Part 1 --Acid-Base Equilibria Flashcards by amanda kastel

According to the Arrhenius Theory (1887), what is the definition of an acid and what is the definition of a base?

acid – A substance that liberates (releases) hydrogen ions

base – A substance that supplies (releases) hydroxyl ions

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what is the name of the modern theory of acids and bases?

the Bronsted-Lowry theory

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According to the Bronsted-Lowry theory, give the definition of an acid and a base

acid – a substance, CHARGED OR UNCHARGED, that is capable of donating a proton

base – a substance, CHARGED OR UNCHARGED, that is capable of accepting a proton from an acid

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according to the modern theories of acids and bases, define “strong acid” and “weak acid”

give a specific example of each

strong acid – high tendencies to give up protons
ex: HCl in water

weak acid – low tendencies to give up protons
ex: acetic acid (CH3COOH) in water

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the modern theory of defining strong acids and strong bases is _____ dependent

explain how acetic acid and hydrochloric acid could either be strong or weak acids given this statement

SOLVENT dependent

as mentioned, HCl is a strong acid in WATER. however, when placed in glacial acetic acid, it has WEAK acid properties. It has a low tendency to donate its proton

As mentioned, acetic acid is a weak acid in WATER. however, when placed in liquid ammonia, it has STRONG acid properties — high tendency to donate its protons

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according to the modern theories of acids and bases, name and explain 2 classes of solvents

protophilic solvent (basic)
protogenic solvent

protophilic solvent — capable of accepting protons from the solute

protogenic solvent – a proton-donating compound (acids)

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give 3 examples each of protophilic and protogenic solvents

protophilic solvents – acetone, ether, liquid ammonia

protogenic solvent – represented by ACIDS: acetic acid, sulfuric acid, hydrochloric acid

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_____ solvents are also known as basic solvents

protophilic

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what is a “protolytic reaction”?

reactions involving transfer of one or more protons

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give an example of a protolytic reaction

give the full formula and identify the acid and base as well as conjugate pairs

HCl in water

HCl + H2O —> H3O+ + Cl-

acid = HCl
base = H2O

conjugate pair: HCl and Cl- & H2O and H3O+

notice: SINGLE HEADED ARROW. complete ionization.

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HCl + H2O —> H3O+ + Cl-

this is complete ionization due to _______. There is no _____ in the final solution

this is complete ionization due to the SINGLE HEADED ARROW and the fact that HCl is a strong acid

there is NO HCl in the final solution. complete ionization occurred

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there are ___ types of protolytic reactions.
name them

4 types:

ionization
neutralization
hydrolysis
displacement

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according to the Lewis Electron Theory, define an acid and a base

acid – a molecule or ion that accepts an electron pair to form a covalent bond

base – the substance that provides the pair of unshared electrons by which the base coordinates with the acid

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According to the Lewis Electron theory, the substance that PROVIDES the electron pair is the base or the acid?

base

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define equilibrium

a balance between 2 opposing forces or actions

rate of forward reaction = rate of reverse reaction

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differentiate between the pH conditions in the stomach and in the small intestine

stomach environment is much more acidic than small intestine environment

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True or false

water is a base

false – water can act as an acid or a base depending on what it’s reacting with

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give the formula for acetic acid in water and identify the acid and the base, as well as conjugate pairs

CH3COOH + H2O <—–> H3O+ + CH3COO-

acid = acetic acid
base = water

conjugate pairs:
CH3COOH and CH3COO-
H2O and H3O+

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Give the formula for RATE of the FORWARD reaction of Acetic Acid in Water

Rf = k1 * [CH3COOH] * [H2O]

in general —-
rate of forward reaction is proportional to the concentration of the REACTANTS

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Give the formula for the RATE of the REVERSE reaction of Acetic Acid in water

kr = k2 * [H3O+]^1 * [CH3COO-]^1

in general – rate of reverse reaction is proportional to the concentration of the PRODUCTS

^1 indicates 1 mole of that compound in reaction

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at equilibrium, ___ = ____

Rf = Rr

aka……

k1 * [CH3COOH]^1 * [H2O]^1 = k2 * [CH3COO-] * [H3O+]

___ is the symbol for the dissociation constant of a weak acid

k=…………………. (assume acetic acid in water)

k = [H3O+][CH3COO-]/[CH3COOH][H2O]

Ka =……

the dissociation constant of a weak acid

[H3O+][CH3COO-]/[CH3COOH]

why is water not in the formula for dissociation of a weak acid? (Ka)

water is in enough excess to be assumed as a constant

is HAc representing the ionized or unionized form of acetic acid?

unionized ionized is Ac-

give 3 equations for dissociation constant of weak acid (Ka) (assume acetic acid in water)

Ka = [CH3COO-][H3O+]/[CH3COOH] Ka = x^2/(c-x) ka= x^2/c

true or false all salt forms can undergo complete ionization

false -- most salt forms

name 2 formulas for dissociation concentration of a weak acid

x^2 = Kac x = [H3O+] = square root of Kac

give formula for a non-ionized weak base in water

B + H2O <-----> OH- + BH+

give the dissociation constant for the ionization of weak bases in water

Kb = [OH-][BH+]/[B]

give the dissociation concentration formula for weak bases

[OH-] = square root of Kbc

give the formula for sodium acetate

Na+ CH3COO-

water can either be....

a weak acid or a weak base

when you increase the temperature, what happens to the rate of the reaction?

the rate of the FORWARD reaction is increased. -higher dissociation -favors product formation

why do we normally not mess with temperature too much to increase the rate of dissociation?

requires complicated storage for the product to remain at that temp

What are "monoprotic electrolytes"

acids that donate a single proton and bases that accept a single proton

what are "polyprotic electrolytes"

acids/bases that are capable of donating/accepting two or more protons

what is the term for an electrolyte that can accept/donate 2 protons? What about 3? give examples

diprotic or dibasic diprotic acid = carbonic acid triprotic or tribasic triprotic acid = phosphoric acid

give the formula for phosphoric acid

H3PO4

what is the term for a species that can function as either an acid or a base?

an AMPHOLYTE

what is neutral pH? what is [H3O+] and [OH-] at this pH?

neutral pH is 7 both [H3O+] and [OH-] are 10^-7moles/L

pKw =

14 ALWAYS

pH + pOH = .......

pKw

pKa + pKb = .......

pKw

pK is a _____ exponent

dissociation

how to find the hydrogen ion concentration [H3O+] of a weak acid?

[H3O+] = square root of Kac

how to find the hydroxyl ion concentration [OH-] of a weak base?

[OH-] = square root kbc

what is the sulfuric acid formula

H2SO4

pKa = ......

-log Ka

what is Ka?

dissociation constant