Chapter 7 3 Based on the positions in the periodic table of elements

Assume that the conductivity of a solution depends only on the total concentration of dissolved

ions and that you measure the conductivity of three different solutions while performing

titrations in which:

I. 50.00 mL of 0.100 M aqueous CH3CO2H is titrated by addition of 0.100 M NaOH.

II. 50.00 mL of 0.100 M aqueous NaBr is titrated by addition of 0.100 M AgNO3.

III. 50.00 mL of 0.100 M aqueous CaCl2 is titrated by addition of 0.100 M Na2CO3.

113) Which of the above graphs corresponds to titration I?

A) graph (1)

B) graph (2)

C) graph (3)

D) none of the graphs

114) Which of the above graphs corresponds to titration II?

A) graph (1)

B) graph (2)

C) graph (3)

D) none of the graphs

115) Which of the above graphs corresponds to titration III?

A) graph (1)

B) graph (2)

C) graph (3)

D) none of the graphs

116) Based on the positions in the periodic table of elements A, B, and C, which of the following

reactions would you expect to occur?

A) A2+ + B → A + B2+

B) B2+ + C → B + C2+

C) C + A → C2- + A2+

D) None of the reactions would be expected to occur.

117) Based on the positions in the periodic table of elements A, B, and C, which of the following

reactions would you expect to occur?

A) A2+ + B → A + B2+

B) B2+ + C → B + C2+

C) C2+ + A → C + A2+

D) None of the reactions would be expected to occur.

7.2 Algorithmic Questions

1) H Cl , HI , H2SO4, Li Cl , and KI are all classified as

A) acids.

B) nonelectrolytes.

C) strong electrolytes.

D) weak electrolytes.

2) What is the molar concentration of sodium ions in a 0.450 M Na3PO4 solution?

A) 0.150 M

B) 0.450 M

C) 1.35 M

D) 1.80 M

3) Which one of the following compounds is insoluble in water?

A) Ca Cl2

B) NaNO3

C) Pb Cl2

D) K2CO3

4) Which one of the following compounds is soluble in water?

A) Cu3(PO4)2

B) CoS

C) Pb(NO3)2

D) ZnCO3

5) Which pair of compounds is soluble in water?

A) Ag Cl and AgBr

B) CoS and K2S

C) NaI and Cu(NO3)2

D) NH4NO3 and BaCO3

6) The mixing of which pair of reactants will result in a precipitation reaction?

A) CsI(aq) + NaOH(aq)

B) HCl(aq) + Ca(OH)2(aq)

C) K2SO4(aq) + Hg2(NO3)2(aq)

D) NaNO3(aq) + NH4Cl(aq)

7) The mixing of which pair of reactants will result in a precipitation reaction?

A) Ba(NO3)2(aq) + Na2CO3(aq)

B) K2SO4(aq) + Cu(NO3)2(aq)

C) NaClO4(aq) + (NH4)2S(aq)

D) NH4Br(aq) + NH4I(aq)

8) What reagent could be used to separate Br– from CH3CO2– when added to an aqueous

solution containing both?

A) AgNO3 (aq)

B) Ba(OH)2 (aq)

C) CuSO4 (aq)

D) NaI (aq)

9) What reagent could not be used to separate Br– from CO32- when added to an aqueous

solution containing both?

A) AgNO3 (aq)

B) Ca(NO3)2 (aq)

C) Cu(NO3)2 (aq)

D) Fe(NO3)2(aq)

10) Which of the following compounds is not an Arrhenius acid?

A) CH3CO2H

B) CH3CH2NH2

C) HNO2

D) H2SO4

11) Which of the following compounds is an Arrhenius base in water?

A) C6H12O6

B) HOCl

C) H2SO4

D) C6H5NH2

12) Which of the following compounds is an Arrhenius base?

A) CH3OH

B) CH3CO2H

C) HOCl

D) CsOH

13) Which one of the following compounds behaves as an acid when dissolved in water?

A) RaO

B) C4H10

C) HI

D) RbOH

14) Which of the compounds of H2C2O4, Ca(OH)2, KOH, and HI, behave as acids when they

are dissolved in water?

A) Ca(OH)2 and KOH

B) O4 and HI

C) only HI

D) only KOH

15) Which of the compounds H2C2O4, Ca(OH)2, KOH, and HI, behave as bases when they are

dissolved in water?

A) Ca(OH)2 and KOH

B) H2C2O4 and HI

C) only HI

D) only KOH

16) When dissolved in water, KOH behaves as

A) an acid that forms K+ and OH– ions.

B) an acid that forms KO– and H+ ions.

C) a base that forms K+ and OH– ions.

D) a base that forms KO– and H+ ions.

17) An aqueous solution of H2S is named

A) hydrosulfuric acid.

B) hydrosulfurous acid.

C) sulfuric acid.

D) sulfurous acid.

18) The chemical formula for nitrous acid is

A) H3N(aq).

B) H NO2(aq).

C) H NO3(aq).

D) H2N2O6(aq).

19) What is the oxidation number of the sulfur atom in K2SO4 ?

