10 Acids, Bases, and Salts

required indicator for the titration of: a. a weak acid by a strong base b. a weak base by a strong acid

a. indicator that changes color above pH 7.0 b. indicator that changes color below pH 7.0

Give the nature of aqueous solution: a. strong acid-strong base b. strong acid-weak base c. weak acid-strong base d. weak acid-weak base

a. neutral b. acidic c. basic d. depends on the salt

Which of the following is an electrolyte? a. salt b. sucrose c. glucose d. isopropyl alcohol

a. salt

Give what is asked: Weak acids a. Amount of protons transferred in an aqueous solution. b. Equilibrium c. Predominant Species

a. usually <5% b. far to the left c. HA

equilibrium constant for the reaction of a weak acid with water; defines how much of the reactants would be dissociating to form the products

acid ionization constant

a compound that exhibits different colors in a solution depending on the pH of its solution

acid-base indicator

chemical reactions between an acid and a hydroxide base in which salt and water are the products

acid-base neutralization

a neutralization reaction in which a measured volume of an acid or a base of known concentration is completely reacted with a measured volume of a base or an acid of unknown concentration

acid-base titration

hydrogen atoms in an acid that can be transferred to a base in an acid-base reaction

acidic hydrogen atoms

reaction of the positive ion from a salt with water to produce the ion's conjugate base and hydronium ion

acidic hydrolysis

Solution where H3O+ > OH-

acidic solution

aqueous solution whose pH is less than 7.0

acidic solution

substance that can either lose or accept a proton and thus function as either a Bronsted-Lowry acid or a Bronsted-Lowry base

amphiprotic substance

mathematical definition of pH

pH = -log[H3O+]

a scale of small numbers used to specify molar hydronium ion concentration in an aqueous solution

pH scale

the negative logarithm of the acid ionization constant (Ka) for a weak acid

pKa

acid that can supply two (2) or more protons during acid-base reactions; several proton transfer steps occur in each type of these acids

polyprotic acid

chemical reaction of salt with water to produce hydronium ion or hydroxide ion or both

salt hydrolysis reaction

ionic compounds containing a metal or a polyatomic ion as the positive ion and a nonmetal or a polyatomic ion as the negative ion

salts

process wherein an extremely small percentage of water molecules in pure water interact with one another to form ions

self-ionization

acid that is indicated by H3A

triprotic

the typical and more common composition of a buffer

weak acid and its conjugate base

TRUE OR FALSE: Ionization and strength of acids depend on molecular structure, such as molecular polarity and strength of individual bonds.

TRUE

TRUE OR FALSE: Solutions can be classified as acidic or basic based on their H3O+ and OH- concentrations.

TRUE

TRUE OR FALSE: Water can only significantly attach to hydrogen with polar bonds.

TRUE

TRUE OR FALSE: addition of a base leads to equilibrium shifting to the right, the addition of an acid leads to equilibrium shifting to the left

TRUE

TRUE OR FALSE: pKa for an acid is calculated from Ka in exactly the same way that pH is calculated from hydronium ion concentration

TRUE

WHICH IS NOT TRUE: Ion Product Constant a. At equilibrium and 100 C, the H2O+ and OH- concentrations are 1.00 x 10-7 M each b. Ion product constant for water (Kw) is obtained by multiplying together the H3O+ and OH- concentrations c. The ion product constant is valid for both pure and solute-containing water d. Despite the contents of the solutions, the product of [H3O+] and [OH-] must always be 1.00 x 10-14

a. - At equilibrium and 24C, the H2O+ and OH- concentrations are 1.00 x 10-7 M each

WHICH IS NOT TRUE: Acids and Bases a. Most acids are strong. b. Most bases are weak. c. Strong bases are limited to the hydroxides of Groups IA and IIA. d. Stomach acid is a dilute solution of strong acid.

a. - Most acids are WEAK.

