Unit 2

Question 1

Bronsted-Lowry acid/base definition

Answer 1

-acid is an H+ donor
-base is an H+ acceptor

Question 2

Arrhenius acid/base definition

Answer 2

-acid produces H3O+ in water
-base produces OH- in water

Question 3

Strong acid

Answer 3

-(HA) reacts completely in water to produce H3O+
-better proton donor (H+) than the conjugate acid of the solvent (H3O+ for water)

Question 4

Strong acids

Answer 4

-HI
-HBr
-HCl
-HClO4
-HNO3
-H2SO4
-HClO3

Question 5

Strong acids (full names)

Answer 5

-HI (hydroiodic acid)
-HBr (hydrobromic acid)
-HCl (hydrochloric acid)
-HClO4 (perchloric acid)
-HNO3 (nitric acid)
-H2SO4 (sulfuric acid)
-HClO3 (chloric acid)

Question 6

Weak acid

Answer 6

-(HA) only partially deprotonates in water
-weaker proton donator than conjugate acid of solvent (H3O+)

Question 7

Weak acid ionization constant (Ka)

Answer 7

-the equilibrium constant that measures the extent to which a weak acid ionizes in water
-Ka = [H+][A−] / [HA]

Question 8

Strong base

Answer 8

-(A-) reacts completely with water to produce OH-
-better proton acceptor (H+) than the conjugate base of the solvent (OH- for water)

Question 9

Strong bases

Answer 9

-CH3-
-H-
-NH2-
-O(2-)
-OH-
-S(2-)

Question 10

Strong bases (full names)

Answer 10

-CH3(-) (methide)
-H- (hydride)
-NH2(-) (amide)
-O(2-) (oxide)
-OH- (hydroxide)
-S(2-) (sulfide)

Question 11

Weak base

Answer 11

-(A-) only partially protonates in water
-weaker proton acceptor than conjugate base of solvent (OH-)

Question 12

Weak base ionization constant (Kb)

Answer 12

-the equilibrium constant that measures the extent to which a weak base ionizes in water
-Kb = [HA][OH-] / [A-]

Question 13

ionization

Answer 13

-the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons
-gain/loss of H+ (proton)

Question 14

Conjugate See-Saw

Answer 14

-the strongest weak acid has the weakest conjugate base
-the weakest acid has the strongest conjugate base

Question 15

Solvent leveling

Answer 15

-acidities of strong bases/acids are identical in water
-The solvent’s acidity limits strong bases, and its basicity limits strong acid
-The solvent can only provide a certain amount of protons for acids or accept a certain amount of protons for bases

Question 16

Conjugate facts

Answer 16

-conjugates of weak acids are weak bases (and vice versa)
-conjugates of strong acids are not basic in water
-conjugate of strong bases are not acidic in water

Question 17

Strong acids in NH4

Answer 17

HA + NH3 -> NH4+ + A-

Question 18

Strong bases in NH4

Answer 18

A- + NH3 -> NH2- + HA

Question 19

Finding pH

Answer 19

Moles= 10^-pH
pH= -log[H+]

Question 20

Kw

Answer 20

-the equilibrium constant for the self-ionization reaction of water
-water is amphiprotic (can serve as acid/base)
-Kw= (Ka)(Kb)

Question 21

pH scale

Answer 21

-in pure water: pH=7 (1 x 10^-7)
-in acidic solution: pH < 7
-in basic solution: pH > 7

Question 22

pH, pOH, and pKw

Answer 22

-Kw = (H3O+)(OH-)
-pKw = pH + pOH
-pKw= pKa + pKb (same as Kw= (Ka)(Kb), just taken to -log)

Question 23

pKw

Answer 23

-at room temp (25C), pKw= 14

Question 24

% Dissociation in water

Answer 24

-for base dissociation: (A-)/(HA) x 100
-for acid protonation: (HA)/(A-) x 100

Question 25

Buffer

Answer 25

-a solution that contains both a weak acid (HA) and its conjugate weak base (A-) -buffers are resistant to pH changes, maintain an approximate pH value even in strong acid/base

Question 26

Henderson-Hasselbach Equation (acids)

Answer 26

-pH = pKa - log(10)[(HA)/(A-)] -can be used to estimate the pH of a buffer solution -[HA] and [A⁻] refer to the equilibrium concentrations of the conjugate acid–base pair used to create the buffer solution

Question 27

pKa

Answer 27

-acid dissociation constant -how readily a molecule donates a proton (hydrogen ion) -indicates the strength of an acid -a lower pKa value signifies a stronger acid (more easily releases a proton in solution)

Question 28

pKb

Answer 28

-base dissociation constant -how well a base accepts protons from water -how strong the base is compared to others -higher pKb indicates stronger base

Question 29

Henderson-Hasselbach Equation (bases)

Answer 29

-pOH = pKb - log(10)[(A-)/(HA)] -can be used to estimate the pOH of a buffer solution

Question 30

Diluting buffer

Answer 30

-apply dilution factor -find Q and compare to K to see which way reaction occurs -complete ICE table and find x -pH usually doesn't change although concentrations do

Question 31

NH3 (ammonia)

Answer 31

-provides a different chemical environment for studying reactions -more compounds act as strong acids in ammonia than water and less strong bases -strong acids= stronger than NH4+ -strong bases= stronger than NH2-

Question 32

Ka

Answer 32

-acid ionization constant -[H3O+][A-]/[HA] -larger Ka = stronger acid (less HA, more H3O+) -larger Ka = smaller pKa (more acidic)

Question 33

Kb

Answer 33

-base ionization constant -[OH-][HA]/[A-] -larger Kb= stronger base (less A-, more OH-) -larger Kb = smaller pKb (more basic)