destroyed, only transferred
2
Q
The internal energy of an isolated system
A
remains constant
3
Q
The total energy of the universe is
A
constant, and change in energy of universe is 0
4
Q
The first law of thermodynamics describes
A
organized energy
5
Q
Second law of thermodynamics
A
all spontaneous energy transfers in the universe serve to increase overall entropy (s) of universe
6
Q
Reversible process
A
does not increase entropy of universe, can be undone by reversing conditions, can be forward or reverse on path
7
Q
Irreversible process
A
does increase the entropy, cannot be undone
8
Q
Spontaneous reaction or change
A
continue to occur on its own without outside forces
9
Q
Spontaneous reactions will result in
A
increase in disorder (entropy) of universe
10
Q
Spontaneous processes do not need
A
continuous input of energy
11
Q
Nonospontaneous process
A
does not occur in specific conditions and requires an input of energy
12
Q
Organized energy of universe
A
goes down, disorganized energy goes. up
13
Q
The second law of thermodynamics describes
A
disorganized energy
14
Q
Third law of thermodynamics
A
as temp increases so does entropy, as temp decreases so does entropy
15
Q
At 0 K
A
absolute 0, entropy is 0
16
Q
Entropy
A
increase in randomness or dispersal of matter and energy in J/Kxmol
17
Q
Standard entropy
A
absolute entropy at pressure 1 atm
18
Q
Microstates
A
all the microscopic distributions of energy among particles in a system that are possible, while maintaining the macroscopic form
19
Q
Entropy related to microstates equation
A
S = Kbln(W)
20
Q
Kb
A
boltzman’s constant- 1.318 x 10^-23 J/K
21
Q
W
A
number of microstates
22
Q
A decrease in pressure or increase in volume
A
Increases entropy
23
Q
A decrease in pressure means an increase in
A
volume, energy has more space to disperse
24
Q
Larger molecule size allows for more
A
microstates and greater entropy
25
Two substances of the same substance in same state
larger sample will have more entropy
26
A process with an increase in the number of gas particles will result in
overall increase in entropy
27
Mixing substances will cause
increase in overall entropy, solid has higher entropy when dissolved than when in solid form
28
Two compounds with similar mass in same phase
more complex means a greater entropy
29
Enthalpy in exothermic processes
enthalpy is negative, system releases energy, heat of surroundings is greater than 0, heat of system is less than 0, and ENTROPY of surroundings is greater than 0
30
Enthalpy in endothermic process
enthalpy is positive, system absorbs energy, heat of system is greater than 0, heat of surroundings is less than 0, and ENTROPY of surroundings is less than 0
31
Energy gained by the surroundings is equal to
the energy lost by the system, qsurroundings = - qsystem
32
Change in entropy of phase change =
change in enthalpy of change divided by temperature where change occured
33
Positive value of change in entropy
increase in entropy, favorable, spontaneous
34
Change in entropy of universe =
Change in entropy of system + change in entropy of surroundings, Change in entropy of system + enthalpy of surroundings / temp
35
Change in entropy surroundings =
- Change in enthalpy system / Temp at constant pressure
36
How to find enthalpy and entropy change for chemical reactions
change in products - change in reactants
37
Free energy
state function that combines enthalpy and entropy
38
Gibbs free energy
usable energy, energy available to do work, Change in Gibbs energy = Change in enthalpy - Temperature (Change in entropy) (entropy of SYSTEM)
39
Exergonic reactions
negative free energy, lose usable energy as the process moves forward, spontaneous in forward direction, nonspontaneous in the reverse
40
Endergonic reactions
positive free energy, gain usable energy, nonspontaneous in the forward, spontaneous in the reerse
41
If gibbs free energy = 0
reaction is in equilibrium and no net change will occur
42
If Change in H is negative and Change in S is positive
reactions are spontaneous at all temperatures
43
If Change in H is negative and Change in S is negative
reactions are spontaneous at low temperatures
44
If Change in H is positive and Change in S is positive
reactions become spontaneous at high temperatures
45
If Change in H is positive and Change in S is negative
reactions are non-spontaneous at all temperatures
46
Solute
substance that experiences a phase change after dissolved
47
Solvent
the media that remains in that same phase after a solution is formed, solute is dissolved in this
48
Molarity and temperature
temperature dependent
49
The sum of mole fractions
always equals 1
50
Mole fraction and temperature
temperature independent
51
Mole fraction
Number of moles of A / number of moles of A + B
52
Molality
m, moles of solute / kg of solvent
53
Molality and temperature
temperature independent
54
Mass percent
Mass of component / total mass of components x 100
55
Mass percent and temperature
temperature independent
56
Parts per million
mass of solute / mass of solution x 10^6
57
Parts per billion
mass of solute / mass of solution x 10^9
58
Parts per million simplified equation
mg solute / kg solution
59
Parts per billion simplified equation
ug solute / kg solution
60
Unsaturated solution
solute's concentration is lower than its solubility
61
Saturated solution
solute's concentration is equal to its solubility
62
Supersaturated solution
solute's concentration is greater than is solubility
63
Miscibility
ability of one liquid to dissolve in another liquid
64
Miscible
liquids successfully mix
65
Immiscible
liquids. do not mix
66
Two liquids are miscible phrase
like dissolves like
67
For a solution to form spontaneously
there is an exothermic change in the system (decrease in internal energy), increase in entropy (increase in disorder)
