CEM 142 Exam 1 Study Guide questions and
answers graded A+
1. Define and give interactions
ex- amples of an
open system 7. What are the prop- erties of
Hydrogen Bonding interactions
2. Define and give
ex- amples of a
closed system
3. Define and give
ex- amples of an
isolated system
4. What are the 7
steps to
determine the
properties fo a
molecular
substance
5. What are the
proper- ties of
LDFs
6. What are the
proper- ties of
Dipole-Dipole
,CEM 142 Exam 1 Study Guide questions and
answers graded A+
In an open system, both 6. Determine what types of IMFs are present
matter and energy can 7. Determine how the molecules might interact
enter or leave ex:
beaker of water -temporary fluctuating dipoles
without a lid -depends on size, surface area, and shape of the molecule
-*for non-polar molecules this is the only force present*
-present in ALL substances
In a closed
system, -present in polar substances (along with LDFs)
only energy -typically stronger than LDF (for molecules of the same size)
can enter or
leave ex:
-present between two molecules but the molecules must first
a closed cooler
contain H bonding covalently to O, N, or F
In an isolated system, the system -because the covalent O-H, N-H, or F-H bond is highly polarized,
cannot exchange either energy or the H
matter with the surroundings
ex: soup poured into an isolated
container and closed because
there is no exchange of heat or
matter
1. draw the lewis structure
2. determine the electron pair
geometry
3. determine the molecular
shape
4. determine the bond polarities
(by ditterence in
electronegativity)
5. Determine molecular polarity
(by adding up the bond polarity
vectors
,CEM 142 Exam 1 Study Guide questions and
answers graded A+
atom has a large partial positive
-the O, N, or F atom (on the other molecule) with the lone pair has a
large partial negative
-H-bonds are extremely strong dipole-dipole interactions
-compounds with H-bonding also have dipole-dipole
8. What does a and LDFs Two electron pairs are involved and it is a
linear bond look
like straight line bond
9. What does a
trigonal planar Trigonal planar has 3 electron bonds involved and makes a triangle
bond look like
There can be either 3 or 4 electron bonds in a bent or angular bond. If
10. What does a bent
or angular bond look there are 3, then the shape looks like a trigonal planar bond but
like with a lone pair on top. The lone pair pushes the other two
bonds down. If there are 4 electron bonds, then the shape is
similar, with the lone pairs at the top, but they are at a slight tilt
away from the midline
11. What does a
This has 4 electron bonds. There is one bond that pushes the other 3
tetrahe- dral bond
down a little bit. Instead of it being like a bent shape, this time the 3
look like
, CEM 142 Exam 1 Study Guide questions and
answers graded A+
other bonds are pushed into
ditterent planes. Basically,
there's one bond on the top, and
then 3 at the bottom kind of like
a tripod
answers graded A+
1. Define and give interactions
ex- amples of an
open system 7. What are the prop- erties of
Hydrogen Bonding interactions
2. Define and give
ex- amples of a
closed system
3. Define and give
ex- amples of an
isolated system
4. What are the 7
steps to
determine the
properties fo a
molecular
substance
5. What are the
proper- ties of
LDFs
6. What are the
proper- ties of
Dipole-Dipole
,CEM 142 Exam 1 Study Guide questions and
answers graded A+
In an open system, both 6. Determine what types of IMFs are present
matter and energy can 7. Determine how the molecules might interact
enter or leave ex:
beaker of water -temporary fluctuating dipoles
without a lid -depends on size, surface area, and shape of the molecule
-*for non-polar molecules this is the only force present*
-present in ALL substances
In a closed
system, -present in polar substances (along with LDFs)
only energy -typically stronger than LDF (for molecules of the same size)
can enter or
leave ex:
-present between two molecules but the molecules must first
a closed cooler
contain H bonding covalently to O, N, or F
In an isolated system, the system -because the covalent O-H, N-H, or F-H bond is highly polarized,
cannot exchange either energy or the H
matter with the surroundings
ex: soup poured into an isolated
container and closed because
there is no exchange of heat or
matter
1. draw the lewis structure
2. determine the electron pair
geometry
3. determine the molecular
shape
4. determine the bond polarities
(by ditterence in
electronegativity)
5. Determine molecular polarity
(by adding up the bond polarity
vectors
,CEM 142 Exam 1 Study Guide questions and
answers graded A+
atom has a large partial positive
-the O, N, or F atom (on the other molecule) with the lone pair has a
large partial negative
-H-bonds are extremely strong dipole-dipole interactions
-compounds with H-bonding also have dipole-dipole
8. What does a and LDFs Two electron pairs are involved and it is a
linear bond look
like straight line bond
9. What does a
trigonal planar Trigonal planar has 3 electron bonds involved and makes a triangle
bond look like
There can be either 3 or 4 electron bonds in a bent or angular bond. If
10. What does a bent
or angular bond look there are 3, then the shape looks like a trigonal planar bond but
like with a lone pair on top. The lone pair pushes the other two
bonds down. If there are 4 electron bonds, then the shape is
similar, with the lone pairs at the top, but they are at a slight tilt
away from the midline
11. What does a
This has 4 electron bonds. There is one bond that pushes the other 3
tetrahe- dral bond
down a little bit. Instead of it being like a bent shape, this time the 3
look like
, CEM 142 Exam 1 Study Guide questions and
answers graded A+
other bonds are pushed into
ditterent planes. Basically,
there's one bond on the top, and
then 3 at the bottom kind of like
a tripod
