Last modified: Wed 03/09/2016 06:09:30 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.


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1. The chemical equation that describes how HCl(aq) behaves as an Bronsted-Lowry acid is

HCl(aq) + H2O(l) H3O+(aq) + Cl-(aq)

In this reaction HCl donates a proton to H2O, as evidenced by the presence of Cl-(aq) as a product (HCl must donate a proton to become Cl-) and H3O+(aq) (H2O must accept a proton to become H3O+). So identifying everyone in the reaction as an acid or base in Bronsted-Lowry terms,

HCl(aq)

+ H2O(l)

H3O+(aq)

+ Cl-(aq)

acid

base

 

conjugate acid

conjugate base

For each of the following acids write the Bronsted-Lowry equation that describes its acidic character. (NOTE: It is a little difficult to represent the equilibrium arrow online so using a ---> (three '-' dashes and a '>' greater than character is fine. Just remember for weak acids the equilibrium symbol is best for representing the reaction arrow.)

a) HClO4(aq)

b) HC2H3O2(aq)

c) CH3NH3+(aq)

2. The chemical equation that describes how NH3(aq) behaves as an Bronsted-Lowry base is

NH3(aq) + H2O(l) NH4+(aq) + OH-(aq)

In this reaction NH3 accepts a proton to H2O, as evidenced by the presence of NH4+(aq) as a product (NH3 must accept a proton to become NH4+) and OH-(aq) (H2O must donate a proton to become OH-). So identifying everyone in the reaction as an acid or base in Bronsted-Lowry terms,

NH3(aq)

+ H2O(l)

NH4+(aq)

+ OH-(aq)

base

acid

 

conjugate acid

conjugate base

For each of the following bases write the Bronsted-Lowry equation that describes its basic character.

a) Cl-(aq)

b) HCO3-(aq)

3. Complete the following table by calculating the value of the missing entry. (NOTE: To express a number in scientific notation 1.00 x 10-7, enter the value as 1.00e-7.)

[H+]

[OH-]

pH

pOH

5.50 x 10-5 M

M

M

7.06 x 10-9 M

M

M

2.10

M

M

6.33

4. Calculate the pH of 0.250 M HC2H3O2 solution. pH =

5. Calculate the pH of 0.250 M NH3 solution. 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?