7. (16 point) (a) The pH of a 1.00 L buffer solution containing 0.15 M HOCl and 0.15 M NaOCl is 7.52.
HOCl (aq) + H20 (l) ---> OCl- (aq) + H3O+ (aq)
(a) Calculate the pH change when 0.40 g of NaOH is added to 1.00 L of a buffer solution containing 0.15 M HOCl and 0.15 M NaOCl. Neglect any volume change. Ka of HOCl is 3.0 x 10-8.


















(b) Calculate the pH change when 0.200 L of 0.100 M HCl is added to 1.00 L of a buffer solution containing 0.15 M HOCl and 0.15 M NaOCl. Assume the total volume of the solution is 1.20 L. Ka of HOCl is 3.0 x 10-8.

Nitrogen from gaseous phase is to be diffused into pure iron at 973 K. Surface is maintained at 0.1 wt% N, what will be the concentration 1 mm from the surface after 10 hours? diffusion coefficient at 700 C is 2.5E-11 m^2/s

Please show your work!

A) 0.46 wt%
B) 0.010 wt%
C) 0.1 wt%
D) 0.046 wt%

  12. In a solution, when the concentrations of a weak acid and its conjugate base are equal,….

[A] the system is not at equilibrium

[B] the -log of the [H⁺] and the -log of the K_a are equal

[C] the buffering capacity is significantly decreased

[D] the buffering capacity is significantly increased

[E] All of the above are true.

13. The concentration of iodide ions in a saturated solution of lead (II) iodide is ________ M.

The solubility product constant of PbI₂ is 1.4 x 10^-8.

[A] 1.4 x 10^-8 [B] 1.5 x 10^-3 [C] 3.5 x 10^-9 [D] 3.8 x 10^-4 [E] 3.0 x 10^-3

14. The solubility of lead (II) chloride (PbCl₂) is 1.6 x 10^-2 M. What is the K_sp of PbCl₂?

   [A] 4.1 x 10^-6 [B] 1.6 x 10^-5 [C] 3.1 x 10^-7 [D] 5.0 x 10^-4 [E] 1.6 x 10^-2

  15. The solubility of manganese (II) hydroxide (Mn(OH)₂) is 2.2 x 10^-5 M. What is the K_sp of

   Mn(OH)₂?

[A] 2.2 x 10^-5 [B] 2.1 x 10^-14 [C] 1.1 x 10^-14 [D] 4.8 x 10^-10 [E] 4.3 x 10^-14

16. Which of these expressions correctly expresses the solubility-product constant for

Ag₃PO₄ in water?

[A] [Ag][PO₄] [B] [Ag⁺][PO₄³⁻] [C] [Ag⁺]³[PO₄³⁻]

   [D] [Ag⁺][PO₄³⁻]³ [E] [Ag⁺]³[PO₄³⁻]³

  17. A solution of NaF is added dropwise to a solution that is 0.0166 M in Ba²⁺. When the

   concentration of F^- exceeds ________ M, BaF₂ will precipitate. Neglect volume changes.

For BaF₂, K_sp = 1.7 ⋅ 10^-6.

[A] 1.0 x 10^-2 [B] 1.0 x 10^-4 [C] 5.1 x 10^-5 [D] 2.5 x 10^-3 [E] 2.8 x 10^-8

18. A solution contains 2.3 x 10^-4 M Ag⁺ and NaI solution is being added drop wise. What

   is the minimum concentration of I^- to begin precipitation of AgI? Ksp (AgI)= 8.3 x 10^-17

   [A] 8.32 x10^-17 M [B] 2.51 x 10^-17 M [C] 3.01 x 10^-15

   [D] 3.51 x 10^-14 M [E] 3.61 x 10^-13 M

1e. The formula for the compound name iodic acid:

Group of answer choices

• HIO4
• HI
• HIO3
• HCO2

1f. The name of the compound Cl2O3:

Group of answer choices

• dichloride oxide
• dichloride trioxygen
• dichlorine trioxide
• dichlorine trioxygen
• chloroxide

1g. The total number of valence electrons for molecule H2S:

Group of answer choices

• 6
• 2
• 16
• 8
• 18

1h. The molecular geometry of H2S:

Group of answer choices

• pyramidal
• bent
• linear
• triagonal planar

1i. The polarity of molecule H2S:

Group of answer choices

• nonpolar
• polar
• can't be determined
• ionic

1j. Which acid would dissociate partially in water to produce hydrogen ions?

