Honors Chemistry
Name: ____________________________________ Date: __________________ Mods: __________
Ch. 11 – Sections 1 & 2 In-Class Notes
11.1 – Molecular Comparison of States of Matter
1) In the boxes below draw the molecular representation of particles for each state of matter
Solid:
Liquid:
very ordered arrangement
particles in fixed positions
very close to one another
ridged crystalline structure
retains its shape & volume
virtually incompressible
condensed phase
does not flow
particles vibrate in place
Gas:
less ordered arrangement
particles are free to move
particles are close together
assumes shape of container
constant volume
virtually incompressible
condensed phase
readily flows
particles move quickly
total disorder of particles
much empty space
particles very far apart
complete freedom of motion
assumes shape of container
variable volume
easily compressed
readily flows
particles move extremely fast
2) State of Matter (at a given temperature and pressure) depends on two quantities:
a. _____________________________________________________:
 KE (energy of motion) is directly proportional to temperature (thermal enenrgy)  the higher
the temp, the _________________ the kinetic energy which means faster moving particles
with weaker forces of attraction between them
 List the 3 states of matter in order of decreasing kinetic energy, with #1 being the highest KE:
#1) _____________________
#2) ____________________
#3) ___________________
b. ________________________________________________________________________:
 Forces of attraction bond particles together
 The ___________________ the attraction, the closer together the particles are to each other
3) How does KE and strength of attraction explain properties of solids, liquids, and gases?
a. Gases: high KE (particles move very fast) means the particles have enough energy of motion
to _____________________ any foces of attraction that would keep them closely bound
together (thus gases _______________________, or spread apart from one another)
b. Liquids: less KE (slower moving) means that the forces of attraction are greater in liquids than
in gases; this greater attraction draws liquid particles closer to one another & the particles move
___________________ but they are still able to flow past one another easily
c. Solids: very little KE (particles only vibrate in place) means that forces of attraction are the
_______________________ within a solid; it is this great attraction which keeps the particles
tightly bound togetehr in ridged crystaline structures
4) Phase Changes –there are two ways to change the state of matter of a substance:
a. Change in ____________________________:
 Increasing the thermal energy of a substance allows it to have a greater kinetic energy (on a
molecular level)
 This means, if heated enough, the _________________ forces which hold the particles of
solids & liquids together can be overcome by KE (vice-versa if gases & liquids are cooled)
 _______________________________: solid  liquid (must be heated to melting point)

_______________________________: liquid  gas (must be heated to boiling point)
b. Change in __________________________ :
 This only affects ___________________ because they are compressible
 Applying pressure will force the particles closer to one another, ___________________ the
strength of attraction between particles
 _______________________________: gas  liquid
11.2 – Intermolecular Forces (IMFs)
1) Why are some substances gases at room temperature while others are liquids or solids?
2) Two categories of bonding/attractive forces:
a. INTRAmolcular Bonding: extremely strong bonding between atoms within a molecule
(repsonsible for holding compounds together)
 Ex) O-H bonds within a water molecule; Na-Cl bonds within sodium chloride
 ____________________ Bonding (M & NM)  atoms held together by attraction from
oppositely charged ions
 ____________________ Bonding (NM & NM) and ____________________ Bonding (M &
M)  atoms held together by the sharing of electrons (e– of one atom are attracted to the
nucleus of another atom, thus holding the 2 atoms together)
 List the 3 types of intramolecular bonds in order of increasing strength, with #1 being the
strongest type of bonding:
#1: ________________________ #2: _____________________ #3: ___________________
b. INTERmolecular Forces (IMFs): attractions between molecules
 Ex) how one H2O molecule interacts with another H2O molecule (or H2O with NaCl)
 IMFs are always ___________________ than intramolecular bonds
 The strength of a substances IMFs greatly impact several physical properties including
___________________ & __________________ point, vapor pressure, and viscosity
 the __________________ the IMFs, the more energy is required to overcome those
forces of atttraction (this means _______________ melting & boiling points)
3) There are 4 types of IMFs  One type of IMF involves charged ions (ion-dipole forces) . The other
three IMFs involve neutral molecules (dipole-dipole forces, London Dispersion Forces, &
hydrogen bonding - these three are collectively referred to as the van der Waals forces).
