I need answers for 5, 8, 9, 13 and 14 acid and base pH lab report vT) Calculate

ID: 521216 • Letter: I

Question

I need answers for 5, 8, 9, 13 and 14

acid and base pH lab report

vT) Calculate the pH of a solution whose IH -0.00814 M. 5.30 2) Calculate the [H of a solution whose pH 8.48 3) Which of the solutions tested are acidic? Basic? v 4 Each acid had a concentration of 0.10 M. Compare the concentration of the H ion in each soiution. Are they constant o ne sowy,an as aeny te mere H. concen 5 From the pH, calculate the concentration of hydrogen ion. Next find the concentration of the acetate ion. Next determine the actual concentration of acetic acid that is in solution. Show one set of sample calculations [C2H3 3.3 u 0.10 M acetic acid 0.010 M acetic acid. 0.0010 M acetic acid HL 0.00010 M acetic acid Zu 6) What general pattern do you observe in the concentration of acetic acid versus pH? The less the concentration of aces c aci d Hee the ucidity become

Explanation / Answer

5) The dissociation of acetic acid (CH3CO2H) can be shown as:

HC2H3O2 (aq) ---------> C2H3O2- (aq) + H+ (aq)

At equilibrium, we will assume the molar concentrations of C2H3O2- and H+ are equal, i.e, [C2H3O2-] = [H+]. This is due to the 1:1 nature of dissociation of acetic acid.

The equilibrium constant for the dissociation reaction is the acid-dissociation constant, Ka and is given as

Ka = [C2H3O2-][H+]/[CH3CO2H]eq = 1.76*10-5 at 25C …..(1)

Consider the first entry, pH = 3.34.

We define pH of a solution as pH = -log [H+]; therefore, [H+] = antilog (-pH) = antilog (-3.34) = 4.57*10-4 M.

Therefore, [H+] = 4.57*10-4 M and as per our definition of acid-dissociation constant, [CH3CO2-] = 4.57*10-4 M.

Plug in the values in (1) and obtain [CH3CO2H]eq.

1.76*10-5 = (4.57*10-4)*(4.57*10-4)/[CH3CO2H]eq

====> [CH3CO2H]eq = (4.57*10-4)2/(1.76*10-5) = 0.01187.

Therefore, the equilibrium concentration of acetic acid is 0.0119 M.

Fill up the table now:

[H+] (M)

[C2H3O2-] (M)

[HC2H3O2] (M)

0.10 M acetic acid

3.34

4.57*10-4

0.01187

0.010 M acetic acid

3.89

1.29*10-4

9.455*10-4

0.0010 M acetic acid

4.41

3.89*10-5

8.598*10-5

0.00010 M acetic acid

4.89

1.29*10-5

9.455*10-6