CHEM 1110: FINAL EXAM
172 Cards in this Set
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nm to m
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1 nm/ 1.0 × 10-9 m
1 m/1 000 000 000 nanometers
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μm to m
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1 m/1*10^6micrometers
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down the periodic table (ex. si-ge-sn) band gap _____
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decreases
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by adding ppm amounts of dopant additives, semiconductor electrical conductivity can be ____
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increased
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reducing the size of semiconductor particles (to nanometer dimensions) makes the band gap _______
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increase
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Hydrogen bond
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H & O, N, or F.
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which has the strongest dispersion forces?
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the one with the most electrons
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bond order
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the number of chemical bonds between a pair of atoms.
Bond order gives an indication of the stability of a bond.
higher bond order = more stable. 0=unstable
For example, in diatomic nitrogen N≡N the bond order is 3, in acetylene H−C≡C−H the bond order between the two carbon atoms is al…
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Hybrid Orbital vs. Number of bonding groups
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sp - 2
sp2 - 3
sp3 - 4
sp3d - 5
sp3d2 - 6
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C to K
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1 C/ 274.15 K
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intensive property
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do not depend on the amount of matter that is present
ex. boiling point, density, state of matter
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extensive property
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do depend on the amount of matter that is present
ex. volume, mass, size ENTHALPY
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Enthalpy...
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-dependent on state of reactants & products
-is a state function
-double amount of substance, double the enthalpy
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ΔE is always negative only when
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a system gives off heat and does work
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in condensation polymerization look for...
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a small molecule (usually H2O or HCl) that can be removed & joined together
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in addition polymerization look for...
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double bonds
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"increasing" ionic character a.k.a.
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the biggest difference in electronegativity
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oxidation number of O when it is bound to H
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+1
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formal charge
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6(valence e)-(4 bonding e)-(2 lone pair e)= FC of 0
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oxidation # of H when bound to H
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0
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redox reaction
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change in oxidation
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quantum # n
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electron shell. integers > 0.
distance of electron from nucleus
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quantum # m(l)
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magnetic q #
orbitals in subshell
l=1, m=1,0,-1
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quantum # "l"
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"azimuthal" angular momentum.
subshell type.
less than N.
0=S, 1=P, 2=D, 3=F, 4=D
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quantum # m(s)
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spin q #
electron spin
1/2 or -1/2
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vapor pressure
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-tendency for molecules to escape
-intensive (doesn't change on amount of stuff)
-stronger intermolecular forces = lower vapor pressures
-normal boiling point= temp which VP reaches 760 torr
-VP increases and liquid's temp increases
-equilibrium line btw gas & liquid = VP curve
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Q...
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...is the same as Keq when the reaction is at equilibrium
...& Keq depend on concentrations or partial pressures of reactants
...& Keq changes w temp
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C to K
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+273.15
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combustion reaction
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any hydrocarbon + O2
---> CO2 + H2O
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requirements for formation reaction (heat of formation)
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1. elemental
2. most stable form
3. form 1 mol of product
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paramagnetic
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-not fill orbitals, unpaired, lone e-
-attracted to magnetic fields
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Diamagnetic
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material that have PAIRED electrons, cannot easily be realigned and are REPELLED by magnets
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boiling point
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Ionic > Hydrogen bonding > dipole dipole > Van der Waals dispersion forces
increases as the number of carbons is increased.
Branching decreases boiling point.
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precision vs accuracy
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how close measurements are to each other vs how close they are to "true" value
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what proved the existence of electrons
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jj thompson's cathode ray experiment
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what proved the charge of electron & was used to determine e- mass?
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millikan's oil drops on plates
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radiation types
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alpha (+) bent by electric field
beta (-) bent by electric field, high speed e-'s, radioactive equivalent of cathode rays
gamma (neutral) high energy, similar to X-rays
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plum pudding model
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JJ Thompson early 1900's
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what experiment got us the nuclear model & idea of a nucleus
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Rutherford's alpha-particle scattering model
where the alpha particles passed thru gold foil & some scattered but some went thru
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mass #
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# of P AND N
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atomic #
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# of p
(equal to # of e-)
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12
C
6
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12- mass #
6 - atomic #
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cation
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postive ion
usually metals
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anion
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negative ion
usually nonmetals
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molecular compound
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pure substances formed from two or more nonmetals
(+1 type of atom?)
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alkanes
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where each carbon is bonded to 4 other atoms
(methane, ethane, propane, butane)
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alcohol
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replace H atom of an alkane w OH (methanol, ethanol, 1-propanol)
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combustion reaction
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rapid relations that produce a flame
hydrocarbons + O2 --> CO2 + H2O
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elemental composition
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% comp= 100x
(#atoms in element)(atomic weight of element)/formula weight of substance
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formula weight vs molecular weight
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-sum of the atomic weights of the atoms in its empirical formula vs.
