Question 1

Calculate the ionic strength of a 0.210 M FeCl2 solution.

Accepted Answer

0.630

Question 2

All of the following are TRUE for activities and activity coefficients,except:

Accepted Answer

A) activity for a chemical species is the product of concentration and activity coefficient. 
B) the activity coefficient corrects for non-ideal behavior due to ionic strength. 
C) as ionic strength increases,the value of the activity coefficient increases. 
D) for ions,the activity coefficient approaches unity as the ionic strength approaches 0. 
E) the activity coefficient for neutral molecules is approximately unity when the ionic strength is less than 0.1 M. 
A) activity for a chemical species is the product of concentration and activity coefficient. 
B) the activity coefficient corrects for non-ideal behavior due to ionic strength. 
C) as ionic strength increases,the value of the activity coefficient increases. 
D) for ions,the activity coefficient approaches unity as the ionic strength approaches 0. 
E) the activity coefficient for neutral molecules is approximately unity when the ionic strength is less than 0.1 M. C

Question 3

Calculate the pH of a 0.040 M HCl solution that is also 0.010 M in NaNO3.

Accepted Answer

pH = 1.46
This problem requires Table 8.1 for the students to look up the activity coefficients for H⁺ and Cl⁻._H+ = 0.86,_Cl₋ = _NO₃₋ = 0.805 and _Na+ = 0.82 when  = 0.05 M.
Since HCl is a strong base,the hydronium concentration is 0.04.Calculate the pH using the activity coefficient for H⁺.
8-5 Applying the Systematic Treatment of Equilibrium

Question 4

Which statement below is NOT correct for the pH of a 0.01 M NaCl solution versus the pH of a 0.01 M in FeSO4 solution?

Accepted Answer

A) The activity coefficient for H+ will be larger in 0.01 M NaCl than in 0.01 M FeSO4. 
B) The activity coefficient for OH− will be larger in 0.01 M NaCl than in 0.01 M FeSO4. 
C) The hydronium concentration in 0.01 M NaCl will equal the hydronium concentration in 0.01 M FeSO4. 
D) The H+ activity in 0.01 M NaCl will not equal the H+ activity in 0.01 M FeSO4. 
E) The OH− activity in 0.01 M NaCl will not equal the OH− activity in 0.01 M FeSO4. 
A) The activity coefficient for H+ will be larger in 0.01 M NaCl than in 0.01 M FeSO4. 
B) The activity coefficient for OH− will be larger in 0.01 M NaCl than in 0.01 M FeSO4. 
C) The hydronium concentration in 0.01 M NaCl will equal the hydronium concentration in 0.01 M FeSO4. 
D) The H+ activity in 0.01 M NaCl will not equal the H+ activity in 0.01 M FeSO4. 
E) The OH− activity in 0.01 M NaCl will not equal the OH− activity in 0.01 M FeSO4.

Question 5

Calculate the pH of a 0.010 M CH3CO2H solution.Ka = 1.8 × 10−5 for acetic acid.

Accepted Answer

A) 9)26 
B) 3)39 
C) 2)02 
D) 10.61 
E) 4)74 
A) 9)26 
B) 3)39 
C) 2)02 
D) 10.61 
E) 4)74

Question 6

The mass balance equation for a 0.10 M HO2CCO2H solution is which of the following?

Accepted Answer

A)   
B)   
C)   
D)   
E)   
A)   
B)   
C)   
D)   
E)

Question 7

Which statement below is INCORRECT for the increased solubility of a sparingly soluble salt,AgCl,in an inert salt solution,NaNO3?

Accepted Answer

A) The ionic atmosphere around the silver cations becomes increasingly negative as the nitrate anions are attracted to the silver cations. 
B) The ionic strength around the chloride anions becomes increasingly positive as the sodium cations are attracted to the chloride anions. 
C) The ionic atmosphere increases the attraction between silver cations and chloride anions,increasing solubility by creating more AgCl (aq)in solution. 
D) Ions continually diffuse into and out of the ionic atmosphere. 
E) The negative ionic atmosphere around silver cations results in an overall positive charge less than the positive charge of the silver cations. 
A) The ionic atmosphere around the silver cations becomes increasingly negative as the nitrate anions are attracted to the silver cations. 
B) The ionic strength around the chloride anions becomes increasingly positive as the sodium cations are attracted to the chloride anions. 
C) The ionic atmosphere increases the attraction between silver cations and chloride anions,increasing solubility by creating more AgCl (aq)in solution. 
D) Ions continually diffuse into and out of the ionic atmosphere. 
E) The negative ionic atmosphere around silver cations results in an overall positive charge less than the positive charge of the silver cations.

