Unit 1: Physical and Chemical Equilibrium Flashcards
1
Q
If samples contain the same molecule at the same temperature, the samples will have the same ________________________
A
vapor pressure
2
Q
condensation
A
gas to liquid
∆H < 0, ∆S < 0
3
Q
deposition
A
gas to solid
∆H < 0, ∆S < 0
4
Q
sublimation
A
solid to gas
∆H > 0, ∆S > 0
5
Q
vaporization
A
liquid to gas
∆H > 0, ∆S > 0
6
Q
freezing
A
liquid to solid
∆H < 0, ∆S < 0
7
Q
fusion
A
solid to liquid (melting)
∆H > 0, ∆S > 0
8
Q
ice melts at _°C
A
0°C
9
Q
enthalpy (change in ∆H)
A
transfer of heat energy at constant pressure
10
Q
organized molecular motion
A
work
11
Q
entropy (∆S)
A
the dispersal of energy at constant temperature
12
Q
free energy (∆G)
A
the energy available to do work
13
Q
∆G is zero at….
A
phase changes at phase change temp. because that’s when its at equilibrium
14
Q
for samples with the same compound, the sample with the highest VP will have the highest ___________________
A
temperature
15
Q
The normal boiling point is the boiling point at _________
A
1 atm
16
Q
A gas cannot be liquefied ____________ its critical temperature
A
above
17
Q
supercritical fluid
A
particles have so much kinetic energy
no IMFs
in-between liquid and gas
particles are close together like in liquids or very far apart
going from a gas to a SCF or a liquid to a SCF is NOT a phase transition.
18
Q
solute
A
can be solid, liquid, or gas
dissolved in the solvent
19
Q
solvent
A
the major component in a solution
usually a liquid
20
Q
solution
A
solutes are dissolved into solvents to form solutions
they are homogenous mixtures
21
Q
When you increase the temperature of a solution that has a solid solute, the solubility ____________.
A
increases
(i.e. more solid dissolves)
22
Q
When you increase the temperature of a solution that has a gaseous solute, the solubility ___________
A
decreases
(i.e. the gas bubbles out of the solution)
23
Q
Henry’s Law
A
the amount of gas dissolved into a solvent is proportional to the pressure of the gas above the solvent
Cgas (molarity) = Kh (Henry law constant) x Pgas
24
Q
You can melt ice by applying ___________ pressure because the solid/liquid line has a ___________ slope
A
higher, negative
25
triple point
the temperature and pressure at which three phases are in equilibrium
26
∆H solvation =
energy released when solute interacts and forms IMFs with the solvent
27
∆H lattice energy =
energy required to pull apart solute
28
Most dissolution processes are _______________ when the solute is a solid.
This is because the ∆HLE is _________ and the ∆Hsolvation is ___________
endothermic, positive, negative
29
Dissolution of a gaseous solute =
exothermic
30
strong electrolytes are molecules that __________ break into 2 or more ions when dissolved in a solvent
always
31
strong electrolytes =
100% dissociation
32
weak electrolytes are molecules that ____________ break into 2 or more ions when dissolved in a solvent
sometimes
33
weak electrolytes =
between 0% and 100% dissociation
34
nonelectrolytes are molecules that __________ break into 2 or more ions when dissolved in a solvent
never
35
nonelectrolytes =
0% dissociation
36
Molarity
the number of moles of solute per liter of solution (unit = mol/L = M)
37
Molality
the number of moles of solute per kilogram of solvent (unit = mol/kg = 𝓂)
38
Boiling Point Elevation
The boiling point of a solution will be higher than the pure substance (ex. salt water will have a higher boiling point than pure water)
∆Tb = iKbm(solute)
39
Freezing Point Depression
The freezing point of a solution will be lower than the pure substance (ex. salt water will have a lower freezing point than pure water)
∆Tf = -iKfm(solute)
40
Vapor Pressure Lowering (Raoult’s Law)
The vapor pressure of a solution will be lower than the pure substance (ex. salt water will have a lower vapor pressure than pure water)
41
Osmosis
Explains the movement of solvent between solutions of different concentrations separated by a semi-permeable membrane
42
the only thing that affects the vapor pressure of a substance is the _______________
temperature
43
Chemical equilibrium is a ____________ process
dynamic
44
The reaction quotient is represented by the variable __ and it is used at ______________
Q, any point in the reaction
45
The activity of a substance tells us...
how the free energy changes during the reaction progression
46
Equilibrium
a reversible chemical reaction or physical change where the rates of the forward and backward reactions are equal
47
The best mass action expression will show the proper ratio of products to reactants in _________
pressure
48
At equilibrium, the system is at the __________ free energy and ∆G is now _______
lowest, zero
49
Q is only equal to K at __________
equilibrium
50
Kc = Kp when...
the number of gas molecules are the same on both sides.
