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34 Cards in this Set
- Front
- Back
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quantum mechanics
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n = shell
l = subshell; 0->n-1 ml = orbital; -l->l; 2l+1 orbitals in subshell ms = spin; -1/2->1/2 |
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periodic trends
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atomic radius: increases going down and decreases left to right
electronegativity: how strong atom holds unto electrons in chemical bond; increases left to right and decreases going down ionization energy: energy required to completely remove electron from gaseous atom or ion; trend follows EN electron affinity: energy release when gaseous atom or ion gains an electron |
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group B elements
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-transition elements
-partly filled or filled d subshells -form coordination complexes that are highly colored -inner transition elements are lathanide and actinide series that have partly filled or filled subshells |
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types of bonds
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-ionic bonds occur between metals and nonmetals with large EN differences
-covalent bonds occur between nonmetals and involves the sharing of electrons -polar covalent bonds occur between atoms with different EN and produces a molecule with partial ionic character -nonpolar covalent occurs between atoms with the same EN and is found in diatomic molecules |
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intermolecular forces
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ion-dipole: between polar and ionic molecules; ex: NaCl dissolved in water
hydrogen bonds: occurs between atoms w/ H bonded to a highly EN atom and found to occur in water, alcohols, amines, and carboxylic acids dipole-dipole: between polar molecules dispersion forces: found in nonpolar molecules and involves transient dipoles that arise from random fluctuations of electron density |
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what elements violate the octet rule?
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H, Be, B (incomplete octets) and elements from period 3 and down (more than 8)
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formal charge
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= # valence electrons - 1/2bonding + nonbonding
helps determine alternate lewis structures and the one with the smallest formal charge is preferred |
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lewis structures
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-determine # valence electrons in molecule
-put least EN atom in the center (usually C) -H and halogens usually on the outside -single bonds first -complete octets on outer elements -any extra electrons put unto center atom -if center atom had incomplete octet, use multiple bonds until it is complete |
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pressure
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force per unit area that gas molecule exert on the walls of the container
1 atm = 760 mm Hg = 760 torr |
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standard conditions
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-298K and 1 atm
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STP
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-273K and 1 atm
-gases often discussed in terms of STP |
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Ideal Gas Law Assumptions
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-gas particles take up no volume
-no intermolecular attractions between gas particles -random motion and they collide with eachother and walls of container elastically -KE proportional to T and is the same for all gases at a given T |
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mole fraction and partial pressure
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-mole fraction is equal to mol of gas X / total mol. of all gases present
-partial pressure is equal to (total P)(mole fraction) |
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rate law
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in the rxn aA + bB -> cC + dD
rate = [A]^x [B]^y where rxn order determined experimentally overall rxn order is x + y |
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factors affecting rxn rate
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-reactant concentration
-temperature -catalyst -solvent |
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equilibrium
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dynamic state in which forward and reverse reactions are equal
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equilibrium expression
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-products over reactants
-pure solids and liquids not included in equilibrium expression -if Keq more than 1 then there are more products around |
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Le Chatelier's Principle
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-if stress applied to sytem, sytem will respond in a way to relieve stress
-increase concentration of substance -> use it up and dec. its concentration -increase pressure -> decrease number of moles of substance -when temperature increased in endothermic rxn, rxn will shift to right; temp. dec. causes a shift to left to produce heat -when temperature is increased in an exothermic rxn, rxn will shift to left; if temp. dec. , rxn will shift to right to produce more heat to inc. temp. |
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solubility product constant
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-equilibrium of dissolved and solid solute
-describes concentrations at saturation level in which adding more solute causes solute to settle at the bottom -remember, pure solids and liquids don't appear in equilibrium expression -higher the solubility product constant, harder it is to reach saturation -generally inc. w/ inc. temp. |
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molar solubility
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-molar solubility is max moles of a substance that will dissolve in 1L of solution
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first law of thermodynamics
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-energy is conserved
-energy of a syste, can change by heat change or doing work -E = Q - W -E = Q + W |
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entropy
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-measure of disorder
-energy/temperature -increases with temperature |
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second law of thermodynamics
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-all spontaneous processes in an isolated system lead to an increase in entropy
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enthalpy
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-heat change of a rxn
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standard heat of formation
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-enthalpy change that occurs when a compound is formed froms its elements in their standard states
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Avogadro's number
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-6.022 x 10^23 particles
-1 gram = 6.022 x 10^23 amu |
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quantum
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-discrete bundles of energy emitted as electromagnetic radiation from matter
-energy value is E = hf |
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what is the centripetal force that acts on an electron as it revolves around the nucleus
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-the electrical force between the positively charged proton and negatively charged electron
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what do Planck's energy and the angular momentum of an electron have in common?
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-they're both quatitized
-Planck's energy depends on frequency of radiation -angular momentum depends on quantum # b/c everything else on angular momentum = nh /2 (3.14) is a constant |
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energy of an electron
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-E = -RH/n^2
-as quantum # increases, energy increases -energy changes as quantum # changes -zero energy when electron and proton completely seperated (no attractive force) -electron in any of its quantitized states has negative energy |
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the smaller the radius the lower/higher the energy state of the electron?
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lower
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what happens when electrons return to groud state after being excited?
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-they emit energy in the form of photons
-electromagnetic energy of these photons are E = hc/(wavelength) -different electrons in an atom will be excited to different energy levels and they will thus emit different photons characteristic of its transition -line spectrum produced -each element can have its electrons excited to different distinct energy levels, thus each one possesses a unique atomic emission spectrum -transition from one quantum # to another is equal to the energy of Planck's emitted photon (depends on frequency) -balmer and lyman series for hydrogen emission lines -each element also has a characteristic absorption spectrum b/c electrons absorb energy when they're excited -absorption corresponds to emission (equals energy difference between levels) |
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where are electrons located?
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-orbitals
-Bohr's assumption that electron follow a fixed orbital dastance is no longer valid |
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energy state of an electron
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-position and energy of an electron described by its quantum numbers
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