CEM 141 EXAM 3 QUESTIONS WITH
VERIFIED ANSWERS. A+ GRADE
2025/2026.
Change of state from solid -> liquid -> gas ________ energy - ANS requires
energy needed to phase change from solid --> liquid --> gas comes from: - ANS the
surroundings
when phases change from solid --> liquid --> gas, interactions are _______ between molecules -
ANS overcome
change of state from gas --> liquid --> solid ______ energy - ANS releases
what happens to the energy from a phase change from gas --> liquid --> solid? - ANS released
to surroundings
when phases change from gas --> liquid --> solid, interactions are _______ between molecules -
ANS formed
what happens when a substance melts? - ANS the interactions between the particles have to
be overcome -- so that they can remove relative to each other (that's what allows a liquid to
flow)
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,melting and boiling points provide an estimate of: - ANS the strength of the attractive
interactions between particles
which is stronger?? covalent bond/LDF - ANS covalent bond
in a covalent bond, what is formed? - ANS a new molecule
what is a LDF caused by? - ANS fluctuating charge distribution
covalent bonds are the sharing of: - ANS valence electrons
LDF's increase with.... - ANS the size of electron cloud
covalent bonds are caused by: - ANS attraction between electrons of one atom and the
nucleus of another
LDFs are present where??? - ANS between all molecular species
is it hard or easy to predict covalent bond strength? - ANS hard
when are covalent bonds present? - ANS when atomic orbitals interact constructively
covalent bonds are located: - ANS between molecules/networks
LDFs occur between: - ANS separate molecules
diamond has a high/low melting point??? - ANS high
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, graphite has a high/low melting point?? - ANS high
diamond is hard/soft? - ANS hard
graphite is hard/soft? - ANS soft
diamond's physical properties - ANS brittle, translucent
diamond does/does not conduct electricity?? - ANS does not
graphite's physical properties - ANS slippery, shiny, grey
graphite does/does not conduct electricity? - ANS does
in diamond, each carbon forms how many bonds to how many carbons??? - ANS 4 bonds to
4 identical carbons
in diamond, the bonds between carbons arrange themselves towards: - ANS the corners of a
4-sided figure (tetrahedron)
what is the C-C-C bond angle in diamond? - ANS 109°
what model of bonding is used to explain the bonding in carbon? - ANS Valence Bond Theory
Valence Bond Theory - ANS atomic orbitals overlap to form bonds
how are bonds often shown in the valence bond theory? - ANS as "sticks"
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
VERIFIED ANSWERS. A+ GRADE
2025/2026.
Change of state from solid -> liquid -> gas ________ energy - ANS requires
energy needed to phase change from solid --> liquid --> gas comes from: - ANS the
surroundings
when phases change from solid --> liquid --> gas, interactions are _______ between molecules -
ANS overcome
change of state from gas --> liquid --> solid ______ energy - ANS releases
what happens to the energy from a phase change from gas --> liquid --> solid? - ANS released
to surroundings
when phases change from gas --> liquid --> solid, interactions are _______ between molecules -
ANS formed
what happens when a substance melts? - ANS the interactions between the particles have to
be overcome -- so that they can remove relative to each other (that's what allows a liquid to
flow)
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,melting and boiling points provide an estimate of: - ANS the strength of the attractive
interactions between particles
which is stronger?? covalent bond/LDF - ANS covalent bond
in a covalent bond, what is formed? - ANS a new molecule
what is a LDF caused by? - ANS fluctuating charge distribution
covalent bonds are the sharing of: - ANS valence electrons
LDF's increase with.... - ANS the size of electron cloud
covalent bonds are caused by: - ANS attraction between electrons of one atom and the
nucleus of another
LDFs are present where??? - ANS between all molecular species
is it hard or easy to predict covalent bond strength? - ANS hard
when are covalent bonds present? - ANS when atomic orbitals interact constructively
covalent bonds are located: - ANS between molecules/networks
LDFs occur between: - ANS separate molecules
diamond has a high/low melting point??? - ANS high
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, graphite has a high/low melting point?? - ANS high
diamond is hard/soft? - ANS hard
graphite is hard/soft? - ANS soft
diamond's physical properties - ANS brittle, translucent
diamond does/does not conduct electricity?? - ANS does not
graphite's physical properties - ANS slippery, shiny, grey
graphite does/does not conduct electricity? - ANS does
in diamond, each carbon forms how many bonds to how many carbons??? - ANS 4 bonds to
4 identical carbons
in diamond, the bonds between carbons arrange themselves towards: - ANS the corners of a
4-sided figure (tetrahedron)
what is the C-C-C bond angle in diamond? - ANS 109°
what model of bonding is used to explain the bonding in carbon? - ANS Valence Bond Theory
Valence Bond Theory - ANS atomic orbitals overlap to form bonds
how are bonds often shown in the valence bond theory? - ANS as "sticks"
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
