Chemistry Exam 2
Formal Charge formula
Fc= # val e⁻ - ( # nonbonding e⁻ + 1/2(#bonding e))
Iron (iii) bromide
FeBr₃
Hydrogen carbonate or bicarbonate
HCO₃⁻
chloric acid
HClO₃
Hydrogen phosphate
HPO₄²⁻
Hydrogen sulfite or bisulfite
HSO₃⁻
Dihydrogen phosphate
H₂PO₄⁻
pm to nm
pm ∙ 1nm/1000pm
sp3d2 hybrid orbitals
six equivalent hybrid orbitals pointing towards the vertices of an octahedron that form by mixing one s orbital, three p orbitals, and two d orbitals from the same shell.
NaCH₃COO
sodium acetate
Energy levels of orbitals
sp3<sp2<sp
antibonding orbital
term in MO theory describing regions of electron density in a molecule that destabilize the molecule because they do not increase the electron density between nuclear centers.
bonding orbital
term in MO theory describing regions of increased electron density between nuclear centers that serve to hold atoms together in molecules.
valence
the capacity of the atoms of an element to form chemical bonds
sphere of hydration
the cluster of water molecules surrounding an ion in an aqueous solution.
solvent
the component of a solution that is present in the largest number of moles.
bond length
the distance between the nuclear centers of two atoms joined together in a bond
What is Eel inversely proportional to?
the distance between the two particles
electrostatic potential energy (Eel) (coulombic attraction)
the energy a charged particle has because of its position relative to another charged particle
lattice energy (U)
the energy released when 1 mole of an ionic compound forms from its free ions in the gas phase
solubility
the maximum quantity of a substance that can dissolve in a given volume of solution.
viscosity
the measure of the resistance to flow of a fluid.
Phosphate
PO₄³⁻
KNO₂
Potassium nitrite
Thiocyanate
SCN⁻
Sulfite
SO₃²⁻
Sulfate
SO₄²⁻
Bonding in metals is best described as ______ a. a transfer of electrons between many atoms. b. a network of covalent bonds. c. a sea of pooled electrons. d. highly directional and localized. e. completely electrostatic
c a sea of pooled electrons.
organic compounds
compounds that contain carbon, hydrogen, and sometimes toher elements including oxygen, nitrogen, sulfur, and a halogen.
chiral
describes a molecule that is not superimposable on its mirror image.
diamagnetic
describes a substance with no unpaired electrons that is weakly repelled by a magnetic field.
paramagnetic
describes a substance with unpaired electrons that is attracted to a magnetic field.
Coulomb's law states that the interaction energy between ions depends ______ a. only on the ionic charges. b. only on the distance between the ions. c. directly on both the ionic charges and the distance between the ions. d. on the temperature. e. directly on the ionic charges and inversely on the distance between the ions.
e. directly on the ionic charges and inversely on the distance between the ions.
sp3d orbitals
five equivalent hybrid orbitals with lobes pointing toward the vertices of a trigonal bipyramid that form by mixing one s orbital, three p orbitals, and one d orbital from the same shell.
molecular orbital diagram
in MO theory, an energy-level diagram showing the relative energies and electron occupancy of the molecular orbitals for a molecule.
pi molecular orbital
in MO theory, an orbital formed by the mixing of atomic orbitals oriented above and below, or in front of and behind, the bonding axis; electrons in pi orbitals form pi bonds.
sigma molecular orbital
in MO theory, the orbital that results in the highest electron density between the two bonded atoms.
hybrid atomic orbital
in valence bond theory, one of a set of equivalent orbitals about an atom created when specific atomic orbitals are mixed.
hybridization
in valence bond theory, the mixing of atomic orbitals to generate new sets of orbitals that then are available to form covalent bonds with other atoms.
stereoisomerism
isomerism created by differences in the orientations of the bonds between atoms in molecules.
miscible
liquids that are mutually soluble in any proportion
molecular recognition
the process by which molecules interact with other molecules to produce a biological effect.
What is Eel directly proportional to?
the product of the charges of the particles
polarizability
the relative ease with which the electron cloud in a molecule, ion, or atom can be distorted, inducing a temporary dipole
temporary dipole
the separation of charge produced in an atom or molecule by a momentary uneven distribution of electrons; also called induced dipole.
hydrogen bond
the strongest dipole-dipole interaction, which occurs between a hydrogen atom bonded to a N, O, or F atom and another N, O, or F atom.
sp2 hybrid orbitals
tthree hybrid orbitals in a trigonal planar orientation formed by mixing one s and two p orbitals.
sp hybrid orbitals
two hybrid orbitals on opposite sides of the hybridized atom formed by mixing one s and one p orbital.
Calculate the electrostatic potential energy in J of the interaction of one magnesium ion (86 pm radius) and one bromide ion (182 pm radius) in magnesium bromide.
