# Worksheet: Concentrations from Ionization Constants

In this worksheet, we will practice using dissociation constants to find the equilibrium concentrations of undissociated acids and bases.

**Q1: **

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

**Q2: **

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

**Q3: **

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

- A
- B
- C
- D

**Q4: **

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

**Q5: **

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

**Q6: **

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

**Q7: **

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.

**Q8: **

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

- A
- B
- C
- D
- E1.07

**Q9: **

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

- A
- B
- C
- D
- E

**Q10: **

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

- A
- B
- C
- D
- E

**Q11: **

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

- A
- B0.10
- C
- D
- E

**Q12: **

Using the equilibrium concentrations

and

what is the value of for ?

- A
- B
- C
- D
- E

**Q13: **

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

**Q14: **

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

**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 ? of is .

- A M
- B 0.12 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: **

What is the concentration of in at ? of is .

- A 0.078 M
- B M
- C M
- D M
- E M

**Q19: **

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

- A M
- B M
- C M
- D M
- E M

**Q20: **

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

- A
- B0.29
- C
- D
- E

**Q21: **

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

**Q22: **

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