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Chemistry – Unit 11 Worksheet #2
Acid & Base Strength, Concentration, & pH
Answer the following questions on your own paper.
You may want to reference your notes/book to review relevant relationships
1.
Answer the following questions about nitric acid, which is classified as a strong acid:
a) Write the dissociation reaction for nitric acid with water. How would you describe the extent of ionization
for this acid? Explain.
b) Verbally describe what the term “strong” means about nitric acid. What does this reveal about the
conjugate base’s ability to attract protons?
c) Illustrate these concepts by drawing a particle diagram of an aqueous solution of nitric acid.
2.
Answer the following questions about ammonia, which is classified as a weak base:
a) Write the dissociation reaction for ammonia with water. How would you describe the extent of ionization
for this base? Explain.
b) Verbally describe what the term “weak” means about ammonia. What does this reveal about the base’s
ability to attract protons?
c) Illustrate these concepts by drawing a particle diagram of an aqueous solution of ammonia.
3.
What does it mean to say that an acid is weak in aqueous solution? What does this reveal about the ability of
the acid’s anion to attract protons?
4.
Which is a stronger acid, 0.50 M HCl or 2.0 M HF? Which acid is more concentrated?
(Hint: Draw particle diagrams if you struggle with this one!)
5.
Write the chemical formulas for the six strong acids. For ONE of these write the equation showing the acid
dissociating in water. Is a single or double arrow used in the reaction? Why?
6.
Describe conceptually what the pH of a solution measures. Then describe how is pH defined
mathematically (and provide an equation).
7.
What is the pH of pure water? Why?
8.
What range of pH values indicate an acidic solution? A basic solution? Why can the pH scale still be used
to measure bases if it is based on the hydronium ion concentration?
9.
As the hydrogen ion concentration of a solution increases, does the pH of the solution increase or decrease?
10. For each of the hydrogen ion concentrations listed, calculate the pH of the solution. Indicate whether the
solution is acidic or basic.
c. a 0.050 M HNO3 solution
a. [H3O+] = 1.0 x 10-3 M
d. a 2.0 M HCl solution
b. [H3O+] = 1.25 x 10-12 M
11. Calculate the hydrogen ion concentration in molarity for solutions of the following pH values.
a. pH = 6.00
c. pH = 1.04
b. pH = 13.10
d. pH = 8.62
Modeling Chemistry
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U14 ws 2 v1.5