51
When the standard change in free energy (ΔGr°) is negative, the reaction favors the ____________. The point of equilibrium will be closer to the ______________
products, product-side
52
When the standard change in free energy (ΔGr°) is positive, the reaction favors the ___________. The point of equilibrium will be closer to the __________.
reactants, reactant-side
53
K < 1 and ∆G° > 0
reaction favors the reactants
54
K > 1 and ∆G° < 0
reaction favors the products
55
Q = K and ∆G = 0
reaction is at equilibrium
56
K > 1 and ∆G° > 0
does not exist
57
K < 1 and ∆G° < 0
does not exist
58
Le Chatelier's Principle states: If a chemical system at equilibrium experiences a(n) _________, then the equilibrium shifts to counteract the imposed change and a new _____________ is established.
change, equilibrium
59
For the dissolution to be endothermic, ∆Hsolution must be __________, so two values must add to a ___________ number
positive, positive
60
What increases the solubility of a gas in water?
decreasing the temp. of the water
increasing the pressure of the gas above the water
61
Very small K =
reactant-favored; makes more reactants, thus more products need to be made to reach equilibrium
62
1-ish K =
mix of reactants and products (somewhere in middle)
63
Very large K =
product-favored; makes more products, thus more reactants need to be made to reach equilibrium
64
always ignore ________________ in the mass action expression
solids and liquids
65
inverse of ln
e^x
66
When total pressure increases, a reaction at equilibrium will shift to the side with...
fewer number of moles of gas
67
Q < K
more reactants than products; not enough products
will shift forward to form more products
68
Q > K
more products than reactants; not enough reactants
will shift backward to form more reactants
69
K = _________ energy ratio
lowest
70
The melting point is the temp. at which...
the solid and liquid phases are in equilibrium
71
the vapor pressure at the boiling point is _____
1
72
boiling point is the temp. at which...
a liquid's equilibrium vapor pressure is equal to the pressure exerted on the liquid by its gaseous surroundings
73
concentration =
molarity
74
For gases to dissolve in a liquid, the sign for ∆Hsolvation must be ____________
negative
75
Polar solvents mix well with...
other polar solvents
76
Polar solvents do not mix well with...
nonpolar solvents
77
What happens to temp. of solution when gas solute is dissolved into a liquid?
increases temp.
78
What happens to temp. of solution when solid solute is dissolved into a liquid?
decreases temp.
79
all covalent solutes will have i =
1
80
all ionic solutes are __________ electrolytes
strong
81
Clausius-Clapeyron Equation
ln (P2/P1) = ∆Hvap/R (1/T1 - 1/T2)
R = 8.314 J/mol x K
82
if you increase entropy, you _________ free energy
lower
83
VPsolution = Xsolvent - VP°solvent
Raoult's Law (Version #1): whenever you have a solute in a liquid solvent. The solute is usually a solid.
84
Raoult's Law (Version #1): whenever you have a solute in a liquid solvent. The solute is usually a solid.
VPsolution = Xsolvent - VP°solvent
85
Raoult's Law (Version #2): whenever you want to determine the change in vapor pressure
∆VP = -Xsolute x VP°solvent
86
Main Raoult's Law equation:
VPsolution = XaVP°a + XbVP°b
87
The mole fraction axes for Xa on Raoult's Plot reads ______ to ______
left to right
88
The mole fraction axes for Xb on Raoult's Plot reads ______ to ______
right to left
89
Colligative properties are properties of a solution that ______ from the pure solvent, and that ___________________
differ, do not depend on what the solute is
90
Colligative properties only depend on the _______________________ in the solution
particle concentration
91
The Four Colligative Properties
Boiling Point Elevation
Freezing Point Depression
Vapor Pressure Lowering
Osmotic Pressure
92
Osmotic Pressure (π) and formula
the pressure needed to maintain equal rates of solvent-to-solution and solution-to-solvent.
π = iMRT
93
higher entropy = ______ free energy = ______ stable
lower, more
94
Kc vs. Kp formula
Kp = Kc(RT)^∆n
95
K is where reaction is most ______
stable
96
Kreverse =
1/Kforward
97
reactant-favored spontaneity?
non-spon
∆G = (+)
98
product-favored spontaneity?
spon
∆G = (-)
99
∆G°
change of free energy for standard reaction when all reactants have converted to products under standard conditions
100
∆G
change of free energy at specific point in reaction
101
∆G° vs. ∆G formula
∆G = ∆G° + RTlnQ
102
K < 1, ∆G =
(+)
103
K > 1, ∆G =
(-)
104
If heat energy is added to an exothermic reaction, the reaction shifts to add some __________
reactants
105
If heat energy is added to an endothermic reaction, the reaction shift to add some __________
products
106
What is the only factor that affects K?
temperature
107
If we decrease the volume of the container of gases, the pressure inside the container will increase. Reaction will move towards the side of the reaction with...
fewer gas molecules
108
If we increase the volume of the container of gases, the pressure inside the container will decrease. Reaction will move towards side of the reaction with...
the greater number of gas molecules
109
For only water, 1 mL =
1 gram
110
combustion equation
fuel + O2 --> CO2 + H20
111
heat of sublimation formula
∆Hfus + ∆Hvap = ∆Hsub
112
In general, the smaller the metal, the larger the...
∆Hvap because atoms can form stronger interactions with neighboring atoms
113
What is Q at t=0?
zero
114
Primary difference between ∆G° and ∆G?
entropy
115
Kc and Kp are the equilibrium constants of gaseous mixtures. However, the difference between the two constants is that Kc is defined by _____________, whereas Kp is defined by the ___________________ of the gasses inside a closed system.
molar concentrations, partial pressures
