Intermolecular forces: Solids, Liquids, and Solutions Flashcards
1
Q
Polarizability
What is Polarizability?
A
- Ability to induce another nonpolar molecule to have a momentary dipole between instantaneuous and indused dipole
- Happens with Covalent Compounds
2
Q
IMF Trends
LDF Trends
A
- Increased = Increased size
- Increased = Increased polarizability
- Increased = Greater Charge Separation
3
Q
Dipole-Dipole forces
What are they?
A
- Polar molecules with positive “end” and negative “end” which have a permanent dipole which attracts other dipoles when closer
- Stronger than LDF
4
Q
Important Note!
What to do with LDF on Test
A
- Write full form: London Dispersion Forces
5
Q
Hydrogen bonds
Conditions
A
- H has to be attached to F,O,N
- Other end is also F,O,N with/without H
6
Q
Hydrogen bonds
What are they?
A
- Strong and special d-d
- Have to write both d-d + h-b
- bet H proton and negative side of F,O,N
7
Q
Surface Tension
Definition
A
- Amount of energy required to stretch
- Increased surface of liquid by 1 unit area
- Higher IMFs = Higher ST
8
Q
Surface Tension
Adhesion
A
IMFs between unlike molecules
9
Q
Surface Tension
Cohesion
A
IMFs between like molecules
10
Q
Viscocity
Definition
A
- Measure of a fluid’s resistance to flow
- Increased T = Decreased V
- Increased V = Increased IMFs
- Tangling ==> Increased V
11
Q
H2O
Properties
A
- Excellent Solvent
- High Specific heat
- Ice Density is less than Water because struct for spread out
12
Q
Liquid-Vapor Equilibrium
Vapor Pressure
A
- Partial pressure of liquids once equilbrium is established between gases and liquids
- Book Definition: Gaseous molecules pressure form evap. liquid
13
Q
Liquid-Vapor Equilibrium
Dynamic Equilbrium
A
- Rate of forward process(l–>g) = Rate of backward process(g–>l)
- Constant Pressure
14
Q
Liquid-Vapor Equilibrium
When is Boiling Point?
A
- When Vapor Pressure is equal to External pressure
15
Q
Phase Changes
Critical Point
A
- Temperature that gas cant become a liquid no matter the pressure
16
Q
IMF Trends
How are physical characteristics affected by IMFs?(only writing abt. high)
BP, VP, Viscocity, ST, Cohesive Forces
A
- Higher BP
- Lower VP
- Higher viscocity
- Higher ST
- High Cohesive Forces
17
Q
Hydrogen Bonding
Salicylic Acid
A
- H-Bonding within molecule
18
Q
Chromatography Lab
Rf
A
solute Distance/ Solvent Distance
19
Q
VP Curves
Equation
A
- ln(Pvap1, T1/Pvap2, T2)=(∆Hvap/R)((1/T2)-(1/T1))
20
Q
Alloys
Definition
A
- Solid Soln consisting of 2+ metals or metals with 1 + nm
21
Q
Covalent Network Solids
Definition
A
- Network of covalently-bonded atoms into 2D and 3D network, holding it firmly together
22
Q
Covalent Network Solids
Allotropes
A
- Elements exist in 2 diff formes in same physical state
- Ex) diamond and graphite for carbon
23
Q
Semiconductors
Definitions
A
- Elements that are normally not conductors but are at high Temperatures or when coombined with other elements
24
Q
Semicoductors
N-type
A
- Have an extra electron from bonding which can be used to create a voltage
- Donor Impurities
25
# Semiconductors
P-type
* Have 1 less electron which creates "positive holes" that constatnly shift and allow current to flow through holes
* Acceptor Impurities
26
# Physical Properties of Solns
Solvents
* determine soln's state of matter
* usually majority component
27
# Physical Properties of Solns
Solutes
* Substance dissolbed/dispersed in the solvent
28
# Physical Properties of Solns
Solution Concentration
* Amnt of solute/ amount of solvent/soln
29
# Physical Properties of Solns
Molality(m)
* moles of solute/ kg of solvent
* varies with mass of solvent and is *independent of temperature*
30
# Physical Properties of Solns
Enthalpy of Soln
* Combination of Heat required breaking IMFs of solute and solvent plus the heat released for letting them mix
31
# Physical Property of Solutions
Non-Ideal Solutions
* Not additive solutions(adding two solutions doesn't result in a solutions with both that is not equal than combined amount: Ex) 50mL +50mL≠100mL)
* Happens due to unequal IMFS
* example of *Ideal Mixture* = Benzene and Methylbenzene
32
# Physical Properties of Solutions
How Heat of Solution impacts ideality
* If = 0, Ideal
* If < 0, stronger solute-solvent forces; exothermic
* If > 0, weaker solute-solvent forces; endothermic
33
# Formation of a Saturated Solution
What is a Saturated Solution
* Maximum amount of solid or gas allowed in a liquid with constant Temperature
34
# Formation of Saturated Solution
How temperature affects saturation
* Increased ==> Increased in solids
* Opposite in gases
35
# Formation of Saturated Solution
Henry's Law
* Increased Solubility = Increased Pressure
* s = P * k
36
# Formation of Saturated Solution
K in Henry's Law
* Units: mg[gas]/100g[H2O]/atm
37
# Colligative vs Noncolligative Properties
What are Colligative Properties?
* Physical Properties that depends only on concentration of solute particles, not their identity
* Decreased solvent vapor pressure, Freezing Point Depression, Boiling Point Elevation
38
# Colligative vs Noncolligative Properties
Examples of Noncolligative Properties
* Color, odor, etc.
39
# Volatile Solvents
What if solute is non-volatile?
* Lower solvent volatility because less on surface
* **Raoult's Law:** Vapor Psolv = Xsolv ·P°solv
40
# Volatile Solvents
What if solute is volatile?
* Have to consider both Vapor Pressures
* Pressure[Tot] = P[solvent A] + P[solvent B]
= (XsolvA · P°solvA) + (XsolvB · P°solvB)
41
# Fractional Distillation
How does Fractional Distillation work?
1. Boil 2 liquids
2. Lower Boiling Point will boil out
3. Rise to the condenser
4. distillate
* Example: Water(50mL) + Ethanol(50mL) = mixture (< 100mL)
* Distillation = 50 mL each again