WHICH IS NOT TRUE: Salt Hydrolysis a. all salts hydrolyze b. hydrolyzing salts produce either acidic or basic solutions in water c. the acidity or basicity of the solution can be guided by the parentage of the salt d. parentage can be determined by writing the neutralization equation that produced the salt

a. - NOT all salts hydrolyze

Give what is asked: Strong acids a. Amount of protons transferred in an aqueous solution. b. Equilibrium c. Predominant Species

a. 100% or ~100% b. far to the right c. H3O and A-

contains one more H atom and more + charge than the base that formed it

conjugate acid

contains one less H atom and more - charge than the acid that formed it

conjugate base

frequently used in specifying electrolyte concentrations due to relatively low concentrations of ions present in bodily fluids

milliequivalents

an acid that can supply only 1 H+ per molecule during acid-base reaction

monoprotic

Solution where H3O+ = OH-

neutral solution

aqueous solution whose pH is 7.0

neutral solution

substance whose aqueous solution does not conduct electricity; substances that do not produce ions in solution

non-electrolyte

two possible forms of stressors applied in buffers

- addition of base or hydroxide ion - addition of acid or hydronium ion

Enumerate: Strong Acids

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

Enumerate: Strong Bases

- lithium hydroxide (LiOH) - sodium hydroxide (NaOH) - potassium hydroxide (KOH) - rubidium hydroxide (RbOH) - cesium hydroxide (CsOH) - calcium hydroxide (Ca(OH)2) - strontium hydroxide (Sr(OH)2) - barium hydroxide (Ba(OH)2)

QUANTITATIVE COMPARISON: Acidity 1. hydrogen attached to carbon atom 2. hydrogen bonded to oxygen atom

1 < 2

QUANTITATIVE COMPARISON: Conductivity 1. non-electrolyte 2. weak electrolyte 3. strong electrolyte

1 < 2 < 3

a hydrogen-containing compound that produces H+ ions in an aqueous solution

Arrhenius Acid

hydroxide-containing compound that produces OH- ions in aqueous solution

Arrhenius Base

substance that can donate a proton (H+) to some other susbtance

Bronsted-Lowry Acid

substance that can accept a proton (H+) from some other substance

Bronsted-Lowry Base

TRUE OR FALSE: A change in 1 unit pH is equal to a sevenfold change in H3O+.

FALSE - A change in 1 unit pH is equal to a TENFOLD change in H3O+.

TRUE OR FALSE: Not all common soluble salts are completely dissociated into ions in a solution.

FALSE - ALL common soluble salts are completely dissociated into ions in a solution.

TRUE OR FALSE: In an electrolytic solution, a charge balance must exist among the ions present, thus, equal amounts of positive ions must be present.

FALSE - In an electrolytic solution, a charge balance must exist among the ions present, thus, equal amounts of positive CHARGES must be present, not necessarily ions.

TRUE OR FALSE: All acids and bases included in the Arrhenius theory are also acids and bases according to Bronsted-Lowry theory, and vice versa.

FALSE - the first statement is true, yet its vice versa is false.

acidic species in the Arrhenius Acid-Base theory

H+

basic species in the Arrhenius Acid-Base theory

OH-

TRUE OR FALSE: Base produces hydroxide ions once it reacts with water.

TRUE

WHICH IS NOT TRUE: pH and concentration a. pH of a solution gives information about the concentration of hydronium ions in the solution b. all molecules influence the pH value c. concentration of an acid or a base gives information about the total number of acid or base molecules present d. concentration of an acid or base involves both dissociated and undissociated molecules

b. - ONLY IONIZED molecules influence the pH value

WHICH IS NOT TRUE: Arrhenius Base a. have a bitter taste b. are inherently slippery c. turn red litmus paper to blue d. are ionic compounds in pure state

b. - are NOT inherently slippery; simply react with oils in the skin to form new slippery compounds

WHICH IS NOT TRUE: Arrhenius Acids a. are molecular compounds in pure state b. undergo dissociation c. turn blue litmus paper to red d. have a sour taste and are corrosive

b. - undergo IONIZATION

equilibrium constant for the reaction of a weak base with water; follows the same principle as acid strength

base ionization constant

reaction of the negative ion from a salt with water to produce the ion's conjugate acid and hydroxide ion

basic hydrolysis

Solution where H3O+ < OH-

basic solution

aqueous solution whose pH is greater than 7.0

basic solution

an aqueous solution that contains substances that prevent major changes in solution pH when small amount of acids or bases are added to it

buffers

WHICH IS NOT TRUE: a. CN- reacts with water to produce the conjugate HCN and OH- b. NH4+ reacts with water to produce conjugate NH3 and H3O+ c. Hydrolysis reactions go 100% to completion. d. Blood plasma is slightly basic pH because of salt hydrolysis reactions.

c. - Hydrolysis reactions DO NOT GO 100% to completion; only occur until equilibrium is reached

WHICH IS NOT TRUE: Acidic Hydrogen Atoms a. Not all hydrogen atom in a molecule are acids b. Acidic hydrogen atoms are written first in the formula to differentiate them. c. Number of H atoms present is always used to classify the acid. d. Whether or not a hydrogen atom is acidic is related to the location of bonding between molecules.

c. - Number of H atoms present CANNOT ALWAYS BE used to classify the acid.