-average mass as calculated by adding together the atomic weights of the atoms in the molecular formula.
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how to find empirical formula
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1. assume 100 g of substance and change percent to grams (75%=75g)
2. convert grams to moles for every element
3. get integral ratio by dividing all moles by smallest number of moles
4. multiply all moles by step 3 or any number to get a whole number
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find molecular formula from empirical formula
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(molecular weight) / (empirical formula weight)
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Strong Electrolytes
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-solutes that exist in solution completely or nearly completely as ions (NaCl and HCl)
-1 way reactions
-either a strong acid or base
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Weak Electrolytes
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-partially ionize in solution (weak acids and bases, such as H2S, NH3...)
-at any point are forming & disassociating
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water soluble ionic compounds are ___ electrolytes
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strong
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solubility rules pt. 1
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1. all group 1 metal salts, NH4+ salts, all NO3- salts, ClO4- salts, and C2H3O-2 salts (acetate) are soluble.
2. most Pb2+, Ag+, Hg22+ are INsoluble
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Solubility Rules pt. 2
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ammonia, alkali metal ions are ALWAYS soluble
nitrate, acetate ions are ALWAYS soluble
chloride, bromide, iodide are soluble EXCEPT with silver, mercury, and lead
carbonate, phosphate are usually NOT soluble
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ammonia, alkali metal ions are _____ soluble
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always
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nitrate, acetate ions are ______ soluble
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always
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chloride, bromide, iodide are soluble ____ with silver, mercury, and lead
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except
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carbonate, phosphate are usually ____ soluble
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Not
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metathesis reaction
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double displacement (exchange)
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acid
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any substance that yields hydrogen ions when put in aqueous solution (accepts OH)
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base
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produces hydroxide(OH-) ions in water
accepts (H+)
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Strong bases
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LiOH, NaOH, KOH, Ca(OH)2, Sr(HO)2, Ba(OH)2
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strong acids
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completely dissociate into anion and H+, strong acids are strong electrolytes
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Examples of Strong Acids (7)
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HI, HBr, HCl, HNO3, HClO4, HClO3, H2SO4
*the conjugate bases are weak bases
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ionic compound = _____ electrolyte
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strong
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neutralization reaction
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a reaction in which an acid and base react in aqueous solution to produce a salt and water.
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Redox Reaction
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electrons are
lost from one substance (oxidation) & added to another (reduction).
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assigning oxidation numbers
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atom in elemental form: 0
Monatomic ion: ON is it's charge
nonmetals: usually (-)
ex: O: -2, H: +1 w/ nonmetals, -1 w/ metals, F: -1, Halogens: -1.
3. sum of ON in neutral compound = 0
4. sum of ON in polyatomic= charge of the ion
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displacement reaction
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common with metals, producing salts and H2 gas
A+BX->AX+B
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activity series
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top: active metals, easily oxidized
bottom: noble metals, low reactivity
metals on list can be oxidized(gain e-) by metals below it
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molarity
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moles solute/
volume of solution (L)
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titration
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1. volume of standard solution to reach equivalent point ->
2.mol solute in standard solution ->
3. mol solute in unknown solution (use coefficients from balanced equation to find this)->
4. concentration of unknown solution (use volume of unknown solution)
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electrostatic potential energy
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Eel=kQ1Q2/d
Q's=electrical charges on 2 objects
d= distance separating
k= proportionality constant
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1 cal = ___ joules
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4.184 J
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1 Calorie = ____ cal = _ kcal
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1000 cal, 1 kcal
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closed systems allow transfer of ___ but not ____
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energy (work or heat), not matter
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isolated systems don't allow the transfer of ____
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anything
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work=___x___
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force x distance
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Law of Thermodynamics - First Law
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energy can neither be created nor destroyed
only converted from one form to another
The total energy of a system can be increased by doing work on it or by adding heat
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Change in energy
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delta E = work(w) + heat(q)
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+q =
-q =
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gain heat
loose heat
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+w=
-w=
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work done on system
work done by system
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energy is an _____ property
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extensive. depends on how much matter is in the system
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state function
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depends on present state only, not how it got there
ex. deltaE = w+q
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H = E + PV
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Enthalpy = Internal Energy + (Pressure x Volume)
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w=-P delta V
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formula for work in gaseous systems
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gas expands = ____ work
gas compresses= ____ work
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negative, positive
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Heat Capacity
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Amount of heat required to raise the temperature of an object by 1dC
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specific heat
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quantity of heat transferred/
(grams of substance)(temp change)
q/m(T)
q=m(T)Cs
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calorimeter heat transfer
reaction to water = ___
water to reaction=____
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exothermic
