Ch 16 Review Answers #2-13

1. Study definitions from homework and notes. amphoteric, buffered solution, Arrhenius acid-base, Bronsted Lowry acid/base, strong acid/base, indicator equivalence point, titrant

2. Write the conjugate acid. For all acids, add H and 1 positive charge

a. SO₃ ^2-                 b. HS^-              c. F^-

HSO₃ ^-                 H₂S              HF

      3.   Write the conjugate base. For all bases, take off 1 H and add 1 negative charge

            a. H₂SO₄          b. H₂CO₃         c. HC₂H₃O₂

                HSO₄^-          HCO₃^-              C₂H₃O₂^-

4. Write the formula for common strong and weak acids.

            Strong H₂SO₄     HCl    HBr    HI     HClO₄      HNO₃   

             Weak: HF, HC₂H₃O₂                                      Any acid with carbon is a weak acid.

5. Explain how to classify a solution as neutral, acidic or basic by its concentration of H⁺ and OH^-.

Acidic [H+] >[OH-];          Basic [OH-] > [H+] ;               Neutral [H+] = [OH-];

6. Calculate the concentration of H⁺ or OH^- . Hint: Use the equation for K_w.

a. 1.0 x 10^-7 M OH^-     b. 0.1 M H⁺

            K_w =  [H+] [OH-]                               K_w =  [H+] [OH-]

            1.0 x 10^-14 = [H+] [1.0 x 10^-7]             1.0 x 10^-14  = [H+] [1.0 x 10^—1]

            [1.0 x 10^-7]            [1.0 x 10^-7]              1.0 x 10⁺¹             1.0 x 10^-1

            1.0 x 10^-7 = [H+]                                 1.0 x 10^-13 = [H+]      

7. Classify the solutions as acidic or basic. Which solution is more acidic?

a. pH 12.4       b. pH 3.5         c. pH 1.0

                basic                acidic              acidic                        C is most acidic

8. What is a buffered solution? What is present in a buffered solution? Give an example. A buffered solution resists a change in pH when acids or bases are added to the solution. A weak acid and its conjugate base are present in a buffered solution. HC₂H₃O₂ and NaC₂H₃O₂

9.   pH + pOH = 14   Use this equation to calculate the following.

      a. pOH = 8.90             b. pH = 1.81

      14 - 8.90 = 5.10                      14 – 1.81 = 12.19

10. What products are formed when a strong acid is added to a strong base?

Neutralization reactions produce a salt and water

11. What are the 3 ways to measure pH?

Indicators, pH meter, litmus

12. A low pH has a ________ concentration of H⁺.

a. high              b. low              c. neutral

13. Explain the difference between a strong acid and a weak acid in aqueous solution.

A strong acid dissociates (ionizes) completely and a weak acid partially dissociates (ionizes)