# Worksheet: Concentrations from Ionization Constants

Q1:

Consider the equilibrium for the ionization of trimethylamine, a weak base:

The of trimethylamine is . Assuming the effect of dissociation on the trimethylamine concentration is negligible, calculate the concentration of hydroxide ions in a 0.25 M trimethylamine solution.

• A M
• B M
• C M
• D M
• E M

Q2:

What is the concentration of in at ? of is .

• A M
• B 0.12 M
• C M
• D M
• E M

Q3:

A 0.134 M solution of the diprotic acid contains , . Which two of these species are present in almost equal concentrations?

• A
• B
• C
• D
• E

Q4:

What is the hydronium ion concentration in a 0.100 M solution of ammonium nitrate, , a salt composed of the ions and ? of ammonia is .

• A M
• B M
• C M
• D M
• E M

Q5:

For which of the following solutions must we consider the ionization of water when calculating the pH or pOH?

• A in 1.0 L of solution
• B
• C in 0.10 L of solution
• D
• E

Q6:

Acetic acid is the principal ingredient in vinegar. In a sample of vinegar at equilibrium, and . What is the value of for acetic acid?

• A
• B
• C
• D
• E

Q7:

In a hypochlorous acid solution at equilibrium, , and . Calculate to 3 significant figures the value of for .

• A
• B
• C
• D
• E

Q8:

The ionization constant of lactic acid, , an acid found in blood after strenuous exercise, is . If 15.0 g of lactic acid is used to make a solution with a volume of 1.00 L, what is the concentration of hydronium ions in the solution?

• A M
• B M
• C M
• D M
• E M

Q9:

When dissolves in water, ions are formed. The ion acts as a monoprotic acid with a value of . Calculate the concentration of ions in a 0.15 M solution of if the concentration of ions is 0.10 M.

• A M
• B M
• C M
• D M
• E M

Q10:

Using the equilibrium concentrations and what is the value of for ?

• A
• B0.10
• C
• D
• E

Q11:

Propionic acid, () is used in the manufacture of calcium propionate, a food preservative. Calculate to 2 significant figures the hydronium ion concentration in a 0.712 M solution of .

• A M
• B M
• C M
• D M
• E M

Q12:

Using the equilibrium concentrations

and

what is the value of for ?

• A
• B
• C
• D
• E

Q13:

In a trimethylamine solution at equilibrium, and . Calculate the value of for trimethylamine.

• A
• B0.29
• C
• D
• E

Q14:

What is the concentration of in at ? of is .

• A 0.078 M
• B M
• C M
• D M
• E M

Q15:

What is the concentration of in a 0.0092 M aqueous solution of hypochlorous acid at ? The of hypochlorous acid is .

• A 0.0092 M
• B M
• C M
• D M
• E M

Q16:

What is the concentration of in at ? The of is .

• A M
• B M
• C M
• D M
• E M

Q17:

What is the concentration of in at ? of is .

• A M
• B 0.081 M
• C M
• D M
• E M

Q18:

Consider the equilibrium

What is the equilibrium acetic acid concentration in a solution where and at equilibrium? The of acetic acid is .

• A M
• B M
• C M
• D M
• E M

Q19:

Caffeine, , is a weak base. What is the value of for caffeine if a solution at equilibrium has and

• A
• B
• C
• D

Q20:

In a solution of acetic acid at equilibrium, , and . What is the value of for ?

• A
• B
• C
• D
• E

Q21:

In an aqueous solution at equilibrium, . Calculate the value of for .

• A
• B
• C
• D
• E1.07

Q22:

When dealing with acid and base solutions, when is it necessary to use equilibrium calculations to accurately determine equilibrium concentrations?

• AWhen the temperature is not .
• BIn nonaqueous systems.
• CWhen a strong acid or base is involved.
• DWhen a weak acid or base is involved.
• EOnly at very low concentrations.