endothermic
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high molar mass & pressure = ___ density
high temp= __ density
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high
low
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Kinetic Molecular Theory of Gases
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as temp increases, average speed at which molecules move increases
*molecules do not attract each other
* volume of the gas molecules is negligible compared to the total volume of the gas
*continuous, random motion
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effusion
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escape of gas molecules through a tiny hole
*lighter gases have a higher rate
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diffusion
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spread of one substance throughout a space
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at higher temps & lower pressures, real gases behave more like ___
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ideal gases
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THe Haber Process
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Production of ammonia
N2(g) + 3H2(g) → 2NH3(g)
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Law of Mass Action
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Expreses the relative concentrations of reactants and products at equilibrium Kc for molarity, Kp for gas
Kc = [D]d[E]e
_________
[A]a[B]b
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K = 1 or Q = K
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at equilibrium
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If K is small (K<1),
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[reactants] is greater than [products] at equilibrium
(reactant-favored)
equilibrium lies to the left
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If Kc is big (K>1)
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[products] is greater than [reactants] at equilibrium
(product-favored)
equilibrium lies to the right
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Homogeneous Equilibria
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substances in reaction are in the same phase
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heterogenous equilibria
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substances in reaction are in the same phase. IGNORE SOLIDS AND LIQUIDS (not aq)
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Q < K
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concentration of products too little. shift L to R to form more products
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Q=K
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The reaction is at equilibrium, no shift
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Q > K
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too high concentration of products. shirt R to L to form more reactants
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heat is a reactant. High K
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endothermic
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heat is a product. Low K
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exothermic
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endothermic
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heat flows into the system
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Exothermic
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release of heat
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wavelength⟼
frequency⟻
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gamma, x, UV, visible, infrared, radio
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photoelectric effect
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minimum frequency of light required for different metals to emit e-
EINSTEIN
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if photon energy > work function, then e- are ____
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emitted
access energy of photon is turned into kinetic energy of emitted electron
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Bohr's postulates
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1. Only electron “orbits” of certain energies are allowed (the energy of an e- is quantized)
2. An electron in a “permitted orbit” has a specific energy (an allowed energy “state”)
3. An electron in an allowed state is stable and will not radiate energy
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Limitations of the Bohr Model
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1. Only works for single-electron atoms
2. Cannot account for fine spectral line intensity
3. Cannot explain binding of atoms into molecules
4. cannot explain wave-like properties
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radial probability function
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the probability that we will find the electron at a specific distance from the nucleus
Nodes: probability = 0e
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degenerate orbitals
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orbitals that have equal energies
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Pauli Exclusion Principle
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No 2 electrons in an atom can have the same 4 quantum numbers.
Must have opposite spins
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hund's rule
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each orbital in a subshell is half-filled(w 1 electron) and prior to filling the orbitals(w 2 electrons)
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effective nuclear charge
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increases left to right
increases down
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bonding atomic radius
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1/2d (bond distance)
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periodic trends in radius size
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radius increases from R to L
radius increases from top to bottom
CATIONS are smaller than parent ions, ANIONS are larger
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Isoelectric Series
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-group of atoms and ions that contain the same number of electrons
-ionic radius decreases with increasing nuclear charge
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Ionization Energy
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-The energy required to remove an electron from the atom in the gaseous state.
-increases to the R & Up
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electron affinity
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energy associated with the gain of an electron in the gas phase
the more negative EA, the stronger the e- is attracted to the nucleus
variation in EA generally follows atomic radius (R to L, bottom to top)
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metals have __ ionization energy
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low. they make cations easily
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most metal oxides are ___ and dissolve in water to make ____
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basic
metal hydroxides
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nonmetals have large, ___ EAs
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negative
tend to gain e- when reacting w metals
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compounds of nonmetals are ____
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molecular
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nonmetal oxides are usually ____
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acidic.
+H20 = acid
+base= salt & water
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Lattice Energy
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the energy required to separate one mole of the ions of an ionic compound
decreases DOWN
(+) values, higher = strong attractions
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lattice energy increases with ____ charge and ____ radii
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increasing
decreasing
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polar covalent bond
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one of the atoms has a greater attraction for the bonding e- than the other
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Electronegativity
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The ability of an atom to attract electrons toward itself in a chemical bond.
