Ch4 aqueous reactions Flashcards
aqueous solution
solutions which water is the dissolving medium,
The substance of greatest quantity is the solvent and the other substances are the solutes and are dissolved in the solvents
electrolyte
substance (such as NaCl) whose aqueous solutions contain ions and will conduct electricity. If you put an electric current in the solution, the ions will conduct them and light the light bulb
nonelectrolyte
substance (such as C12H22O11–sucrose) that does not form ions in solution and does not conduct electricity
strong electrolytes
Strong electrolytes are solutes that exist in solution completely or nearly completely as ions. Include all soluble ionic compounds (NaCl) and few molecular compounds (HCl). Can be written as HCl(aq)H+(aq)+Cl-(aq), meaning ions have no tendency to recombine in water. Soluble ionic compounds are strong electrolytes
weak electrolytes
Weak electrolytes are solutes that exist in solution mostly in form of molecule with only a small fraction in the form of ions (acetic acid-HC2H3O2). Can be written as HC2H3O2(aq)H+(aq)+C2H3O2-(aq). means reaction is significant in both directions, molecules are ionizng at same time ions are recombining to form molecules
chemical equilibrium
Balance between opposing processes produces state of chemical equilibrium that varies between weak electrolytes
precipitation reaction
reactions that result in formation of an insoluble product (precipitate). Occurs when certain pairs of oppositely charged ions attract each other so strongly that they form an insoluble ionic solid
solubility
The solubility of a substance at a given temperature is the amount of that substance that can be dissolved in a given quantity of solvent at that temperature
Any substance with a solubility less than 0.01 mol/L is insoluble and will form precipitate
soluble ionic compounds4
All group 1 + ammonium ion ionic compounds(NH4+)
all compounds with NO3- or C2H3O2-
Cl-, br, and I: except with Ag+, Hg22+, Pb2+
SO42-except withSr2+, Ba2+ Hg22+, Pb2+
insoluble ionic compounds2
S or OH:except with alkali metal cations (group 1),NH4+, Ca2+, Sr2+, Ba2+
CO3 or PO4: except with alkali metal cations (group 1), NH4+
metathesis reaction
positive ions and negative ions appear to exchange partners. AX+BY→ AY+BX. Seen in precipitation reaction and acid-base reactions.
spectator ion
ons that appear in identical forms among both reactants and products of a complete ionic equation and play no direct role in the reaction (both sides. K and NO3 in above equation) If every ion in a complete ionic equation is a spectator, then no reaction occurs.
acids
Acids are substances that ionize in aqueous solutions to form H ions, increasing the concentration of H ions
H+(aq)is simply a proton because H is a proton+electron. Acids are often called proton donors.
monoprotic acid
(HCl and HNO3) yield one H+ per molecule of acid.
diprotic acid
(H2SO4) yields 2 H+ per molecule of acid. Its ionization occurs in two steps: 1)H2SO4–>H+ +HSO4-, 2) HSO4-H+ +SO4-. H2SO4 is a strong electrolyte, but only first ionization is complete so aqueous solution of sulfuric acid contains mixture of H, SO4- and SO42-
bases
Bases are substances that accept (react with) H+ ions and produce hydroxide OH- ions when they dissolve in water. (most common bases: NaOH, KOH, Ca(OH)2
strong acids7
HCl, HBr, HI, HClO3, HClO4, HNO3, H2SO4
halogens and some -ates
strong bases8
LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
group 1 bases and group 2
strong/weak acids/bases
Acids and bases that are strong electrolytes are strong acids and strong bases. Strong acids are more reactive that weak acids, based on the concentration of H+.
Those that are weak electrolytes (partly ionized) are weak acids and weak bases.
strong/weak/non electrolyte?
To determine if an acid or base is a strong/weak/non electrolyte:
1) is it ionic? yes=strong.
2) no=molecular. Is it acid (has H in front) or base?
3) Refer to list of strong acids/bases. If not on list=weak. NH3 is only weak base.
4) if not acid or bases=non
neutralization reaction
When an acid and base are mixed, a neutralization reaction occurs which produces water and a salt (salt=any ionic compound whose cation comes from base and anion comes from acid.HCl(aq)+NaOH(Aq)H2O(l)+NaCl(Aq)
gas formation
Other compounds can react with H+ to for gas. Compounds with S (Na2S) can react with acids to form H2S gas. carbonates/bicarbonates can react with acids to form CO2 gasses.
redox reaction
oxidation-reduction /redox reactions are when electrons are transferred between reactants.
oxidation number
Each atom in a neutral molecule or charged species is assigned an oxidation number/oxidation state which is the actual charge for a monatomic ion, or the hypothetical charge assigned to the atom, assuming the electrons are completely held by one atom or the other
Oxidation occurs when the oxidation # increases, reduction occurs when the oxidation # decreases
elemental form ox number
0
p4 ox #=0
monatomic ion ox #
charge of ion
k ox#=+1
all non metals except o,h,halogens ox #
negative
O ox#
usually -2, except peroxide which is -1
H ox#
+1 with nonmetals and -1 with metals
halogens ox#
F= -1 always, other halogens are -1 except when combined with O(oxyanions) then it is positive
sum of ox#2
Sum of ox# of all atoms in a neutral compound is zero. Sum of ox# in a polyatomic ion equal charge of ion. H3O+: ox# of H is +1, ox# of O is -2. 3(+1)+(-2) =+1→ net ionic charge of H3O ion
displacement reaction
Displacement reaction are redox reactions between a metal with either an acid or a metal salt: A+BX→ AX+B. the electrons from B go to A while X does not change
activity series
The activity series is the list of metals arranged in order of decreasing ease of oxidation
Active metals at the top of the table (alkali metals and alkaline earth metals) are most easily oxidized and can most readily form compounds while the metals at the bottom are called noble metals (metals from 8B and 1B) and are more stable and form compounds less readily. Any metal on the list can be oxidized by the ions of elements below it
concentration
Concentration is the amount of solute dissolved in a given quantity of solvent or quantity of solution. The greater solute=more concentrated
The relative concentrations of ions in a solution depend on the chem formulas. 1.0M of Na2SO4 contains 2.0M Na+ and 1.0M SO42-
molarity
Molarity (symbol M) expresses the concentration of a solution as the number of moles of solute in a liter of solution. Molarity= moles solute/volume of solution in liters
dilution
Solutions of lower concentrations can be obtained by adding water, a process called dilution. Moles solute before dilution=moles solute after dilution. MconcVconc=MdilVdilMconc>Mdil and Vconc
titration
A titration involves combining a sample of the solution with a reagent solution of known concentration, called a standard solution