-1.7x10⁻¹⁸J
Estimate the enthalpy of reaction, H⁰, for 2H₂(g) + O₂(g)→2H₂O(g) using bond energies. Bond ------------ 0=0 O-H H-H Energy(kj/mole) 498 463 436
-482 kJ/mol
Rules of MO theory
1. The number of molecular orbitals equals the number of atomic orbitals used to create them. 2. Atomic orbitals with similar energy and orientation mix more effectively than do those that have different energies and orientations. 3. Better mixing leads to a larger energy difference between bonding and antibonding orbitals and thus greater stabilization of the bonding MOs. 4. A molecular orbital can accomodate a maximum of two electsons; two electrons in the same MO have opposite spins. 5. Electrons in ground-state molecules occupy the lowest energy molecular orbitals available, following the aufbau principle and Hund's rule.
Cr₂S₃
Chromium (iii) sulfide
Which of the following will have the largest ( most negative) lattice energy? a. NaF b. NaCl c. NaBr d. NaI e. CsCl
A. NaF
Hypochlorite
ClO⁻
Chlorite
ClO₂⁻
Chlorate
ClO₃⁻
Which of the following will require the greatest energy input to separate the ions? a. MgI₂ b. MgF₂ c. MgCl₂ d MgBr₂ e NaCl
B MgF₂
Acetate
CH₃COO⁻
Cyanide
CN⁻
Carbonate
CO₃²⁻
Ca₃(PO₄)₂
Calicum Phosphate
Perchlorate
ClO₄⁻
Chromate
CrO₄²⁻
Dichromate
Cr₂O₇²⁻
Which of the following statements regarding ionic compound is zero? a. The net charge of an ionic compound is zero. b. Oppositely charged ions collect together in part because isolated ions are not stable. c. The energy associated with an ionic bond is a form of electrostatic potential energy d. Ions are held together by shared pairs of electrons e. Oppositely charged ions arrange themselves to minimize repulsions an maximize attractions.
D. Ions are held together by shared pairs of electrons
Eel=
Eel=2.31x10⁻¹⁹J ∙nm (Q¹-Q₂)/d
Permanganate
MnO₄⁻
Draw the Lewis structure for the ion, OCN-. Show all relevant resonance structures and circle the best one based on formal charges.
N=C-O O=C=N O(triple bond)- C-N ( N-C triple bond) the first one is the best
Ammonium
NH₄⁺
Nitrite
NO₂⁻
Nitrate
NO₃⁻
dinitrogen pentoxide
N₂O₅
Azide
N₃⁻
Hydroxide
OH⁻
Disulfide
S₂²⁻
isomer
one of a group of compounds having the same chemical formula but different molecular structures
enantiomer
one of a pair of optical isomers of a compound.
Draw the Lewis structure for MgF₂
[Mg]²⁺[F]¹⁻[F]¹⁻ and draw full electrons pairs for the two fluorine
covalent bond
a bond created by two atoms sharing one or more pairs of electrons
molecular orbital (MO) theory
a bonding theory based on the mixing of atomic orbitals of similar shapes and energies to form molecular orbitals that belong to the molecule as a whole.molecular orbital a region of characteristic shape and energy where electrons in a molecule are located.
pi bond
a covalent bond in which electron density is greatest above and below the bonding axis.
sigma bond
a covalent bond in which the highest electron density lies between the two atoms along the bond axis.
aromatic compound
a cyclic, planar compound with delocalized pi electrons above and below the plane of the molecule.
carbonyl group
a functional group that consists of a carbon atom with a double bond to an oxygen atom.
hydroxyl group
a functional group that consists of an oxygen atom with a single bond to a hydrogen atom.
alkane
a hydrocarbon in which each carbon atom is bonded to four other atoms.
dipole moment
a measure of the degree to which a molecule aligns itself in an applied electrical field; a quantitative expression of the polarity of a molecule.
valence bond theory
a quantum mechanics-based theory of bonding that assumes covalent bonds form when half-filled orbitals on different atoms overlap or occupy the same region in space.
racemic mixture
a sample containing equal amounts of both enantiomers of a compound.
sp3 hybridization
a set of four hybrid orbitals with a tetrahedral orientation produced by mixing one s and three p atomic orbitals.
overlap
a term in valence bond theory describing bonds arising from two orbitals on different atoms that occupy the same region of space.
dipole-dipole interactions
an attraction between regions of polar molecules that have partial charges of opposite sign
ion-dipole interaction
an attractive force between an ion and a molecule that has a permanent dipole.
London dispersion force
an intermolecular force between nonpolar molecules caused by the presence of temporary dipoles in the molecules.
crystal lattice
an ordered three-dimensional array of particles (atoms, ions, or molecules)
alcohol
an organic compound whose molecular structure includes a hydroxyl group bonded to a carbon atom that is not bonded to any other functional group(s).
hydrocarbon
an organic compound whose molecules contain only carbon and hydrogen atoms.
solute
any component in a solution other than the solvent. A solution may contain one or more solutes.
Which of the following is the shortest bond? The number in parentheses is the bond energy. a. c-c (248 kj/mol) b. C-F (453 kj/mol) cC-H (411 kj/mol)
b. C-F (453 kj/mol)
constitutional isomer
one of a set of compounds with the same molecular formula but different connections between the atoms in their molecules; also called structural isomers.