a. Ion-Dipole Forces (IDFs)
 Attractions between ___________ and ________________ molecules
(Ex) NaCl + H2O
 Since polar molecules are ____________________________, they have partial charges
where one side is partially positive (δ +) and one side is partially negative (δ–).
 The cations are surrounded by the partially ________________________ end of the polar
molecule (vice-cersa for anions).
 IDFs explain how water (or other polar solvents) can interact with and dissolve soluble ionic
compounds
b. Dipole-Dipole Forces (DDFs) - a van der Waals Force
 Attractions between neutral, _________________ molecules
(Ex) PCl3 + PCl3
 ________________ (2 poles) is another way to describe an atom or molecule which has a
separation of charges (half positive, half negative)
 The positive end of one polar molecule is attracted to the negative end of another molecule
near by (and vice versa)
 These forces are only important if the molecules are ________________ to each other
 There are also ______________________ forces that occur when like partial charges come
close to one another.
 For molecules of approximately the same ___________ & ___________, the more polar the
molecule (higher the dipole moment), the stronger the DDFs and the higher the boiling point
c. London Dispersion Forces (LDFs) - a van der Waals Force
 Attractions between __________________ molecules
(Ex) He + He; H2 + H2
 Nonpolar atoms are very _____________________ by nature, therefore no dipole
(separation of charge) typically exists. A dipole, however, can be ___________________…
 Basically, there are three stages to LDF attractions:
 #1) Symmetrical Molecule: electrons are __________________ dispersed around the
nucleus (at this time there is no attraction bewtween atoms or molecules)
 #2) Instantaneous Dipole: brief ________________________ of an atom or molecule
occurs when electrons temporarily (by a freak occurrence) cluster on one side of an atom
or molecule; this causes an instantaneous dipole where it momentarily has weak partial
charges
 #3) Induced Dipole in Neighboring atom: the instanataneous polarization of one atom
causes the electrons in another neighboring atom to shift (thus giving it momentary partial
charges); these two induced dipoles are then attracted to one another
 *** LDFs are present in ___________ molecules, whether they are polar or non polar ***
 The strength of LDFs depends on how easily the electrons in an atom or molecule can be
distorted (the moelcule’s ________________________________)
 The larger the molecule (with a greater molecular weight), the ____________ electrons it
has, the stronger the LDFs, and the _______________ the boiling point of the substance
d. Hydrogen Bonding (H-bonds) - a van der Waals Force
 A special type of dipole-dipole force that occurs between polar molecules which
include hydrogen bonded to ________________, _______________, or ______________
 H-bonds are the _____________________ of the van der Waals forces
 H-bonding arises due to the high ______________________________ of N, O, and F
 When hydrogen is bonded to one of these very EN elements in a molecule, the more EN
element pulls the electron further ______________ from hydrogen, creating partial
charges within the molecule (H is partially positive); this creates a very large EN difference
within the molecule make it extremely ____________________
4) List the 4 type of IMFs in order of increasing strength, with #1 being the strongest forces of
attraction:
#1: _____________________________________________ - strongest
#2: _____________________________________________
#3: _____________________________________________
#4: _____________________________________________ - weakest
5) How does the strength of the IMFs impact properties like the boiling point of the substance?
6) How does the size (molecular weight) of an
atom or molecule impact the strength of IMFs?
7) In the diagram to the right, the
___________________ molecules
are given on the top line while
______________________ molecules
are on the lower line . We can conclude
that the ____________________ the size of
the molecule and the ________________
polar the molecule, the higher the boiling
point.