Group of answer choices

• HBr
• HI
• H3PO4
• H2SO4

Consider the following reactions:

Zn^2+ + 4H3 <----> Zn(NH3)4^2+ beta 4 = 5.01 x 10^8

Zn^2+ + 2e^- <-----> Zn(s) E degree = -0.762 V

Assuming there is negligible current and nearly all Zn^2+ is in the form Zn(NH3)4^2+. what cathode potential (vs. S.H.E.) would be required to reduce 99.99% of the Zn^2+ from a solution containing 0.20 M Zn^2+ in 1.4 M ammonia? (Assume T= 298 K)

________V

1. What is the concentration of hydroxide ions [OH- ] in pure water?

2. For each type of acid and base below first define acid and evaluate Fe⁺³ as an acid by each definition. a: Arrhenius b: Bronsted Lowry c: Lewis

3. For each salt below identify if it will form a slightly acidic or basic solution, support your answers with a chemical equation as evidence. a. Na(SO₃)₂ b. NH₄Br.

10. Given the data below, what is ∆Hr for the reaction:

FeO   + CO → CO₂   +   Fe

                                                                                  ∆H_r

Fe₂O₃ + 3CO → 2Fe + 3CO₂                   –35kJ

3Fe₂O₃   + CO → CO₂ + 2Fe₂O₄              –70 kJ

Fe₃O₄ + CO → 3FeO   + CO₂                    +45 kJ

A solution of pentane and ethanol CH3CH2OH that is 50.% pentane by mass is boiling at 57.2°C. The vapor is collected and cooled until it condenses to form a new solution.

Calculate the percent by mass of pentane in the new solution. Here's some data you may need:

Be sure your answer has the correct number of significant digits.

Note for advanced students: you may assume the solution and vapor above it are ideal.

An equilibrium mixture contains 0.6500.650 mol of each of the products (carbon dioxide and hydrogen gas) and 0.2000.200 mol of each of the reactants (carbon monoxide and water vapor) in a 1.00 L container.

CO(g)+H2O(g)−⇀↽−CO2(g)+H2(g)CO(g)+H2O(g)↽−−⇀CO2(g)+H2(g)

How many moles of carbon dioxide would have to be added at constant temperature and volume to increase the amount of carbon monoxide to 0.3000.300 mol once equilibrium has been reestablished?

CH 15

± Using the Equilibrium Constant

1)

Part A

Initially, only A and B are present, each at 2.00 M. What is the final concentration of A once equilibrium is reached?

Part B

What is the final concentration of D at equilibrium if the initial concentrations are [A] = 1.00 M and [B] = 2.00 M ?

2)

Part A

A mixture initially contains A, B, and C in the following concentrations: [A] = 0.700 M , [B] = 1.20 M , and [C] = 0.600 M . The following reaction occurs and equilibrium is established:

A+2B⇌C

At equilibrium, [A] = 0.600 M and [C] = 0.700 M . Calculate the value of the equilibrium constant, Kc.

Express your answer numerically.

Part A

If Kb for NX3 is 4.0×10⁻⁶, what is the pOH of a 0.175 M aqueous solution of NX3?

Part B

If Kb for NX3 is 4.0×10⁻⁶, what is the percent ionization of a 0.325 M aqueous solution of NX3?

Express your answer numerically to three significant figures.

Part C

If Kb for NX3 is 4.0×10⁻⁶ , what is the the pKa for the following reaction?

HNX3+(aq)+H2O(l)⇌NX3(aq)+H3O+(aq)

Express your answer numerically to two decimal places.

Write the net ionic equation, including phases, for the dissolution of CaF₂(s) in H₃O⁺(aq).
Make sure your reaction is balanced, and do not include any spaces.

b. Briefly explain the differences between a boundary surface and the radial distribution function for hydrogenic atoms.

A solution contains 43.0 g of heptane (C7H16) and 46.0 g of octane (C8H18) at 25 ∘C. The vapor pressures of pure heptane and pure octane at 25 ∘C are 45.8 torr and 10.9 torr, respectively. Assuming ideal behavior, calculate each of the following.

The vapor pressure of heptane in the mixture.
The vapor pressure of octane in the mixture.
The total pressure above the solution.
What is the concentration of heptane in mass percent?
What is the concentration of octane in mass percent?

Why is the composition of the vapor different from the composition of the solution?