Ethane (CH3CH3) and Fluoromethane (CH3F) have the same number
of electrons and are essentially the same size. However, ethane has a
boiling point of 184.5C and fluoromethane has a boiling point of 194.7C.
Which answer best explains this 10 degree difference in boiling point in
terms of the van der Waals forces present.
A. It has nothing to do with van der Waals
B. Both molecules have both dispersion and orientation forces present,
but fluoromethane is a slightly larger molecule
C. Both molecules have dispersion forces, but fluoromethane also has
orientation forces present
D. Both molecules are non-polar, but fluoromethane is a slightly larger
molecule - ANSWER C. Both molecules have dispersion forces, but
fluoromethane also has orientation forces present
Covalent interactions are generally long range (i.e., greater than 10 nm).
True or false - ANSWER False
Hydrogen bonding is predominately found between polar molecules
True or False - ANSWER True
Describe all types of bonding that you would expect to exist in each of
the following compounds: a silicon carbide crystal
A. Predominantly covalent and some ionic
B. Predominantly ionic and some covalent
C. Equally ionic and covalent
D. Ionic only - ANSWER A. Predominantly covalent and some ionic
,Describe all types of bonding that you would expect to exist in each of
the following compounds: potassium fluoride (KF)
A. Predominantly covalent and some ionic
B. Predominantly ionic and some covalent
C. Equally ionic and covalent
D. Ionic only - ANSWER B. Predominantly ionic and some covalent
Describe all types of bonding that you would expect to exist in each of
the following compounds: an alloy composed of 90%Al, 7%Si, 3%Mg
A. ionic, covalent and metallic
B. metallic only
C. metallic and ionic
D. metallic and van der waals - ANSWER D. metallic and van der waals
Describe all types of bonding that you would expect to exist in each of
the following compounds: zirconia (ZrO2)
A. predominantly ionic and some covalent
B. Predominantly covalent and some ionic
C. ionic only
D. covalent only - ANSWER A. predominantly ionic and some covalent
Describe all types of bonding that you would expect to exist in each of
the following compounds: ice
A. predominantly ionic and some covalent
B. van der Waals only
C. predominantly covalent, some ionic and van der Waals
D. predominantly ionic and some van der Waals - ANSWER
predominantly covalent, some ionic and van der Waals
Covalent bonding occurs as a result of columbic attraction and the
transfer of valence electrons. True or False? - ANSWER False
Metallic bonds are different from covalent bonds in that the shared
valence electrons are delocalized. True or False? - ANSWER True
, Aluminum has a face centered cubic (fcc) structure with an atomic radius
of 0.143 nm and an atomic weight of 26.98 g/mol. (a) Calculate the
density of Al from this information. (b) What is the planar density of
atoms in the (110) plane.
A. (a) 1.35 g/L, (b) 6.11 atoms/nm^2
B. (a) 2.71 g/L, (b) 8.64 atoms/nm^2
C. (a) 0.678 g/L, (b) 8.64 atoms/nm^2
D. (a) 2.71 g/L, (b) 6.11 atoms/nm^2 - ANSWER B. (a) 2.71 g/L, (b) 8.64
atoms/nm^2
The density of niobium is 8.58g/cm3. It's atomic mass is 92.91 g/mol and
its structure is bcc. (a) Calculate the lattice parameter and the atomic
radius from this information. (b) What is the planar density of atoms in
the (110) plane.
A. (a) a = 0.330 cm; R = 0.143 cm, (b) 26.0 atoms/nm^2
B. (a) a = 0.330 nm; R = 0.467 nm, (b) 13.0 atoms/nm^2
C. (a) a = 0.330 nm; R = 0.143 nm, (b) 13.0 atoms/nm^2
D. (a) a = 0.330 nm; R = 0.117 nm, (b) 26.0 atoms/nm^2 - ANSWER C.
(a) a = 0.330 nm; R = 0.143 nm, (b) 13.0 atoms/nm^2
The first five peaks of the x-ray diffraction pattern for tungsten, which
has a BCC crystal structure; an x-ray source with a wavelength of
0.1542 nm was used.11. What are the indices (hkl) for the first three
peaks?
A. (110), (111), (200)
B. (111), (200), (220)
C. (100), (110), (111)
D. (110), (200), (211) - ANSWER D. (110), (200), (211)
Long Range Order (LRO) - ANSWER refers to a repeating, or periodic,
structure of atoms. When LRO exists, the material has a crystalline
structure where the building blocks are unit cells. all metals
of electrons and are essentially the same size. However, ethane has a
boiling point of 184.5C and fluoromethane has a boiling point of 194.7C.
