1
Q
What are the 4 traits of a polar molecule?
A
- Electrons are shared unevenly
- Electronegativity difference greater than .5
- Hydrophilic (love water)
- Hydrogen on the FON
2
Q
What are the 5 traits of a non polar molecule?
A
- Electrons are shared evenly
- Electronegativity difference less than .5
- Hydrophobic (fear water)
- Only carbon and hydrogen
- Symmetrical molecules
3
Q
Which molecular geometry shapes are always polar?
A
Bent
Trigonal pyramidal
Square pyramidal
Seesaw
T-shape
4
Q
When given the drawing of a molecule, what are two key things to look for to determine if it is polar?
A
- different terminal atoms
- lone pair electrons on the central atom
5
Q
Which IMF is the weakest?
A
LDF
6
Q
Which IMF is only present in mixtures?
A
Dipole-induced dipole
7
Q
Which IMF is only present in polar substances?
A
Dipole-dipole
8
Q
What is true of hydrogen bonds?
A
Occurs when an H atom is on the FON
Special type of dipole-dipole force
9
Q
What is true of an ion-dipole force?
A
- Ionic compounds dissolves into a polar solvent
- Any ion interacts with a polar molecule
10
Q
Which IMF is present in all molecules?
A
LDF
11
Q
If you have 2 non polar molecules, which type of IMF will you almost certainly have?
A
LDF
12
Q
What is the relationship between temperature and kinetic energy?
A
As you increase temperature, you increase KE
13
Q
What is the relationship between polarity and temperature required to boil the liquid?
A
As you increase polarity, the temperature required will increase
14
Q
What are the four factors that increase LDF strength?
A
- Increase polarizability
- Increase atomic / molecular size
- Increase molecular weight
- Increase surface area
15
Q
What are the factors that increase the strength of a dipole-induced dipole force?
A
- Increase molar mass of the non polar molecule
- Increase strength of the dipole on the polar molecule
16
Q
What is true of dipole forces and LDFs when comparing substance with molecular sizes that are relatively similar?
A
Dipole forces are more significant than LDFS
17
Q
What is true of dipole forces and LDFs when comparing substance with molecular sizes that are widely different?
A
LDFs are usually more significant than dipole forces
18
Q
What is the order of increasing strength of IMFs?
A
LDF
Dipole-induced dipole
Dipole-dipole
Hydrogen bonding
Ion-dipole
19
Q
What does the shape of the meniscus in a container depend on?
A
The balance between cohesive and adhesive forces
20
Q
What is true of a convex meniscus?
A
- Curves upwards/outwards
- Cohesive forces > adhesive forces
21
Q
What is true of a concave meniscus?
A
- Curves downwards/inwards
- Adhesive forces > cohesive forces
22
Q
Define cohesive force
A
- Attraction between molecules of the same substance
- Strong cohesive forces make drops “bead up”
23
Q
Define adhesive force
A
- Attraction between molecules of different substances
- Strong adhesive forces make liquids spread out on a surface
24
Q
Define viscocity
A
- The resistance of a liquid to flow
- Harder to move = greater viscosity
25
What four factors increase viscosity?
1. Increase the strength of IMF
2. Decrease the temperature
3. Increase molar mass
4. Molecules get more spherical/shorter
26
Define surface tension
The amount of energy (or work) required to increase the surface area of a liquid
27
What two factors increase surface tension?
1. Increase IMF strength
2. Decease temperature
28
Describe the relationship between vapor pressure and binding forces
As you increase vapor pressure, binding forces are weaker
29
If there are only carbons and hydrogens present, is the molecule polar or non polar?
Non polar which means only LDF can exist
30
What two factors increase vapor pressure?
1. Decerase strength of IMF
2. Increase temperature
31
Vapor pressure _____ change with the volume of a container
doesn't
32
What is the relationship between vapor pressure and IMFs?
As you increase IMF strength, you decrease vapor pressure
33
Define normal boiling point
The temperature at which the vapor pressure of a liquid is 760 torr or 1 atm
34
What is the relationship between boiling point and IMF strength?
As you increase IMF strength, you increase boiling point
35
What is the relationship between IMFs and surface tension?