Question 8

Calculate the activity coefficient for Fe2+ for an ionic strength of 0.034 M.For F1F1F1S1F1F1F10 = 0.01 M,F1F1F1S1F1F1F10 = 0.675 and for F1F1F1S1F1F1F10 = 0.05 M,F1F1F1S1F1F1F10 = 0.485.

Accepted Answer

F1F1F1S1F1F1F10 = 0

Question 9

What is the ionic strength of a 2:1 electrolyte with a concentration of 0.100 M?

Accepted Answer

A) 0)100 
B) 0)200 
C) 0)300 
D) 0)400 
E) 0)500 
A) 0)100 
B) 0)200 
C) 0)300 
D) 0)400 
E) 0)500

Question 10

____________________ is a measure of the total concentration of ions in solution.

Accepted Answer

A) Ionic radius 
B) Ionic density 
C) Ionic degree 
D) Ionic strength 
E) Ionic atmosphere 
A) Ionic radius 
B) Ionic density 
C) Ionic degree 
D) Ionic strength 
E) Ionic atmosphere

Question 11

Which of the following is NOT true for pH?

Accepted Answer

A) pH = −log[H+]F1F1F1S1F1F1F10H+. 
B) pH = −log[H+] when F1F1F1S1F1F1F10 = 0. 
C) The pH = pOH for pure water. 
D) As ionic strength increases,so does the pH of pure water. 
E) The ionic strength of pure water is 1.0 x 10−7 M. 
A) pH = −log[H+]F1F1F1S1F1F1F10H+. 
B) pH = −log[H+] when F1F1F1S1F1F1F10 = 0. 
C) The pH = pOH for pure water. 
D) As ionic strength increases,so does the pH of pure water. 
E) The ionic strength of pure water is 1.0 x 10−7 M.

Question 12

Calculate the pOH of a 0.010 M HCl solution with an ionic strength of 0.10 M.F1F1F1S1F1F1F10H+ = 0.83,F1F1F1S1F1F1F10OH− = 0.76.

Accepted Answer

A) 11.92 
B) 11.80 
C) 11.88 
D) 12.00 
E) 12.20 
A) 11.92 
B) 11.80 
C) 11.88 
D) 12.00 
E) 12.20

Question 13

A buffer is prepared from NaH2PO4 and Na2HPO4.The charge balance equation for the buffer is which of the following?

Accepted Answer

A)   
B)   
C)   
D)   
E)   
A)   
B)   
C)   
D)   
E)

Question 14

For Ag+ when F1F1F1S1F1F1F10 = 0.01 M,F1F1F1S1F1F1F10 = 0.898 and when F1F1F1S1F1F1F10 = 0.05,F1F1F1S1F1F1F10 = 0.80.What is the activity coefficient when F1F1F1S1F1F1F10 = 0.024 M?

Accepted Answer

A) 0)804 
B) 0)845 
C) 0)853 
D) 0)864 
E) 0)894 
A) 0)804 
B) 0)845 
C) 0)853 
D) 0)864 
E) 0)894

Question 15

Which of the statements below are INCORRECT for mass balance and charge balance?
I The mass balance is a statement of the conservation of matter.
II Mass balance is satisfied when the quantity of all species in a solution containing a particular atom (or group of atoms)equals the amount of that atom (or group)reacted.
III The sum of the positive charges in solution equals the sum of the negative charges in solution.
IV The coefficient in front of each species in a charge balance always equals the magnitude of the charge on the counter ion.

Accepted Answer

A) I,II,III and IV 
B) I,III and IV 
C) I,II and III 
D) I and IV 
E) II and III 
A) I,II,III and IV 
B) I,III and IV 
C) I,II and III 
D) I and IV 
E) II and III

Question 16

Calculate the pH of a 0.002 M (CH3)3N solution.Kb = 6.6 × 10−5

Accepted Answer

Question 17

To correct for the effect of ionic strength on chemical reactions,concentrations are replaced by____________________ in equilibrium expressions.

Accepted Answer

A) activity coefficients 
B) ion activities 
C) molecular activities 
D) activities 
E) active strength 
A) activity coefficients 
B) ion activities 
C) molecular activities 
D) activities 
E) active strength

Question 18

Calculate the pH of a 0.001 M HCN solution.Ka = 6.2 × 10−10

Accepted Answer

Question 19

Which equation is NOT required to determine the molar solubility of AgCN?