A) -2

B) +2

C) +4

D) +6

20) What is the oxidation number of the chromium atom in K2Cr2O4 ?

A) -2

B) +2

C) +6

D) +7

21) What is the oxidation number of the oxygen atom in Na2O2 ?

A) -2

B) -1

C) +1

D) +2

22) How many electrons are needed for bromine in the balanced oxidation half-reaction?

Br O3– (aq) + H+(aq) → Br–(aq) + H2O(l)?

A) -7

B) -6

C) +6

D) +7

23) Using the following portion of the activity series for oxidation half reactions, determine

which combination of reactants will result in a reaction.

Na(s) → Na +(aq) + e–

Cr(s) → Cr3+(aq) + 3 e–

A) Na(s) with Cr(s)

B) Na(s) with Cr3+(aq)

C) Na +(aq) with Cr3+(aq)

D) Na +(aq) with Cr(s)

24) What are the coefficients in front of NO3–(aq) and Cu(s) when the following redox equation

is balanced in an acidic solution:

___ NO3–(aq) + ___ Cu(s) → ___ NO(g) + ___ Cu2+(aq)?

A) 2, 3

B) 2, 6

C) 3, 4

D) 3, 6

25) According to the balanced equation shown below, 4.00 mole of oxalic acid, H2C2O4, reacts

with ________ moles of permanganate, MnO4–.

5 H2C2O4(aq) + 2 MnO4–(aq) + 6 H+(aq) → 10 CO2(g) + Mn2+(aq) + 8 H2O(l)

A) 1.60

B) 4.00

C) 8.00

D) 9.00

26) Based on the balanced chemical equation shown below, what volume of 0.250 M

K2S2O3(aq), is needed to completely react with 24.88 mL of 0.125 M KI3(aq), according to the

chemical equation:

2 S2O32-(aq) + I3–(aq) → S4O62-(aq) + 3 I–(aq).

A) 6.22 mL

B) 12.4 mL

C) 24.9 mL

D) 99.5 mL

27) What is the molarity of a potassium triiodide solution, KI3(aq), if 30.00 mL of the solution is

required to completely react with 25.00 mL of a 0.200 M thiosulfate solution, K2S2O3(aq)? The

chemical equation for the reaction is

2 S2O32-(aq) + I3–(aq) → S4O62-(aq) + 3 I–(aq).

A) 0.0833 M

B) 0.120 M

C) 0.167 M

D) 0.333 M

28) Based on the balanced chemical equation shown below, determine the molarity of a solution

containing Fe2+(aq), if 40.00 mL of the Fe2+(aq) solution is required to completely react with

30.00 mL of a 0.250 M potassium bromate, KBrO3(aq), solution. The chemical equation for the

reaction is

6 Fe2+(aq) + BrO3–(aq) + 6 H+(aq) → 6 Fe3+(aq) + Br–(aq) + 3 H2O(l).

A) 0.0312 M

B) 0.188 M

C) 1.12 M

D) 2.00 M

29) Based on the balanced chemical equation shown below, determine the mass percent of Fe3+

in a sample of iron ore, if 22.40 mL of a 0.1000 M stannous chloride, SnCl2(aq),

solution is required to completely react with the Fe3+ present in the ore sample. The chemical

equation for the reaction is

2 Fe3+(aq) + Sn2+(aq) → 2 Fe2+(aq) + Sn4+(aq).

A) 5.365%

B) 8.396%

C) 16.79%

D) 33.58%

7.3 Short Answer Questions

1) What are the two products of the reaction H3PO4(aq) + 3 KOH(aq) → ?

2) CH3CO2H is an example of a ________ electrolyte.

43

3) The balanced net ionic equation for the reaction Na2SO4(aq) + Pb(NO3)2(aq) → PbSO4(s) +

2 NaNO3(aq) is ________.

4) The compound K2S is predicted to be soluble based on the solubility guideline that all

________ are soluble.

5) Because it forms some H+ and OCl– ions when dissolved in water, the molecule HOCl is

classified as a(n) ________.

6) In the reaction CH3CO2H(aq) + Ca(OH)2(aq) → Ca(CH3CO2)2(aq) + 2 H2O(l)the acid is

________ and the base is ________.

7) The oxidation number of chromium in Na2Cr2O7 is ________.

8) In the reaction 2 MnO4–(aq) + 10 Br–(aq) + 16 H+(aq) → 2 Mn2+(aq) +5 Br2(aq) + 8

H2O(aq) the reducing agent is ________.

9) The reaction Cu(s) + 2 HCl(aq) → CuCl2(aq) + H2(g) is predicted not to occur because Cu is

________ than H+ in the activity series.

44

10) When the equation MnO4–(aq) + C2O42–(aq) →Mn2+(aq) + CO2(g) is balanced using the

smallest whole numbers, the coefficient in front of the CO2(g) is ________.

11) In the redox reaction 2 S2O32–(aq) + I3–(aq) → S4O62–(aq) + 3 I–(aq), if 18.75 mL of

0.2500 M Na2S2O3 is needed for complete reaction with 15.00 mL of the I3– solution, what is

the molar concentration of I3–?