Midterm II Equations & Terms Flashcards
stoichiometric amounts
when compounds are mixed in the exact amounts needed for all molecules to be “used up” completely
limiting reagent (reactant)
compound that is completely used up
% yield
[(actual yield)/(theoretical yield)] x 100%
Water collective properties
1) many different forms of ice 2) high heat capacity 3) high boiling point 4) expands upon cooling 5) dissolves many different substances
What kind of molecule is water?
polar covalent (unequal electron sharing)
hydration
when a solid dissolves in water, the H (partial positive charge) orients itself toward a negative charge and vice versa with the partial negative charge
when a salt dissolves…
the cations and anions separate into individual ions
solute
substance dissolved
solvent
water (dissolved into)
strong electrolytes…
conduct electrical current strongly (ionize completely!)
weak electrolytes…
conduct electrical current weakly (ionize partially!)
non-electrolytes…
do not conduct electrical current (no ionization!)
what are strong electrolytes
substances that ionize completely when dissolved in water (ex. soluble salts, strong acids, strong bases)
generally soluble ions
Li+, Na+, K+, NH4^+, NO3^-, C2H3O2^-, Cl-, Br-, I-, SO4^2-
Cl-, Br-, I- solubility EXCEPTIONS
Ag+, Hg2^2+, Pb^2+ make compound INSOLUBLE
SO4^2- solubility EXCEPTIONS
Sr^2+, Ba^2+, Pb^2+, Ag+, Ca^2+ make compound INSOLUBLE
generally insoluble compounds
OH-, S^2-, CO3^2-, PO4^3-
OH- and S^2- insolubility EXCEPTIONS
Li+, Na+, K+, NH4^+, Ca^2+, Sr^2+, Ba^2+ make compound SOLUBLE
CO3^2- and PO4^3- insolubility EXCEPTIONS
Li+, Na+, K+, NH4^+ make compound SOLUBLE
strong acid list
HCl, HBr, HI, HNO3, H2SO4, HClO4
strong base list
NaOH, LiOH, KOH, Ca(OH)2, Ba(OH)2
weak acid
any acid that dissociates (ionizes) to only a slight extent in aqueous solution (ex. HC2H3O2, acetic acid)
non-electrolyte
substance that dissolves in water but doesn’t produce any ions
Molarity (M)
(moles of solute)/(liters of solution)
standard solution
solution whose concentration is accurately known
dilution equation
M1V1 = M2V2 (remember, DILUTION ONLY!)
molecular equation (ME)
shows reactants, products, and physical states
complete ionic equation (CIE)
shows everything as ions, INCLUDES “spectator” ions that do not participate in reaction
net ionic equation (NIE)
includes only the ions that participate in the reaction
when diluting, remember…
AAA (always add acid)
Bronsted-Lowry Definition
acid=proton (H+) donor, base=proton acceptor
the reaction is likely acid base if…
the products of the reaction include water and some ionic compound
volumetric analysis
technique for determining the amount of a certain substance by doing a titration
titration
carefully adding a solution of known concentration (titrant) to a solution of unknown concentration (analyte)
equivalence point (stoichiometric point)
when enough of the titrant has been added to react exactly with the analyte
indicator
a substance that’s added to the analyte that changes color at or very near the equivalence point (usually a weak acid/base)
endpoint
the point where the indicator actually changes color
successful titration
1) exact reaction b/w titrant and analyte must be known 2) equivalence point must be marked accurately 3) volume of titrant required to reach equivalence point must be known
acid-base titration
analyte and titrant are acid/base
gas-evolution reaction
when 2 aqueous solutions mix and produce a new gaseous substance that bubbles out of the solution
oxidation-reduction reactions (redox)
reactions in which one or more electrons are transferred
assigning oxidation state/# rules
1) oxidation state of pure element is zero 2) oxidation state of any monoatomic ion is equal to the charge on the ion 3) sum of oxidation states on a polyatomic ion equal the charge on the ion (0, -1, +3, etc) 4) fluorine in a molecule is always -1 5) hydrogen in a molecule is usually +1 6) oxygen is usually -2
oxidation
an increase in oxidation state (LOSS of electrons)
reduction
a decrease in oxidation state (GAIN of electrons)
Evangelista Torricelli
invented the mercury barometer (at sea level, barometer is at 760mmHg)
manometer
measures pressure of sample gas, heigh difference in sides indicates pressure of gas relative to atmospheric pressure
pressure conversions
1 atm = 760mmHg = 760 torr = 101,325 Pa = 29.92 inHg = 14.7 psi
Boyle’s law (Robert Boyle)
PV=k; pressure and volume are inversely proportional, P1V1=P2V2
Charles’s law (Jacques Charles)
V=bT; volume of gas is directly proportional to the temperature, T is in Kelvin, (V1/T1)=(V2/T2)
Avogadro’s law (Lorenzo Avogadro)
V=an; for a given gas at a constant temperature and pressure the volume is directly proportional to the number of moles of gas, (V1/n1)=(V2/n2)
Ideal gas law
PV=nRT, R = 0.08206 Latm/Kmol
molar mass of a gas
dRT/P, d=density