1. Calculate the grams of NaCH₃COO required for 150.0 mL of 0.20 M CH₃COOH solution to achieve a pH of 4.40. (Assume no volume change.)  (K_a = 1.8 x 10^-5 )

2. What is the pH of 100.0 mL of buffer consisting of 0.20 M CH₃COOH/0.20 M NaCH₃COOafter 15.0 mL of 0.25 M HCl was added into the solution? (K_a = 1.8 x 10^-5)

3. Are the following solutions reasonable buffers? Please provide an explanation for each answer.

1. 1.0 M H₃PO₄ and 1.0 M NaH₂PO₃
2. 1.0 M H₂SO₄ and 1.0 M HCl
3. 1.0 M NaOH and 0.50 M HCl

An experimental protocol calls for 25.4 mL of a solution in which the potassium ion concentration is 0.0872 M. How would you prepare this solution from pure solid potassium phosphate? (The solvent is water.)

(Please don’t forget to state how you would prepare the solution; don’t simply calculate the grams of potassium phosphate required.)

A chemical equation (even a balanced chemical equation) is not able to tell us how the reaction actually occurs. However, we can predict the rate law of a reaction, if we propose a plausible reaction mechanism. Consider the mechanism proposed for the decomposition reaction A 2 B + C, and understand the rate law from the molecular view.

(a) Derive the possible rate law based on mechanism (I). step 1: A k1 B + X slow step 2: X k2 B + C fast

(b) Derive the possible rate law based on mechanism (II). step 1: A k1 k−1 C + M fast step 2: M k2 2 B slow

(c) Comparing to the rate law in Question 1 (or Question 2), which mechanism is plausible for the decomposition reaction, (I) or (II) ?

For the reaction below, Kp = 29.21 at 800K. Calculate the equilibrium partial pressures of the reactants and products if the initial pressures are Ppcl5 = 0.488atm & Ppcl3 = .4900atm.

PCL5(g) <----> PCL3(g) + Cl2(g)

PCL5: ______ atm

Cl2: _______ atm

PCl3: ______ atm

List the different electron donating compounds that provide energy for the work done by biological organisms?

Question 12.12. The condensation of diatomic bromine (Br2) from a gaseous to a liquid state releases 7.4 kcal/mol. What is the sign of delta H for this process?
Positive
Negative

Where it occurs, write the hydrolysis of the anion/or cation.

1) NH4I

2) CH3COOLi

3) CsCIO4

An unknown Fe(II) sample is added to 2.50 mL of a 0.0300 M potassium dichromate solution (in acidic medium) in a 25 mL volumetric flask. 2 M H2SO4 is added to fill the flask to the calibration mark. After the reaction proceeds to completion, the absorbance of the solution at 447 nm is measured to be 0.550 using a 1.00-cm path length. Calculate the following and enter your answers with correct significant figures. Extinction coefficient of Cr2O72-in 2M sulfuric acid at 447 nm is 350. M-1cm-1

Molarity of Cr2O7 2- in the solution after reaction.

Moles of Cr2O7 2− that reacted.

Moles of Fe(II) that reacted.

Document all aspects of the 1D PIAB. Show the first five energy levels. Try your best to draw to scale. Include the wavefunctions, energy levels,and the impact of the uncertainty principle on the allowed integer values.What is the difference in the HOMO and 1stLUMO transition if you place nine (9)electrons into the box?

For each of the following write the correct chemical formula, predict the products, write the molecular, total ionic equation, and net ionic equations. Include states of matter in equations.

Sulfuric acid + barium chloride

Silver nitrate + ammonium bromide

Sodium hydroxide + Aluminum sulfate

Sodium carbonate + hydroiodic acid

A proposed mechanism for the preparation of COBr₂ from CO(g) and Br₂ is:

Br₂ ⇄ 2 Br (g) fast

Br(g) + CO (g) ⇄ COBr fast

COBr + Br₂ → COBr₂ + Br slow

The correct rate law for this mechanism is:

• A.

  k [CO][Br₂]

• B.

  k [CO] / [Br₂]^1/2

• C.

  k[Br₂]

• D.

  k [CO]²[Br₂]

• E.

  k [CO][Br₂]^3/2

Select the statements below that are false and think about why they are not true. a) If a chemical reaction is spontaneous then the ?Ssys must always be positive. b)If a chemical reaction with a negative ?Ssys is spontaneous then ?Ssurr must be positive. c) If a chemical reaction is spontaneous then the ?Euniv must be increasing. d) We don\'t need to worry about spontaneous reactions because they are rare.

If 2.46 g of Ar are added to 2.75 atm of He in a 2.00 L cylinder at 27.0

How many liters of 0.983 M LiOH will be needed to raise the pH of 0.129 L of 5.75 M sulfurous acid (H₂SO₃) to a pH of 6.653?

2) Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: 4Al (s) + 3O2 (g) → 2Al2O3 (s) In a particular experiment, 5.0 g of Al reacts with 4.0 g of O2.

a) What is the limiting reactant in this reaction?

b) What is the theorectical yield of Al2O3?

c) How much of the excess reactant is left?