Exam 2 Flashcards
What are two reasons why the actual yield from a chemical reaction is usually less than the theoretical yield?
1) The observed, or actual, yield for a reaction is usually less than the theoretical yield because reactions do not always go to completion
2) the reaction may be slow or may have, for a portion of the reaction, created different products than expected
What kind of anhydride is dichlorine trioxide? What type of solution will be formed? What color litmus paper should be used to test the relative pH of the solution formed?
Cl2O3 is a nonmetal oxide and an acid anhydride.
Acidic Cl2O3+H2O —> [H2Cl2O4] —> 2HClO2 which is a weak acid
Blue paper should be used to test for acidity
What kind of anhydride is potassium oxide?
K2O metal oxide and a base anhydride
Basic: K2O + H2O —> 2KOH which is a strong base
Use red litmus paper to test for basicity
What are the differences between strong electrolytes, weak electrolytes, and non-electrolytes in terms of i) electrical conductivity in water and ii) how they dissolve in water
- Strong electrolytes conduct a strong electrical current and dissociate 100% into ions in H2O
- Weak electrolytes conduct a weak electrical current and dissociate less than 100% into ions in H2O (mostly neutral molecules)
- Non-electrolytes conduct no electrical current and dissolve as neutral molecules in H2O
Identify as a strong, weak, or non electrolyte when dissolved in water. Indicate how it dissolves in water.
CaCl2*
Strong electrolyte
Ions
Ca+2 + 2Cl-
NH3*
Weak electrolyte
Weak base
Mainly NH3
HCLO4*
Strong electrolyte
Strong acid
H+ + CLO4-
Fe(NO3)3*
Strong electrolyte
Ions
Fe+3 + 3NO3-
Ba(OH)2*
Strong electrolyte
Strong base
Ba+2 + 2OH-
H2SO3
Weak electrolyte
Weak acid
H2SO3
O2*
Non-electrolyte
Molecular compound
O2
(CH3)2NH*
Weak electrolyte
Weak base
(CH3)2NH
AgNO3*
Strong electrolyte
Ionic
Ag+ + NO3-
AgCL*
Non-electrolyte
Insoluble I.C
AgCL
NiSO4*
Strong electrolyte
Ionic
Ni2+ + SO4-2
BaSO4*
Non-electrolyte
Insoluble I.C
BaSO4
C12H22O11*
Non-electrolyte
Molecular compound
Neutral
HNO2*
Weak electrolyte
Weak acid
HNO2
HCLO2*
Weak electrolyte
Weak acid
Mainly HCLO2
C2H5OH
Non-electrolyte
Molecular compound
C2H5OH
HNO3*
Strong electrolyte
Strong acid
H+ + NO3-
H2S*
Weak electrolyte
Weak acid
Mainly H2S
What are the Bronsted-Lowry definitions for acids and bases?
Acid: proton donor
Base: proton acceptor
What are the Arrhenius definitions for acids and bases?
Acid: produces H+ when dissolved in H2O
Base: produces OH- when dissolved in H2O
What are the differences between strong and weak acids?
Strong acids dissociates/ionizes 100% to produce H+/H3O+
Weak acid is less than 100% dissociation
What are the differences between strong and weak bases?
Strong bases dissociate 100% and weak bases less than 100% to produce OH-
List the strong acids
HI, HCL, HBr, HNO3, HCLO3, HCLO4, H2SO4
List the strong bases
LiOH, NaOH, KOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
Short of weak acids
H3PO4, H2S, HC2H3O2, HNO2, H2SO3, HCLO3-
Short list of weak bases
NH3, NH2OH, CH3NH2, (CH3)2NH
Discuss the electrolyte activity of strong and weak acids and bases.
Strong acids/bases are strong electrolytes and weak acids/bases are weak electrolytes
CH3CH2CH2OH
Is not a strong base
Is not a hydroxide
Is an alcohol
It differs from NaOH when it dissolves in water because propanol is a molecular compound, so even though it dissolves, it does not dissociate into ions like NaOH does
Any substance that has the (aq) designation splits into ions when dissolved in solution…..true or false
False because the (aq) designation only indicates that a substance dissolves in water but NOT how it dissolves. It should read “Any substance that is a strong electrolyte splits into ions when dissolved in aqueous solution”
Define equivalence point
Point where stoichietric amounts of both reagents are present
Define indicator
Substance with one color in more acidic solutions and different color in more basic
Define end point
Point in titration where indicator changes color
Define the term solute
Any component in a solution other than the solvent
Substance dissolved in solvent
Define the term solvent
A component of a solution that is present in the greatest amount
Substance dissolving the solute
Define the term solution
Resulting mix of solute and solvent, solute in uniformly distributed
Define solubility
Measure of maximum amount of solute that will dissolve in a given amount of solvent (measured in g/100mL)
Define unsaturated solution
a chemical solution in which the solute concentration is lower than its equilibrium solubility
Define saturated solution
a chemical solution containing the maximum concentration of a solute dissolved in the solvent
Define supersaturated solution
a state of a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances
Solubility Rule 1
Ionic compounds that contain Group 1(IA) metal cations (Na+, K+, Li+, etc.) or ammonium (NH +) are soluble.
4
Solubility Rule 2
Ionic compounds that contain NO -, ClO -, ClO -, C H O -, or HCO - are soluble.
Solubility Rule 3
Ionic compounds that contain Cl-, Br-, or I- (halogens) are soluble EXCEPT when combined with Cu+, Ag+, Hg 2+, or Pb2+. Most F- compounds are soluble EXCEPT when combined with Pb2+ and Group 2(Ca+2, Ba+2, etc).
Solubility Rule 4
Ionic compounds that contain SO 2- are soluble EXCEPT when combined with Ag+, Hg 2+,
2+ 2+ 2+ 2+ 4 2 Pb , Ca , Sr , or Ba . Note: Ag2SO4 is sparingly soluble.
Solubility Rule 5
Most ionic compounds that contain OH-, O2-, CO 2-, PO 3-, CrO 2-, or S2- are insoluble 344+
EXCEPT when combined with Group 1(IA) metal cations or NH4 .
– Extra exception(s): CrS, SrS, and BaS are considered soluble. Ca(OH)2, Ba(OH)2, and Sr(OH)2 are considered soluble. Group 1 and heavier Group 2 oxides react with water to form corresponding hydroxide which is soluble.
Solubility Rule 6
Combining anions and cations not listed above results in formation of an insoluble compound
