MSU CEM 141 Final Exam Prep Newest Actual
Exam With Complete Questions And Correct
Detailed Answers (Verified Answers) |Already
Graded A+ Michigan State University
scientific theory
A well-tested concept that explains a wide range of observations (explains why).
changes with time. Explains the underlying cause of a range of phenomena
Frequency (V)
The number of wavefronts per second. Highest: x-ray
Bonding Orbitals
Atomic orbitals combine constructively to form a molecular orbital of lower
energy, stabilizing, in phase, creates sigma orbital.
In He-He both boding and antibonding MOs are occupied. Because their
energies are equal and opposite _.
He Doesn't Bond.
,H Bond
In H-H only the bonding MO is occupied, leading to net stabilization of the
interaction
Breaking bond: enough energy has to be added to raise an electron to the
antibonding orbital.
Why are metals (diamond, graphite) shiny?
Emits and Absorbs Photons.
Band Theory
Determining between metals, semi conductors and insulators based on energy
gap between the valence band (bonding MOs) and conduction band
(antibonding MOs)
Metals
According to band theory, valence band overlaps with conduction band.
Semiconductors
According to band theory, there's a small gap between valence band and
conduction band.
,Insulators
According to band theory, there's a large gap between the valence band and
conduction band.
Solid to Liquid to Gas
Phase change: requires energy, energy comes from the surroundings, attractions
are overcome between molecules.
Gas to Liquid to Solid
Phase change: releases energy, energy released to surroundings, attractions
formed between molecules.
Gas
LDF and covalent bonds are overcome by energy.
Melting
LDF is overcome by energy.
LDF
Bond that is relatively weak, caused by fluctuating charge distribution, increases
with size of electron cloud (predictable), present between all molecular species,
between separate molecules.
, Diamond
Allotrope of Carbon with high melting point, hard, brittle, translucent, does not
conduct electricity, insulator
C-C-C bond angle is 109.
Graphite
Allotrope of Carbon with high melting point, soft, slippery, grey, shiny, conducts
electricity.
Valance Bond Theory
Theory that atomic orbitals overlap to form a bond, the greater the overlap the
stronger the bond. Each bond is made up of two electrons, electrons are
localized in the bonds.
Hybridized bonds
One s and three p orbitals combine to create sp3 orbitals, create strong sigma
bonds (like in diamonds) between atoms.
Pi Bond
Covalent bond formed by overlapping p orbitals, weaker than a sigma bond.
Sigma Bond
Covalent bond formed by overlapping atomic orbitals, stronger than pi bond.
Exam With Complete Questions And Correct
Detailed Answers (Verified Answers) |Already
Graded A+ Michigan State University
scientific theory
A well-tested concept that explains a wide range of observations (explains why).
changes with time. Explains the underlying cause of a range of phenomena
Frequency (V)
The number of wavefronts per second. Highest: x-ray
Bonding Orbitals
Atomic orbitals combine constructively to form a molecular orbital of lower
energy, stabilizing, in phase, creates sigma orbital.
In He-He both boding and antibonding MOs are occupied. Because their
energies are equal and opposite _.
He Doesn't Bond.
,H Bond
In H-H only the bonding MO is occupied, leading to net stabilization of the
interaction
Breaking bond: enough energy has to be added to raise an electron to the
antibonding orbital.
Why are metals (diamond, graphite) shiny?
Emits and Absorbs Photons.
Band Theory
Determining between metals, semi conductors and insulators based on energy
gap between the valence band (bonding MOs) and conduction band
(antibonding MOs)
Metals
According to band theory, valence band overlaps with conduction band.
Semiconductors
According to band theory, there's a small gap between valence band and
conduction band.
,Insulators
According to band theory, there's a large gap between the valence band and
conduction band.
Solid to Liquid to Gas
Phase change: requires energy, energy comes from the surroundings, attractions
are overcome between molecules.
Gas to Liquid to Solid
Phase change: releases energy, energy released to surroundings, attractions
formed between molecules.
Gas
LDF and covalent bonds are overcome by energy.
Melting
LDF is overcome by energy.
LDF
Bond that is relatively weak, caused by fluctuating charge distribution, increases
with size of electron cloud (predictable), present between all molecular species,
between separate molecules.
, Diamond
Allotrope of Carbon with high melting point, hard, brittle, translucent, does not
conduct electricity, insulator
C-C-C bond angle is 109.
Graphite
Allotrope of Carbon with high melting point, soft, slippery, grey, shiny, conducts
electricity.
Valance Bond Theory
Theory that atomic orbitals overlap to form a bond, the greater the overlap the
stronger the bond. Each bond is made up of two electrons, electrons are
localized in the bonds.
Hybridized bonds
One s and three p orbitals combine to create sp3 orbitals, create strong sigma
bonds (like in diamonds) between atoms.
Pi Bond
Covalent bond formed by overlapping p orbitals, weaker than a sigma bond.
Sigma Bond
Covalent bond formed by overlapping atomic orbitals, stronger than pi bond.
