4/15 HW ANSWERS – Acid/Base Review

 

42.  According the Arrhenius, what are the characteristics of acids and bases?

They are both electrolytes, which means they conduct an electric current in solution. An acid produces H+ in solution. A base produces OH- in solution.

 

43.  How do hydronium ions form? Why do they form in aqueous acid solution?

They form when an acid breaks apart in solution forming ions (H+ and an anion), the hydrogen ions join with the water to form hydronium ions.

 

45.  For each of the following reactions, label the acid, base, conjugate acid, and conjugate base.

       a.    NH3 (g) +     H3O+ (aq) à       NH4+ (aq) + H2O (l)

              Base             Acid             CA        CB

       b.    CH3OH (l) + NH2- (aq) à CH3O- (aq) +       NH3 (g)

              Acid             Base             CB         CA

       c.    OH- (aq) +    H3O+ (aq) à       H2O (l) +      H2O (l)

              Base             Acid             CA (or CB)  CB (or CA)

       d.    NH2- (aq) +  H2O (l) à    NH3 (g) +     OH- (aq)

              Base             Acid             CA        CB

 

46.  How do binary acids and ternary acids differ?

       A binary acid has only two elements and a ternary acid has three elements.

 

49.  What element is always present in binary acids? What two elements are usually present in ternary acids?

       Binary acids always have HYDROGEN.

       Ternary acids usually have HYDROGEN and OXYGEN

 

54.  Why do we call an aqueous solution of HCl strong and a solution of acetic acid weak?

HCl completely ionizes in solution and acetic acid does not break apart in solution. More ions, stronger acid.    

 

55.  In writing net ionic equations, why are insoluble salts not written as ions?

       They do not break apart in solution, they stay solid.

 

60.  Name the following acids.

       a.    HI

              hydroiodic acid

b.              H2TeO3

Tellurous acid

c.               H2Se

Hydroselenic acid

d.              HIO3

Iodic acid

 

61.  Write formulas for the following acids.

       a.    phosphorous acid

              H3PO3

c.               hydrotelluric acid

H2Te

d.              periodic acid

HIO4

e.               iodic acid

HIO3

f.                hydrochloric acid

HCl

 

70.  Give the names and formulas of the salts obtained from complete neutralization reactions between the following acid-base pairs.

       a.    sodium hydroxide + phosphoric acid à      sodium phosphate + water

                                                       Na3PO4

 

b.              potassium hydroxide + boric acid, H3BO3 àpotassium borate + water

K3BO3

 

c.               cadmium hydroxide + hydrobromic acid à       cadmium bromide + water

CdBr2

 

d.              lithium hydroxide + silicic acid, H4SiO4 à lithium silicate + water

Li4SiO4

 

e.               barium hydroxide + sulfurous acid à  barium sulfite + water

BaSO3

 

71.  Reduce the following complete equations to net ionic form.

       a.    6 Cr(NO3)2 + 3 CuSO4 à 3 Cu + 4 Cr(NO3)3 + Cr2(SO4)3

              Cu2+ (aq) à Cu (s)

b.              H2SO4 à H2O + SO3

2 H+ (aq) + SO42- (aq) à H2O (l) + SO3 (g)

c.               P4O10 + 6 H2O à 4 H3PO4

P4O10 (s) + 6 H2O (l) à 12 H+ (aq) + 4 PO43- (aq)

d.              4 CuCNS + 7 KIO3 + 14 HCl à 4 HCN + 4 CuSO4 + 7 ICl + 7 KCl + 5 H2O

4 CNS2-(aq) + 7 IO31-(aq) + 14 H+(aq) à 4 HCN(aq) + 4 SO42-(aq) + 7 I1-(aq) + 5 H2O(l)

 

35.  What is the hydronium ion concentration of a solution in which the hydroxide ion concentration is 2.77 x 10-10 M? What is the pH of the solution?

       [H3O+] = 3.61 x 10-5 M           pH = 4.44

 

36.  Determine the hydroxide ion concentration in a solution whose hydronium ion concentration is 4.49 x 10-9 M. What is the pH of this solution?

       [OH-] = 2.23 x 10-6 M                    pH = 8.35

 

37.  What is the pH of 0.0001 M NaOH?

       4

 

38.  What is the pH of freshly pressed apple juice, if the H3O+ concentration is 1.74 x 10-4 M?

       3.76

 

39.  What kinds of compounds function as indicators?

       Weak organic acids and bases that are colored

 

41.  What volume of 0.196 M LiOH is required to neutralize 25.0 cm3 of 0.413 M HBr?

LiOH + HBr à HOH + LiBr

       52.7 cm3 = 52.7 mL

 

46.  Find the hydroxide ion concentration of a solution with a pOH of 6.13.

       7.41 x 10-7 M

 

47.  Using Figure 24.6, calculate pOH for each of the following:

       a.    stomach contents

              12

 

b.              beer

9.5

 

c.               pumpkin pulp

9

 

d.              saliva

7

 

e.               eggs

6.2

 

f.                bile

7.1

48.  Calculate the [OH-] for lemon juice, pH = 2.3, and baking soda solution, pH = 8.5.

       Lemon juice = [OH-] = 2.0 x 10-12 M

       Baking soda = [OH-] = 3.2 x 10-6 M

 

57.  What is a titration? Why is a standard solution necessary for a titration?

       Lab technique that determines an unknown concentration using a known concentration

 

To find a concentration from another solution, you need to know the concentration to a high degree of accuracy. A standard provides that accuracy.