CHM 113 FINAL STUDY GUIDE
QUESTIONS & ANSWERS 100%
ACCURATE
What is the [H+] of a solution with a pH of 3.78? - ANSWER14 - pOH = pH
pH = 3.78
[H+] = 10^3.78
= 1.66 x 10^-4
If HX represents the formula of a weak acid, what is the formula of the conjugate
base of HX? - ANSWERIf HX weak acid then the formula of the conjugate base of X-
Let HX represent the formula of a weak acid. Write a balanced chemical equation for
the reaction of this weak acid with the strong base NaOH? You may omit any
spectator ions if you wish. - ANSWERHX + NaOH --> NaX + H2O
If a weak acid, HX, is titrated with a strong base such as NaOH, will the equivalence
point in the titration occur below pH 7.0, at pH 7.0 or above pH 7.0? - ANSWERthe
equivalence point in the titration will be somewhat above pH 7.0
A student is presented with a 0.65 M solution of an unknown weak acid. The student
measures the pH of that solution and determines a value of 3.78 for the unknown
solution. What, then, is the Ka of this weak acid? - ANSWERKa = [(1.66 x
10^-4)^2]/(.65 - 1.66 x 10^-4) = 4.2 x 10^-8
Regarding today's experiment, what is the weak acid we are going to titrate and
which strong base is used to titrate this weak acid? - ANSWERWeak Acid: Acetic
Acid
Strong Base: NaOH
What is the pH of a weak acid whose Ka is 6.03 x 10^-6, and the ratio of [A-]/[HA] is
3. - ANSWER6.03x10^-6 = [H3O+][9]/3
pH = 5.69
What is the acid dissociation constant (Ka)? - ANSWERKa = [H30+][A-]/[HA]
For the equation you wrote above, what two terms are considered/assumed equal? -
ANSWER[HA] = [A-]
QUESTIONS & ANSWERS 100%
ACCURATE
What is the [H+] of a solution with a pH of 3.78? - ANSWER14 - pOH = pH
pH = 3.78
[H+] = 10^3.78
= 1.66 x 10^-4
If HX represents the formula of a weak acid, what is the formula of the conjugate
base of HX? - ANSWERIf HX weak acid then the formula of the conjugate base of X-
Let HX represent the formula of a weak acid. Write a balanced chemical equation for
the reaction of this weak acid with the strong base NaOH? You may omit any
spectator ions if you wish. - ANSWERHX + NaOH --> NaX + H2O
If a weak acid, HX, is titrated with a strong base such as NaOH, will the equivalence
point in the titration occur below pH 7.0, at pH 7.0 or above pH 7.0? - ANSWERthe
equivalence point in the titration will be somewhat above pH 7.0
A student is presented with a 0.65 M solution of an unknown weak acid. The student
measures the pH of that solution and determines a value of 3.78 for the unknown
solution. What, then, is the Ka of this weak acid? - ANSWERKa = [(1.66 x
10^-4)^2]/(.65 - 1.66 x 10^-4) = 4.2 x 10^-8
Regarding today's experiment, what is the weak acid we are going to titrate and
which strong base is used to titrate this weak acid? - ANSWERWeak Acid: Acetic
Acid
Strong Base: NaOH
What is the pH of a weak acid whose Ka is 6.03 x 10^-6, and the ratio of [A-]/[HA] is
3. - ANSWER6.03x10^-6 = [H3O+][9]/3
pH = 5.69
What is the acid dissociation constant (Ka)? - ANSWERKa = [H30+][A-]/[HA]
For the equation you wrote above, what two terms are considered/assumed equal? -
ANSWER[HA] = [A-]
