Chem 210 Exam 1 – 3 Latest Updated 2024

Chem 210 Exam 1 – 3 Latest Updated 2024

Salt is the product of what rxn? - ANSWER-Acid-base
usually strong electrolytes that completely dissociate in water


Strong acid - strong acid
strong acid - weak base
strong base - strong base
weak acid - weak base


Calculate the pH of 0.010 M solution of sodium hypochlorite (NaClO) The Ka
is 2.9 x 10^-18 - ANSWER-Kw = Kb x Ka


Kb = Kw/ka


kb = 3.45 x 10^-7


R ClO- + H2O <=> OH- + HClO
I 0.010

,C-X+X+X
E 0.010 - X X X


0 = X^2 - 3.45 X 10^-7 X + 3.45 X 10^-9


quadratic eq.


x = 5.86 x 10^-5 = [OH]


-log[OH] = pOH


pH = 14 - pOH


pH = 9.77


What eq. are useful when working with weak acids and bases? - ANSWER-
HA <=> H+ + A-


ka = [H][A]/[HA]

,B + H2O <=> BH + OH


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


Calculate [H3O], pH, [HA], [A-], [OH], and alpha of .100 M propanoic acid
(CH3CH2CO2H)


pKa = 4.87 Ka = 1.34 x 10^-5 - ANSWER-HA (aq) + H2O <-> H3O + A-


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Ka = [H3O][A]/[HA] =
x^2 /(F-x)


[H3O] = [A-] = x


1.34 x 10^-5 = x^2 /(0.010-x)

, quadratic eq.


x = 1.151 x 10^-3 = [H3O]


pH = -log(H3O) = 2.94


pOH = 14 - 2.94


[A-] = [H3O]


[HA] = F - x = 0.01 - 1.151 x 10^-3


alapha = x/ F (100) = 1.151 x 10^-3/.01 (100)


Calculate the [OH], [H3O], pH [BH], [B], and alpha of 0.1 M CH3NH2 Ka =
2.31 x 10 -11 - ANSWER-B (aq) + H2O <-> BH + OH-


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