Chemistry chpt 11 (Princeton review)

signs for delt G and E when a galvanic cell spontaneously generates electrical power

- delta G and positive E

What is the pH of a solution with a hydronium ion concentration [H_3 O^+] = 10^4[H3​O+]=104open bracket, H, start subscript, 3, end subscript, O, start superscript, plus, end superscript, close bracket, equals, 10, start superscript, 4, end superscript M

-4 pH=-log[H30+]

-log of 0..01

2

example [H+]=6.2 x 10^-5 what is the pH between

4-5 between n-1 and n subtracting from the exponent think of equation [H+]= 10^-pH acidic

Suppose a nanotechnological innovation allows every single charged ion to be precisely identified and removed from a small volume of water. Which of the following describes K_aKa​K, start subscript, a, end subscript for the water at the end of the process, assuming that the filtered water is given adequate time to re-equilibrate? Choose 1 answer:Choose 1 answer: (Choice A)A10^{-14}10−1410, start superscript, minus, 14, end superscript (Choice B 10^{-7}10−710, start superscript, minus, 7, end superscript (Choice C)C1 (Choice D)D0

The autoionization of water occurs naturally due to attractive forces between constituents of water molecules. Hint #22 / 3Even if all ions are removed from a sample of water (including hydronium ions), a short time later the water will re-ionize until it approaches an equilibrium concentration of ions. Hint #33 / 3In equilibrium, K_a = K_w = 10^{-14}Ka​=Kw​=10−14

calculating standard reduction potentials

add the voltage given never add the coefficients to the voltage because that is wrong if going opposite way just switch sign if you get a not spontaneous outcome it would be spontaneous if it were going the opposite direction.

salt bridge anions migrate towards______ salt bridge cations migrate towards_______

anode cathode

electrons always flow from ____ to _____

anode to cathode

what is the autoionization of water

at 25C its kw=1.0 x 10^-14 varies with temperature increases with increasing temperature in this state OH- and H0+ are in equal concentrations which is 1.0 x 10^-7M Kw is regardless of the H30+ concentration

amphoteric

can act as an acid and base conjugate base of a weak polyprotic acid is always amphoteric water is amphoteric so is H2CO3 (carbonic acid)

free energy of an electrochemical cell can be calculated from its potential based on

delta G ^ not = -nFE^not

equation to determine if a redox reaction is spontaneous

delta G ^not = - nFE^not not = standard conditions 25C 1 atm 1M aqueous concentration I

strong acid

dissociates completely or almost in water

of the following which acid has the weakest conjugate base HCLO4 HCOOH H3PO4 H2CO3

find the strongest acid which is HClO4

example what is the pH of a solution at 25C whose hydroxide ion concentration is 1 x 10^-4M

first we know how to find pOH pOH = -log[1 x 10 ^-4] pOH = 4 4 + pH = 14 so pH = 10

ionization

forming a cation from a neutral atom or an anion gaining a charge

greater concentration of H+ ions the _____ concentration of OH- ions

lower

polyprotic

more than one proton to donate the second reaction or the second proton donated will always be a weaker acid than when it let go of the first

in electrochemical cells _____ occurs at the anode and _____ occurs at the cathode

oxidation reduction

relationship of OH- and H+

pH + pOH=14 since [H+][OH-]=10^-14 at 25C

pH formula

pH=-log[H+] or [H+]=10^-pH [H+] is also [H3O+]

relationship between Ka and pKa or Kb and pKb

pKa = -log of Ka pKb = -log of Kb

PkA to Ka

pKa=-logKa

pOH formula

pOH=-log[OH-] or [OH-] = 10^-pOH

equation for pka + pkb

pka + pkb = 14

conjugate base of strong acid

reaction goes to completion so no reverse reaction conjugate base of strong acid has no basic properties it wont accept a proton

species that is oxidized is a ______ agent species that is reduced is a ______ agent

reducing oxidizing

weaker the acid the more the ______ reaction is favored and the stronger the_____

reverse conjugate base Ex: if you have an acid with a Ka smaller than another that conjugate base will be stronger than the stronger acid conjugate base will be If you have a very weak acid the reverse reaction will be favored so the conjugate base will be stronger

Spontaneous or not if cell voltage is positive _____ if cell voltage is negative_____

spontaneous not spontaneous

conjugate acid of strong and weak base

strong base no conjugate acid or no acidic properties weak base is a weak acid weaker the base the stronger the conjugate acid

what does pH measure

the OH- or H3O+ concentration

strong acids how does the molarity help you calculate the pH

the molarity is directly related to the pH so 0.01M soluction of HCl will have [H+] = 0.01M and pH=2 it will completely dissociate until hydrogen ion concentration is the same as concentration of acid

example of the following anions which is the strongest base

to go about this look for the weakest acid and that will have the strongest base

bronstead lowery acid and base

acid = proton donor must have an H base = proton acceptors any anion or neutral species with a lone pair of electrons can function as a base