WHICH IS NOT TRUE: Titration a. procedure most frequently used to determine the concentration of an acid or a base solution b. concentration of an acid is calculated from original volume of acid, concentration of base, and volume of added base c. a successfully completed titration is where the point at which acid and base have completely reacted with each other is undetectable d. involves a known volume of acid solution placed into a beaker or flask added with a solution of base with known concentration

c. - a successfully completed titration is where the point at which acid and base have completely reacted with each other is DETECTABLE

WHICH IS NOT TRUE: Strength of Acids and Bases a. Acids and bases vary in ability to transfer protons or produce hydronium ions. b. Weak and strong acids are not the same as dilute and concentrated acids. c. Strong and weak acids refer to the amount of electron transfer. d. Dilute and concentrated acids refer to the relative amount of solute in solutions.

c. Strong and weak acids refer to the amount of PROTON transfer.

occurs when the sum of negative ion concentrations and the sum of positive ion concentrations and the sum of positive ion concentrations are equal in mEq/L or Eq/L concentration units

charge balance

WHICH IS NOT TRUE: Acid-base indicators a. Needed because neither acid nor base give outward signs of reaction completion b. Changes color at a pH that corresponds as nearly as possible to the pH of the solution where the titration is complete c. strong acids and strong bases have a pH of 7.0 d. same colors are typically used for basic solutions and acidic solutions

d. - DIFFERENT colors are typically used for basic solutions and acidic solutions

WHICH IS NOT TRUE: Electrolytes a. The presence of charged particles explains electrical conductivity b. Acids, bases, and soluble salts all produce ions in solutions which conduct electricity. c. Weak acids and weak bases are weak electrolytes. d. Soluble salts are weak electrolytes.

d. - Soluble salts are STRONG electrolytes.

WHICH IS NOT TRUE: a. Arrhenius acids in the pure state are covalent compounds without any H+ ions. b. H+ ions are formed through an interaction between water and the acid when they are mixed by ionization. c. Arrhenius bases are ionic compounds in the pure state. d. When dissolved in water, ions of Arrhenius bases separate to yield the H+ ions.

d. - When dissolved in water, ions of Arrhenius bases separate to yield the OH- ions.

WHICH IS NOT TRUE: Acids and Bases a. any chemical reaction involving a Bronsted-Lowry acid must also involve a Bronsted-Lowry base b. hydrogen ions in an aqueous solution do not exist in the free state, but rather, react with water to form hydronium ions (H3O+) c. attraction between H+ and polar H2O molecules is sufficiently strong to bond them and form H3O+ d. the bond between must H+ and H2O molecules is an ionic bond

d. - the bond between must H+ and H2O molecules is a COORDINATE COVALENT bond

WHICH IS NOT TRUE: Buffer Ratios a. the most effective buffer is an acid-to-conjugate-base buffer with a molar concentration is 1-to-1 b. pH of the solution is equal to the pKa of the weak acid in a buffer of 1:1 ratio c. in a buffer without a 1:1 ratio, if there is more A- than HA in the solution, the pH is higher than pKa d. in a buffer without a 1:1 ratio, if there is more HA than A- in the solution, the pH is higher than pKa

d. in a buffer without a 1:1 ratio, if there is more HA than A- in the solution, the pH is LOWER than pKa

acid that can supply only 2H+ per molecule during acid-base reaction

diprotic

process in which individual positive and negative ions are released from an ionic compound that is dissolved in a solution

dissociation

substance whose aqueous solution conducts electricity

electrolytes

produced in the process of self-ionization

equal amounts of hydronium and hydroxide ions

molar amount of an ion needed to supply one mole of positive or negative charge

equivalent of an ion

VARIATION RELAITONSHIP: 1. [H3O+] concentration 2. pH

increase in 1 leads to a decrease in 2

VARIATION RELATIONSHIP: 1. acid strength 2. percent ionization 3. magnitude of Ka

increase in 1 leads to an increase in 2 and an increase in 3

process in which individual positive and negative ions are produced from a molecular compound that is dissolved in solution

ionization