68
An increase in entropy ALWAYS occurs when
a solution has been made
69
Solutions being combined
is more energetically favorable that liquids on their own
70
Solute molecules need to
separate and spread out from other solute molecules
71
Solute molecules separating is a __ process
endothermic
72
Solvent molecules need to
separate and spread out from other solvent molecules
73
Solvent molecules separating is a __ process
endothermic
74
Solute molecules interacting directly with solvent molecules is a __ process
exothermic
75
Direction formation of a solution is a __ process
exothermic
76
If more energy was required to break bonds in solute and solvent than energy released in solution formation
overall heat of solution is endothermic
77
If the heat of solution is positive (endothermic)
adding heat will increase solubility of the solute
78
If more energy was released in the solution formation than energy required to break the bonds in the solute and solvent
overall heat of solution is exothermic
79
If the heat of solution is negative (exothermic)
adding heat will decrease solubility of the solute
80
As atomic radius of an ion decreases
the heat of hydration is more exothermic
81
As atomic radius of an ion increases
the heat of hydration is more endothermic
82
As the charge of two ions of similar size increases
(same period), the heat of hydration is more exothermic
83
As hydration processes become more exothermic
the process is becoming more spontaneous
84
Henry's law
solubility of a gas in a solution is directly proportional to the partial pressure of the gas
85
As pressure increases, solubility of gas
will also increase
86
As volume increases, solubility of gas
decreases
87
As temperature increases, solubility of gas
decreases
88
Van't Hoff Factor
moles of particles in solution / moles of solute dissolved
89
Experimentally determined VHF will always be
lower than the ideal
90
Percent ionization formula
= (experimental VHF -1) / (ideal VHF -1) x 100
91
Colligative properties depend on
the number of particles of solute and solvent and not the identity of the solute
92
Adding solute to a liquid has the effect of
lowering the vapor pressure
93
Raoult's law
how the vapor pressure of liquid changes as a solute is added to the liquid
94
Raoult's law formula
Vapor pressure of solution = mole fraction of solvent x vapor pressure of pure solvent
95
If we create a liquid-liquid system where both components are volatile
Ptotal = X solv 1 x Vapor pressure solv 1 + X solv 2 x Vapor pressure solv 2
96
Boiling point elevaiton
solute dissolved in liquid, solute lowers vapor pressure of liquid and boiling point increases
97
Boiling point elevation equation
Change in Tb = Kb(m)(I)
98
Freezing point depression
solute dissolved in liquid, solute interrupts ability of liquid to interact which decreases freezing point
99
Freezing point increases when molality
decreases
100
When solute increases, vapor pressure and boiling point
vapor pressure decreases, boiling point increases
101
Osmotic pressure
amount of pressure required to prevent the flow of a pure solvent into a solution through semi-permeable membrane
102
Osmotic pressure equation (pi)
pi = nRT / V (I)
103
R gas constant for osmotic pressure
R = 0.0821 L x atm / mol
104
Osmosis
movement of water from low concentration of solute to high
105
In osmosis solute cannot
move across semi-permeable membrane
106
Entropy increases with __ IMF
decreasing
107
Microstates increase with __ temperature
increasing
108
Temperature increases with __ entropy
increasing
109
Forming bonds
releases energy
110
Formation of solution steps
break solute-solute (exo), break solvent-solvent (exo), form solute-solvent (endo)
111
Favor spontaneous reactions
decrease in internal energy, increase in disorder
112
Ion-dipole attraction
electrostatic, between ion and molecule with a dipole, H2O molecules surround and solvate the separated ions, physical process, dissociation
113
If ion-dipole attraction dominate
compound it pulled in solution is highly soluble
114
If force of attraction between oppositely charged ions is dominate
component is undissolved in solid state, low water solubility
115
Solubility
rate is dissolution is equal to rate of precipitation
116
Supersaturated
concentration is greater than solubility
117
Unsaturated
concentration is lower than solubility
118
Exothermic temperature decreases and solubility
increases
119
Endothermic temperature increases and solubility
increases
120
Ionic and covalent solids
can dissolve
121
Solid dissolving in a liquid
endothermic
122
Solubility of solids __ with increasing temperature
increases
123
Increasing heat favors
formation of products
124
Miscible
two liquids that mix in all properties (ethanol, water)
125
Immiscible
two liquids that do not mix to an extent, NP liquids, gases, hydrocarbonds, water
126
Partially miscible
two liquids that are moderately soluble, bromine, water
127
Dissolution of gas in liquid
exothermic
128
Gas solubility decreases
temperature increases
129
Gas solubility and partial pressure
directly proportional
130
Making supersaturated solutions
high temperature, slowly cool, solid wont precipitate, at low temp solute concentration is greater than compound solubility
131
Molality
moles solute / kg solvent
132
More solute = ___ vapor pressure
decreasing
133
Solution boils at higher or lower temperature than pure solvent
higher
134
Boiling point elevation and freezing point depression are direct results of
vapor pressure lowering
135
Saturated solutions are
at equilibrium
136
Water evaporated unsaturated solution, vapor pressure above solution
decreases
137
Water evaporated saturated solution, vapor pressure above solution
equal
138
Intensive properties
units of concentration do not depend on size or amount
