Chem/Phys Flashcards
(213 cards)
Atomic Weight
The weighted average of the masses of the naturally occurring isotopes of an element, in amu per molecule or grams per mole
Mole
A unit used to count particles; represented by Avogadro’s number 6.022 x 10^23 particles
mass of sample/molar mass
Also the amount of substance that contains the same number of particles as a 12.00g sample of C12.
Isotopes
For a given element, multiple species of atoms with the same number of protons but different numbers of neutrons
Planck’s quantum theory
Energy emitted as electro-magnetic radiation from matter exists in discrete bundles called quanta
Bohr’s Model of H Atom
Energy of electron = E = (2.18 * 10^-18 J/e-)/n^2
EM energy of photons = E = hc/wavelength
(h = 6.626 x 10^-34 J/s)
Balmer series vs Lyman series
Group of hydrogen emission lines corresponding to transitions from upper levels n > 2 VS Group of hydrogen emission lines corresponding to upper levels n > 1 to n = 1
Absorption spectra
Characteristic energy bands where electrons absorb energy
Heisenberg Uncertainty Principle
Impossible to know the location and momentum of an electron at the same time
Quantum numbers
Principle (n) - the larger the integer value, the higher the energy level and radius of the electrons orbit; max # e- in energy level n = 2n^2
Azimuthal (l) - Subshells; four, corresponding to I = 0,1,2,3 are s, p, d, f; max # e- within subshell = 4l + 2
Magnetic (ml) - orbital within a subshell where highly likely to find electron; between 1 and -1
Spin (ms) - spin of a particle or intrinsic angular momentum; +1/2 or -1/2
Hund’s Rule
Within a given subshell, orbitals are filled such that there are a maximum number of half filled orbitals with parallel spins
Valence electrons
Electrons of an atom that are in its outer energy shell and available for bonding
Coordination Compounds
Lewis acid-base adduct with a cation bonded to at least one electron pair donor (including H2O); Donor molecules are called ligands and use coordinate covalent bonds.
Chelation
When the central cation in a coordination compound is bound to the same ligand multiple times
Hydrogen bonding
The partial positive charge of the hydrogen atom interacts with the partial negative charge located on the electronegative atoms (F, O, N) of nearby molecules
Dipole-dipole Interactions
Polar molecules orient themselves such that the positive region of one molecule is close to the negative region of another molecule.
Dispersion forces
The bonding electrons in covalent bonds may appear to be equally shared, but at any particular point in time they will be located randomly throughout the orbital, permitting the unequal sharing of electrons and leading to transient polarization and counterpolarization of the electron clouds of neighboring molecules
Units for rate constant?
zero-order - M/s
first-order - s^-1
second-order - M^-1s^-1
third-order - M^-2s^-1
Combustion reaction
A fuel, such as a hydrocarbon, is reacted with an oxidant, such as oxygen, to produce an oxide and water
Combination reaction
Two or more reactants form one product
Decomposition reaction
A compound breaks down into two or more substances, usually as a result of heating or electrolysis
Single-displacement reaction
An atom (or ion) of one compound is replaced by an atom of another element
Double displacement reaction
Also called metathesis reactions; elements from two different compounds displace each other to form two new compounds
Net ionic equation
Written showing only species that actually participate in the reaction
Neutralization reaction
A specific type of double-displacement reaction that occurs when an acid reacts with a base to produce a solution of a salt and usually water