Ka

acid dissociation constant if >1 products are favored so the acid would be strong if Ka is <1 acid is weak reactants are favored larger Ka mean stronger acid smaller Ka weaker acid opposite for pKA

Lewis acid and base

acid electron pair acceptor base electron pair donor

Which of the following describes the pH of an equilibrated, stoichiometric mixture of ammonia, NH_3NH3​N, H, start subscript, 3, end subscript and hydrochloric acid HClHClH, C, l Choose 1 answer:Choose 1 answer:(Choice A, Incorrect)pH > 7pH>7p, H, is greater than, 7 (Choice B, pH \approx 7pH≈7p, H, approximately equals, 7 (Choice C, pH < 7pH<7p, H, is less than, 7 (Choice D pH = 4pH=4p, H, equals, 4

Ammonia is a weak base Hint #22 / 5Hydrochloric acid is a strong acid Hint #33 / 5The hydrochloric acid will donate a proton to the ammonia to form ammonium, NH_4^+NH4+​N, H, start subscript, 4, end subscript, start superscript, plus, end superscript Hint #44 / 5Ammonium reacts with water to form hydronium, NH_4^+ + H_2 O \rightarrow NH_3 + H_3 O^+NH4+​+H2​O→NH3​+H3​O+N, H, start subscript, 4, end subscript, start superscript, plus, end superscript, plus, H, start subscript, 2, end subscript, O, right arrow, N, H, start subscript, 3, end subscript, plus, H, start subscript, 3, end subscript, O, start superscript, plus, end superscript Hint #55 / 5A mixture of a strong acid and a weak base acquires an overall acidic pH < 7pH<7

what are the strong bases

Group 1 hydroxides LiOH, NaOH, KOH, Group 1 oxides Li2O etc. Group 2 hydroxides Ca(OH)2, Sr(OH)2, Ba(OH)2 Metal amides ammonia

KNOW Which of the following best describes a chemical species that is measured to have K_b = 3.2\times10^{-18}Kb​=3.2×10−18K, start subscript, b, end subscript, equals, 3, point, 2, times, 10, start superscript, minus, 18, end superscript? weak base strong base weak acid strong acid

Whether a chemical is an acid or base depends on whether K_aKa​K, start subscript, a, end subscript or K_bKb​K, start subscript, b, end subscript is greater. Hint #2 Because K_a K_b = K_w = 10^{-14}Ka​Kb​=Kw​=10−14K, start subscript, a, end subscript, K, start subscript, b, end subscript, equals, K, start subscript, w, end subscript, equals, 10, start superscript, minus, 14, end superscript, for this chemical K_a = 3.125 \times 10^3Ka​=3.125×103K, start subscript, a, end subscript, equals, 3, point, 125, times, 10, cubed, suggesting that it is an acid. Hint #33 / 3Because K_a \gg 1Ka​≫1K, start subscript, a, end subscript, \gg, 1, the species is known as a strong acid.

what is [H+] for water

[H+]=10^-7M

Suppose an equilibrated, dilute solution containing an acid HAHAH, A with K_a = 10^{-4}Ka​=10−4K, start subscript, a, end subscript, equals, 10, start superscript, minus, 4, end superscript is measured to have pH = 6pH=6p, H, equals, 6 and [HA] = 10^{-8}[HA]=10−8open bracket, H, A, close bracket, equals, 10, start superscript, minus, 8, end superscript M. Which of the following gives the best estimate of [A^-][A−]open bracket, A, start superscript, minus, end superscript, close bracket Choose 1 answer::(Choice A)A10^{-4}10−410, start superscript, minus, 4, end superscript M (Choice B)B10^{-6}10−610, start superscript, minus, 6, end superscript M (Choice C)C10^{-14}10−1410, start superscript, minus, 14, end superscript M (Choice D,)10^{-12}10−1210, start superscript, minus, 12, end superscript M

henderson-hasselbalch equation pH=pKa + log ([conjugate base]/[conjugate acid])

Low pH means _____[H+] and soln is ______

high [H+] acidic if [H+] is greater than 10^-7 pH will be less than 7 and is acidic if [H+] is less than 10^-7 pH will be higher than 7 and is basic

Kb

higher Kb means stronger base

the strength of an acid is directly related to___

how much the products are favored over the reactants.

name the strong acids

hydroiodic acid HI hydrobromic acid HBr Hydrochloric acid HCl Perchloric acid HClO4 Sulfuric acid H2SO4 Nitric acid HNO3 Ka is so large any acid not not on this list is a weak acid

acids and bases are ______ related

inversley

- log of 1 x 10^-5

is 5 if you have 1 x 10 to whatever it equals that number

conjugate base of weak acid

is a weak base

Ka and Kb for any acid conjugate base pair

it will be Kw=1 x 10^-14 if you look at page 239 you will see how everything else cancels out and it ends up being [H30+][OH-] so Ka x kb = kw = 1 x 10^-14 so if you are given a Ka or Kb just plug into ka x kb=1 x 10^-14