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high electronegativity = ___ ionization energy, ____ EA
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high, (-)
increases UP & RIGHT
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difference in electronegativity makes a ___
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dipole moment (polar molecule)
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formal charge
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valence e-
- (1/2) bonding e-
- nonbonding e-
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exceptions to octet rule
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*odd # of e-
*Boron needs 6
*central period 3 and below are hypervalent (+8 e-)
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bond enthalpy
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the delta H (energy) for breaking of a particular bond in 1 mol of a gaseous substance
ALWAYS POSITIVE
greater enthalpy = stronger bond
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when bonds form, energy is __
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released (exothermic)
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linear - linear
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2 electron domain
sp hybridization
2 bonding pairs 0 lone pairs
180
ex. CO2
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trigonal planar - trigonal planar
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3 electron domain
sp2 hybridization
3 bonding pairs 0 lone pairs
120
ex. BF3
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trigonal planar - bent
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3 electron domain
sp2 hybridization
2 bonding pairs 1 lone pairs
119
ex. SO2
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tetrahedral - tetrahedral
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4 electron domain
sp3 hybridization
4 bonding pairs 0 lone pairs
109.5
ex. CH4
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tetrahedral - trigonal pyramidal
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4 electron domain
sp3 hybridization
3 bonding pairs 1 lone pairs
107
ex. NH3
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tetrahedral - bent
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4 electron domain
sp3 hybridization
2 bonding pairs 2 lone pairs
104.5
ex. H2O
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trigonal bipyramidal - trig. bipyramidal
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5 electron domain
sp3d hybridization
5 bonding pairs 0 lone pairs
90, 120, 180
ex. PCl5
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trig. bipyra. - seesaw
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5 electron domain
sp3d hybridization
4 bonding pairs 1 lone pairs
86.5, 102, 187
ex. SF4
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trig. bipyra. - T shape
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5 electron domain
sp3d hybridization
3 bonding pairs 2 lone pairs
87.5, 185
ex. ClF3
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trig. bipyra. - linear
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5 electron domain
sp3d hybridization
2 bonding pairs 3 lone pairs
180
ex. XeF2
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octahedral - octahedral
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6 electron domain
sp3d2 hybridization
6 bonding pairs 0 lone pairs
90, 180
ex. SF6
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octahedral - square pyramidal
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6 electron domain
sp3d2 hybridization
5 bonding pairs 1 lone pairs
84.8, 180
ex. BrF5
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octahedral - square planar
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6 electron domain
sp3d2 hybridization
4 bonding pairs 2 lone pairs
90
ex. XeF4
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hybridization vs electron domain
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2 - sp
3 - sp2
4 - sp3
5 - sp3d
6 - sp3d2
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electron domain - hybridization - molecular shape
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2 - sp - linear
3 - sp2 - trigonal planar
4 - sp3 - tetrahedral
5 - sp3d - trigonal bipyrimidal
6 - sp3d2 - octahedral
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LINEAR
e- pair geometry vs molecular geometry
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linear
2 - sp
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TRIG. PLANAR
e- pair geometry vs molecular geometry
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trig planar - 3,0
bent- 2,1
3 - sp2
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TETRAHEDRAL
e- pair geometry vs molecular geometry
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4,0 - tetrahedral
3,1 - trig. planar
2,2 bent
4 - sp3
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TRIG. BIPYRAMIDAL
e- pair geometry vs molecular geometry
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5,0 - trig. bipyramidal
4,1 - seesaw
3,2 - T-shaped
2,3 - linear
5 - sp3d
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OCTAHEDRAL
e- pair geometry vs molecular geometry
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6,0 - octahedral
5,1 - square pyramidal
4,2 - square planar
6 - sp3d2
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electronegativity arrows shape thing
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shape = non polar
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sigma bond is ___ than a pi bond
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stronger
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bond order
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1/2(bonding electrons - non bonding electrons)
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Crystal Vs. amorphous Structure
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Crystal
periodically repeated structure, long range order in 3D.
In general, metals.
SLOW TRANSITIONS
Narrow range of melting temps
amorphous
no periodicity, no long range order
rapid liquid to solid
broader melting temps
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simple cubic
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1/8 atom at each corner, 1 atom total
least dense (inefficient)
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body centered cubic
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an extra atom that sits in the center, 2 atoms per cell
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face-centered cubic (FCC)
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found in some of the common elemental metals.
atoms are located at all corner and face-centered positions.
4 atoms/unit cell (inside ones are 1/2)
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Hexagonal Close-Packing
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6 atoms/unit cell
coordination number=12
same APF as FCC = 0.74
ABAB stacking sequence- equilateral triangles
1.633=c/a
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Addition polymerization
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Are formed when monomer units join each other in a process that involves rearranging electrons in double or triple bonds in a monomer.
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Condensation Polymerization
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two molecules are joined to form a larger molecule by the elimination of a small molecule, usually H2O
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CHEM 1110: General Chemistry Test 1