CEM 141 Exam 3 CORRECT
QUESTIONS & ANSWERS
change of state from solid -> liquid -> gas ________ energy - ANSWERrequires
energy needed to phase change from solid --> liquid --> gas comes from: - ANSWERthe
surroundings
when phases change from solid --> liquid --> gas, interactions are _______ between
molecules - ANSWERovercome
change of state from gas --> liquid --> solid ______ energy - ANSWERreleases
what happens to the energy from a phase change from gas --> liquid --> solid? -
ANSWERreleased to surroundings
when phases change from gas --> liquid --> solid, interactions are _______ between
molecules - ANSWERformed
what happens when a substance melts? - ANSWERthe 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)
melting and boiling points provide an estimate of: - ANSWERthe strength of the
attractive interactions between particles
which is stronger?? covalent bond/LDF - ANSWERcovalent bond
in a covalent bond, what is formed? - ANSWERa new molecule
what is a LDF caused by? - ANSWERfluctuating charge distribution
covalent bonds are the sharing of: - ANSWERvalence electrons
LDF's increase with.... - ANSWERthe size of electron cloud
covalent bonds are caused by: - ANSWERattraction between electrons of one atom and
the nucleus of another
LDFs are present where??? - ANSWERbetween all molecular species
is it hard or easy to predict covalent bond strength? - ANSWERhard
, when are covalent bonds present? - ANSWERwhen atomic orbitals interact
constructively
covalent bonds are located: - ANSWERbetween molecules/networks
LDFs occur between: - ANSWERseparate molecules
diamond has a high/low melting point??? - ANSWERhigh
graphite has a high/low melting point?? - ANSWERhigh
diamond is hard/soft? - ANSWERhard
graphite is hard/soft? - ANSWERsoft
diamond's physical properties - ANSWERbrittle, translucent
diamond does/does not conduct electricity?? - ANSWERdoes not
graphite's physical properties - ANSWERslippery, shiny, grey
graphite does/does not conduct electricity? - ANSWERdoes
in diamond, each carbon forms how many bonds to how many carbons??? - ANSWER4
bonds to 4 identical carbons
in diamond, the bonds between carbons arrange themselves towards: - ANSWERthe
corners of a 4-sided figure (tetrahedron)
what is the C-C-C bond angle in diamond? - ANSWER109°
what model of bonding is used to explain the bonding in carbon? - ANSWERValence
Bond Theory
Valence Bond Theory - ANSWERatomic orbitals overlap to form bonds
how are bonds often shown in the valence bond theory? - ANSWERas "sticks"
in the Molecular Orbital Theory, atomic orbitals combine to form: - ANSWERan equal #
of molecular orbitals
in MO Theory, each orbital can contain up to ____ electrons - ANSWER2
in MO theory, electrons in bonding orbitals (stabilized/destabilized) the system?? -
ANSWERstabilized
QUESTIONS & ANSWERS
change of state from solid -> liquid -> gas ________ energy - ANSWERrequires
energy needed to phase change from solid --> liquid --> gas comes from: - ANSWERthe
surroundings
when phases change from solid --> liquid --> gas, interactions are _______ between
molecules - ANSWERovercome
change of state from gas --> liquid --> solid ______ energy - ANSWERreleases
what happens to the energy from a phase change from gas --> liquid --> solid? -
ANSWERreleased to surroundings
when phases change from gas --> liquid --> solid, interactions are _______ between
molecules - ANSWERformed
what happens when a substance melts? - ANSWERthe 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)
melting and boiling points provide an estimate of: - ANSWERthe strength of the
attractive interactions between particles
which is stronger?? covalent bond/LDF - ANSWERcovalent bond
in a covalent bond, what is formed? - ANSWERa new molecule
what is a LDF caused by? - ANSWERfluctuating charge distribution
covalent bonds are the sharing of: - ANSWERvalence electrons
LDF's increase with.... - ANSWERthe size of electron cloud
covalent bonds are caused by: - ANSWERattraction between electrons of one atom and
the nucleus of another
LDFs are present where??? - ANSWERbetween all molecular species
is it hard or easy to predict covalent bond strength? - ANSWERhard
, when are covalent bonds present? - ANSWERwhen atomic orbitals interact
constructively
covalent bonds are located: - ANSWERbetween molecules/networks
LDFs occur between: - ANSWERseparate molecules
diamond has a high/low melting point??? - ANSWERhigh
graphite has a high/low melting point?? - ANSWERhigh
diamond is hard/soft? - ANSWERhard
graphite is hard/soft? - ANSWERsoft
diamond's physical properties - ANSWERbrittle, translucent
diamond does/does not conduct electricity?? - ANSWERdoes not
graphite's physical properties - ANSWERslippery, shiny, grey
graphite does/does not conduct electricity? - ANSWERdoes
in diamond, each carbon forms how many bonds to how many carbons??? - ANSWER4
bonds to 4 identical carbons
in diamond, the bonds between carbons arrange themselves towards: - ANSWERthe
corners of a 4-sided figure (tetrahedron)
what is the C-C-C bond angle in diamond? - ANSWER109°
what model of bonding is used to explain the bonding in carbon? - ANSWERValence
Bond Theory
Valence Bond Theory - ANSWERatomic orbitals overlap to form bonds
how are bonds often shown in the valence bond theory? - ANSWERas "sticks"
in the Molecular Orbital Theory, atomic orbitals combine to form: - ANSWERan equal #
of molecular orbitals
in MO Theory, each orbital can contain up to ____ electrons - ANSWER2
in MO theory, electrons in bonding orbitals (stabilized/destabilized) the system?? -
ANSWERstabilized