As you increase the strength of the IMF, you increase surface tension
36
What is the relationship between vapor pressure and enthalpy of vaporization?
Larger vapor pressure = smaller enthalpy of vaporization
37
Define enthalpy of vaporization
The energy required to vaporize 1 mole of a liquid at a pressure of 1 am
38
What happens when equilibrium is achieved with a vapor?
The rate at which a gas converts to solid is balanced with the reverse process
39
What is the relationship between vapor pressure and temperature?
As vapor pressure decreases, temperature decreases
40
Volatile vs. nonvolatile
Volatile liquids evaporate easily
Nonvolatile liquids do not
41
Define triple point
Temperature and pressure at which all three states of matter exist
42
Define critical point
Temperature and pressure at which the vapor pressure curve ends
43
Differentiate between crystalline solids and amorphorous solids
Crystalline= arranged in a long-range order/repeating pattern
Amorphous= disordered
44
Define a simple cubit unit cell
A cube with one atom at each corner
45
How many atoms are present in a simple cubic unit cell?
1 atom per cell
46
What is the equation for the edge length of a simple cubic unit cell?
2r
47
Define body-centered cubic unit cell
One atom in each corner and one in the center
48
How many unit cells are in a body-center cubic unit cell
2 atoms per unit cell
49
What is the equation for a body-centered cubic unit cell?
4r/sq root 3
50
Define face-centered cubic unit cell
One atom at each corner and several in the center
51
How many atoms are in a face-center cubic unit cell?
4 atoms per cell
52
What is the equation for a face-centered cubic unit cell?
2 sq root 2r
53
What is the coordination number for a simple cubic unit cell?
6
54
What is the coordination number for a body cubic unit cell?
8
55
What is the coordination number for a face-centered cubic unit cell?
12
56
Define molecular solids
- Lattice sites are occupied by molecules
- Molecules have strong covalent bonds but weak IMFs
57
Define ionic solids
- Lattice sites are occupied by ions
- Oppositely charged ions
58
What are the four properties of ionic solids?
1. Very high melting point
2. Hard and brittle
3. Low conductivity as a solid
4. High conductivity as a liquid
59
Define electron sea model
Positively charged atomic metal nuclei stays still while a sea of delocalized electrons are shared
60
What are the three properties of metallic solids?
1. Very good conductors of heat and electricity
2. Malleable and ductile
3. Variable hardness and melting points
61
What are the four network covalent bonds?
C(diamond)
C(graphite)
SiO2
SiC
62
What are the three properties of network covalent bonds?
1. Very high melting points
2. Harder than metallic solids
3. Not effective conductors
63
What is true about the covalent bonds in molecular solids vs covalent-network solids?
The molecules in molecular solids have weaker covalent bonds than covalent-network solids
64
What is true about IMFs in molecular solids compared to covalent-bonds?
The molecules in molecular solids are held together by weak intermolecular interactions
65
Order the types of solids in order of increasing melting points and give a description of why
1. Molecular solids are held together by LDFs which are the weakest IMF
2. Metallic solids are held together by a sea of electrons
3. Ionic solids are held together in a lattice which has a strong electrostatic force
4. Covalent network solids are covalent bonds held in a giant 3D network
66
What is the relationship between melting point and lattice energy?
As you increase melting point, you increase lattice energy
67
Why are metallic solids considered to have a wide range of melting points?
Because they cover a wide range of bond strength
68
Define ion-dipole forces
Ion-dipole forces occur between an ion and the positive or negative end of a polar molecular
69
Would a nonpolar or polar molecule have the higher boiling point?
Polar
70
Which properties of liquids are determined by IMFs?
Vapor pressure, boiling point, surface tension, viscosity
71
Define sublimation
Solid to gas
72
Define deposition
Gas to solid
73
Define boiling
Liquid to gas
74
Define melting
Solid to liquid
75
Define vaporization
Liquid to gas
76
Define condensation
Gas to liquid
77
If a phase diagram has low temp and high pressure, it is a
solid
78
If a phase diagram has moderate temp and moderate pressure, it is likely a
liquid
79
If a phase diagram has high temp and low pressure, it is likely a
gas
80
Define triple point
The temperature and pressure where all three states of matter exist
81
Define critical point
The temperature and pressure where the vapor pressure curve ends
82
Define supercritical fluid
Past the critical point, the liquid and gas phases are indistinguishable from each other
83
What are the three things to know about the phase diagram of water?
