Last modified: Sat 10/26/2013 12:43:49 pm
ACA

Oklahoma State University

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Answer all of the questions below. If you do not know an answer enter CNA. However, it will help me the most if you answer each question with your best intuition/idea about what would be a reasonable answer.


First Name:

Last Name:

Laboratory Section:

1. Write the formula of the salt formed when the following acid and base react. Indicate the acid/base properties of a solution of the salt as either neutral, greater than 7, or less than 7.

Acid

Base

Formula of the salt

Acid base properties

HNO3

KOH

HCl

NH3

HC3H5O2

NaOH

HBr

C6H5NH2

2. For each of the following salts indicate the formula of the anion and the cation in the salt, the formula of the acid and base that had to react to form the salt. Indicate the acid/base properties of a solution of the salt as either neutral, greater than 7, or less than 7. For example:

KCN is a salt: the cation is K+ : the anion is CN-. The acid and base that reacted to form the salt are HCN (a weak acid) and KOH (a strong base). Since K+ comes from a strong base, K+ will not effect the pH of the solution. The anion CN- come from a weak acid, and therefore can effect the pH of the solution. Since CN- is the conjugate base of HCN, it is basic and the pH of the solution will be greater than 7.

Formula of the salt

Cation

Anion

Acid

Base

Acid base properties

KCN

K+

CN-

HCN

KOH

pH is greater than 7

Complete the following table for the two salts.

Formula of the salt

Cation

Anion

Acid

Base

Acid base properties of the salt

KClO

CH3NH3NO3

3. Based on the acid base properties you assigned to KClO and CH3NH3NO3 write the balanced chemical equation that describes the acid base character of the ion that controls the pH of the solution. For the example in 2 we had concluded that CN- controls the pH of the solution, so we can write a chemical equation that describes how CN- behaves as a base.

CN- + H2O HCN + OH-

Write the chemical equation for each salt from Q2:

KClO

CH3NH3NO3

4. Calculate the pH of a 0.100 M KClO solution. (NOTE: Ka (HClO) = 3.0 x 10-8)

pH =

5. Calculate the pH of a 0.100 M CH3NH3NO3 solution. (NOTE: Here is a table of equilibrium constants to help answer this question.)

pH =

6. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

7. If there is one question you would like to have answered in lecture, what would that question be?