Which answer best explains this 10 degree difference in boiling point in
terms of the van der Waals forces present.
A. It has nothing to do with van der Waals
B. Both molecules have both dispersion and orientation forces present,
but fluoromethane is a slightly larger molecule
C. Both molecules have dispersion forces, but fluoromethane also has
orientation forces present
D. Both molecules are non-polar, but fluoromethane is a slightly larger
molecule - ANSWER C. Both molecules have dispersion forces, but
fluoromethane also has orientation forces present
Covalent interactions are generally long range (i.e., greater than 10 nm).
True or false - ANSWER False
Hydrogen bonding is predominately found between polar molecules
True or False - ANSWER True
Describe all types of bonding that you would expect to exist in each of
the following compounds: a silicon carbide crystal
A. Predominantly covalent and some ionic
B. Predominantly ionic and some covalent
C. Equally ionic and covalent
D. Ionic only - ANSWER A. Predominantly covalent and some ionic
,Describe all types of bonding that you would expect to exist in each of
the following compounds: potassium fluoride (KF)
A. Predominantly covalent and some ionic
B. Predominantly ionic and some covalent
C. Equally ionic and covalent
D. Ionic only - ANSWER B. Predominantly ionic and some covalent
Describe all types of bonding that you would expect to exist in each of
the following compounds: an alloy composed of 90%Al, 7%Si, 3%Mg
A. ionic, covalent and metallic
B. metallic only
C. metallic and ionic
D. metallic and van der waals - ANSWER D. metallic and van der waals
Describe all types of bonding that you would expect to exist in each of
the following compounds: zirconia (ZrO2)
A. predominantly ionic and some covalent
B. Predominantly covalent and some ionic
C. ionic only
D. covalent only - ANSWER A. predominantly ionic and some covalent
Describe all types of bonding that you would expect to exist in each of
the following compounds: ice
A. predominantly ionic and some covalent
B. van der Waals only
C. predominantly covalent, some ionic and van der Waals
D. predominantly ionic and some van der Waals - ANSWER
predominantly covalent, some ionic and van der Waals
Covalent bonding occurs as a result of columbic attraction and the
transfer of valence electrons. True or False? - ANSWER False
Metallic bonds are different from covalent bonds in that the shared
valence electrons are delocalized. True or False? - ANSWER True
, Aluminum has a face centered cubic (fcc) structure with an atomic radius
of 0.143 nm and an atomic weight of 26.98 g/mol. (a) Calculate the
density of Al from this information. (b) What is the planar density of
atoms in the (110) plane.
A. (a) 1.35 g/L, (b) 6.11 atoms/nm^2
B. (a) 2.71 g/L, (b) 8.64 atoms/nm^2
C. (a) 0.678 g/L, (b) 8.64 atoms/nm^2
D. (a) 2.71 g/L, (b) 6.11 atoms/nm^2 - ANSWER B. (a) 2.71 g/L, (b) 8.64
atoms/nm^2
The density of niobium is 8.58g/cm3. It's atomic mass is 92.91 g/mol and
its structure is bcc. (a) Calculate the lattice parameter and the atomic
radius from this information. (b) What is the planar density of atoms in
the (110) plane.
A. (a) a = 0.330 cm; R = 0.143 cm, (b) 26.0 atoms/nm^2
B. (a) a = 0.330 nm; R = 0.467 nm, (b) 13.0 atoms/nm^2
C. (a) a = 0.330 nm; R = 0.143 nm, (b) 13.0 atoms/nm^2
D. (a) a = 0.330 nm; R = 0.117 nm, (b) 26.0 atoms/nm^2 - ANSWER C.
(a) a = 0.330 nm; R = 0.143 nm, (b) 13.0 atoms/nm^2
The first five peaks of the x-ray diffraction pattern for tungsten, which
has a BCC crystal structure; an x-ray source with a wavelength of
0.1542 nm was used.11. What are the indices (hkl) for the first three
peaks?
A. (110), (111), (200)
B. (111), (200), (220)
C. (100), (110), (111)
D. (110), (200), (211) - ANSWER D. (110), (200), (211)
Long Range Order (LRO) - ANSWER refers to a repeating, or periodic,
structure of atoms. When LRO exists, the material has a crystalline
structure where the building blocks are unit cells. all metals