1. Water is less dense as a solid than a liquid
2. Water expands when it freezes
3. Solid molecules are further apart than as a liquid
84
With heating curves, if the phase is the same (straight line) which equation do you us?
q=mcAt
85
With heating curves, if the phase is changing (elevating line) which equation do you use?
q= nAH
86
Define average rate
Concentration of a reactant/product over time
87
Define differential rate law
Relationship between reaction rate and concentration of reactants
88
What is the format for differential rate law?
Rate = k[A]^n
89
What is the relationship between concentration and reaction rate
Greater concentration = higher reaction rate
90
What is the relationship between the order of the reaction and the rate law
The order becomes the exponent
91
Define integrated rate law
Concentration and time
92
What are the units for a zero order integrated rate law?
M/s
93
What are the units for a first order integrated rate law?
s⁻¹
94
What are the units for a second order integrated rate law?
M⁻¹s⁻¹
95
What is true of a zero order integrated rate law?
The rate is proportional to a constant
96
What is the zero order integrated rate law equation?
[A] = -kt + [A]0
97
What is true of a first order integrated rate law?
The rate is proportional to the concentration of A
98
What is the first order integrated rate law equation?
ln [A]t / [A]0 = -kt
99
What is true of a second order integrated rate law?
The rate is proportional to [A]^2
100
What is the second order integrated rate law equation?
1/[A] = kt + 1/[A]0
101
What are the four types of solids?
Molecular, network, metallic, and ionic
102
What are molecular solids?
Molecules
103
What IMFs are molecular solids held together by?
Hydrogen bonds, dipole-dipole, and LDF
104
What are the three main properties of molecular solids?
- Low to medium melting and boiling points
- Poor electricity conductivity
- Some are gases at room temp
105
H2 is an example of what type of solid?
Molecular
106
What are network solids?
Held together by covalent bonds
107
What are the four types of network covalent bonds that we need to know?
C(diamond)
C(graphite)
SiO2
SiC
108
What are the three properties of network covalent solids?
- Very high melting and boiling points
- Harder than metallic solids
- Mostly poor conductors
109
What are ionic solids?
Cations and anions held together by ionic bonds
110
What are the five properties of ionic solids?
- Hard and brittle
- High melting points
- Poor conductor as a solid
- Good cconductor as a liquid
- Soluble in water
111
What are metallic solids?
Made of metal cations held together by metallic bonds
112
What are the three properties of metallic solids?
- Malleable and ductile
- Good electricity and head conductivity
- Wide range of melting points
113
What is the relationship between lattice energy and melting/boiling point?
Higher lattice energy = higher melting/boiling point
114
What is lattice energy?
Energy required to convert one mole of an ionic solid into is gaseous ions
115
What is the relationship between the size of an ion and lattice energy?
As the size of an ion increases, lattice energy of the ion decreases
116
What is the relationship between the charge of an ion and lattice energy?
As the charge of an ion increases, the lattice energy increases
117
What is the trend of lattice energy on the periodic table?
Lattice energy increases across the periodic table, and decreases down the periodic table
118
When determining which substance has the higher lattice energy, you want to look for which one:
Has the higher charge and smaller size
119
What is true about temperature during a phase change?
Temperature remains constant during a phase change
120
What is true about the energy and proximity of molecules in fusion?
Less energy, molecules stay close
121
What is true about the energy and proximity of molecules in vaporization?
More energy, molecules are far aprt
122
Draw a heating/cooling curve diagram
123
During fusion/freezing, what is at equilibrium?
Solid and liquid
124
During deposition/sublimation, what is at equilibrium?
Solid and gas
125
During evaporation/condensation, what is at equilibrium?
Liquid and gas
126
What does differential rate law determine?
The reaction order
127
What does integrated rate law determine?
Half-life
128
What is the focus for differential rate law?
How rate depends on concentration
129
What is the focus for integrated rate law?
How [A] decreases over time
130
When looking at a graph, how do you find the normal boiling point?
Find the temp at 1 atm
general chemistry 2
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