Accepted Answer

A) AgCN ⇋ Ag+ + CN−____________________Ksp = 2.2 × 10−16 
B) H2O + H2O ⇋ H3O+ + OH− Kw = 1 × 10−14 
C) [Ag+] = [CN−] + [HCN] 
D) CN− + H2O ⇋ HCN + OH− Kb = 1.6 × 10−5 
E) HCN + H2O ⇋ CN− + H3O+ Ka = 6.2 × 10−10 
A) AgCN ⇋ Ag+ + CN−____________________Ksp = 2.2 × 10−16 
B) H2O + H2O ⇋ H3O+ + OH− Kw = 1 × 10−14 
C) [Ag+] = [CN−] + [HCN] 
D) CN− + H2O ⇋ HCN + OH− Kb = 1.6 × 10−5 
E) HCN + H2O ⇋ CN− + H3O+ Ka = 6.2 × 10−10

Question 20

Which equation is NOT required to determine the pH of 0.10 M solution of weak acid,HA?

Accepted Answer

A) HA + H2O ⇋ A− + H3O+ Ka = 2.4 × 10−6 
B) H2O + H2O ⇋ H3O+ + OH− Kw = 1 × 10−14 
C) 0)10 = [HA] + [A−] 
D) [H3O+] = [OH−] + [A−] 
E) A− + H2O ⇋ HA + OH− Kb = 4.2 × 10−9 
A) HA + H2O ⇋ A− + H3O+ Ka = 2.4 × 10−6 
B) H2O + H2O ⇋ H3O+ + OH− Kw = 1 × 10−14 
C) 0)10 = [HA] + [A−] 
D) [H3O+] = [OH−] + [A−] 
E) A− + H2O ⇋ HA + OH− Kb = 4.2 × 10−9

Exam 9: Activity and the Systematic Treatment of Equilibrium

Calculate the ionic strength of a 0.210 M FeCl2 solution.

All of the following are TRUE for activities and activity coefficients,except:

Calculate the pH of a 0.040 M HCl solution that is also 0.010 M in NaNO3.

Which statement below is NOT correct for the pH of a 0.01 M NaCl solution versus the pH of a 0.01 M in FeSO4 solution?

Calculate the pH of a 0.010 M CH3CO2H solution.Ka = 1.8 × 10−5 for acetic acid.

The mass balance equation for a 0.10 M HO2CCO2H solution is which of the following?

Which statement below is INCORRECT for the increased solubility of a sparingly soluble salt,AgCl,in an inert salt solution,NaNO3?

Calculate the activity coefficient for Fe2+ for an ionic strength of 0.034 M.For  = 0.01 M, = 0.675 and for  = 0.05 M, = 0.485.

What is the ionic strength of a 2:1 electrolyte with a concentration of 0.100 M?

____________________ is a measure of the total concentration of ions in solution.

Which of the following is NOT true for pH?

Calculate the pOH of a 0.010 M HCl solution with an ionic strength of 0.10 M.H+ = 0.83,OH− = 0.76.

A buffer is prepared from NaH2PO4 and Na2HPO4.The charge balance equation for the buffer is which of the following?

For Ag+ when  = 0.01 M, = 0.898 and when  = 0.05, = 0.80.What is the activity coefficient when  = 0.024 M?

Calculate the pH of a 0.002 M (CH3)3N solution.Kb = 6.6 × 10−5

To correct for the effect of ionic strength on chemical reactions,concentrations are replaced by____________________ in equilibrium expressions.

Calculate the pH of a 0.001 M HCN solution.Ka = 6.2 × 10−10

Which equation is NOT required to determine the molar solubility of AgCN?

Which equation is NOT required to determine the pH of 0.10 M solution of weak acid,HA?

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Filters

Calculate the ionic strength of a 0.210 M FeCl₂ solution.

Calculate the pH of a 0.040 M HCl solution that is also 0.010 M in NaNO₃.

Which statement below is NOT correct for the pH of a 0.01 M NaCl solution versus the pH of a 0.01 M in FeSO₄ solution?

Calculate the pH of a 0.010 M CH₃CO₂H solution.K_a = 1.8 × 10−⁵ for acetic acid.

The mass balance equation for a 0.10 M HO₂CCO₂H solution is which of the following?

Which statement below is INCORRECT for the increased solubility of a sparingly soluble salt,AgCl,in an inert salt solution,NaNO₃?

Calculate the activity coefficient for Fe²⁺ for an ionic strength of 0.034 M.For  = 0.01 M, = 0.675 and for  = 0.05 M, = 0.485.

Calculate the pOH of a 0.010 M HCl solution with an ionic strength of 0.10 M._H+ = 0.83,_OH₋ = 0.76.

A buffer is prepared from NaH₂PO₄ and Na₂HPO₄.The charge balance equation for the buffer is which of the following?

For Ag⁺ when  = 0.01 M, = 0.898 and when  = 0.05, = 0.80.What is the activity coefficient when  = 0.024 M?

Calculate the pH of a 0.002 M (CH₃)₃N solution.K_b = 6.6 × 10⁻⁵

Calculate the pH of a 0.001 M HCN solution.K_a = 6.2 × 10⁻¹⁰