10. What is the [CH3COOH ]/[CH3COO– ] ratio in an acetic acid/sodium acetate buffer at pH = 4.90? (Ka = 1.8 x 10–5 )

a. 0.31

b. 0.70

c. 1.45

d. 2.41

e. 4.90

11. How many grams of NaCH3COO should be added to 250 mL of 0,100 M CH3COOH when the above solution is prepared?

a. 0.431 g

b. 2.95 g

c. 5.66 g

d. 1.43 g

e.11.9 g

Compare and contrast all 4 types of distillation

What change in pH should be observed if 10.0 mL of 0.100 M NaOH is added to 100 mL of a buffer that is 0.100 M in CH₃COOH and 0.100 M in NaCH₃CO₂? K_a for acetic acid is 1.8 x 10^-5.

If you can explain step by step that would be awesome!

Sodium hypochlorite (NaClO) is the active ingredient in household bleach. HClO has a Ka of 4.0 x 10^-8 . You are titrating 30.0 mL of 0.10 M NaClO solution using 0.30 M HCl solution.

1) What is the pK_a of HClO and the K_b of ClO- ?

2)What volume of the HCl solution (in mL) needs to be added to reach the equivalence point in this titration experiment? Show your work.

3)What volume of the HCl solution (in mL) needs to be added to adjust the pH of the starting solution to 7.40?

4) At the equivalence point, would you predict the pH to be acidic, basic, or neutral? What is the exact pH of this solution at the equivalence point? Express your answer to two decimal places. Show your work

Consider the reaction that you did to deprotonate vanillin using sodium hydroxide. If the pKa of vanillin is about 7.4, what is the equilibrium constant for the reaction of vanillin with sodium hydroxide to make the conjugate base of vanillin?

Write out the balanced equation, add arrows to show the mechanism of the reaction, and show your work/calculation(s).

Conformational analysis of a molecule was performed using a global-optimisation method where the energy was evaluated using Hartree-Fock (HF) theory. The binding energy of the low-energy conformers with a host complex was then calculated using the same level of theory. It was found that the lowest-energy conformer matched well with a known X-ray crystal structure but the binding energy with the host molecule was far too small.

(i) Define the term conformer.

(ii) Explain the general principles of global optimisation of a molecule and why global optimisation is challenging to perform.

(iii) Summarise the main contributions and terms that Hartree-Fock theory captures.

(iv)Explain why the low-energy conformers might be reasonably modelled by HF theory.

The energies of the ? MOs obtained from Hückel MO theory for ? sp2 hybridised carbon atoms forming a linear chain are given by:

?? = ? + 2?cos ( ?? ? + 1 )

where ? is the energy level (? = 1,2, … , ?) in order of increasing energy.

(i) Give the values of ? for the HOMO and LUMO in butadiene.

(ii) The energy required to promote an electron from the HOMO to the LUMO of butadiene was measured to be 309 kJ/mol. Determine the value of ?

2Cu²⁺ + 4KI → 2CuI + I₂ + 4K⁺ (rxn 1)

I₂ + 2Na₂S₂O₃ → 2NaI + Na₂S₄O₆ (rxn 2)

10.0 mL of a Cu²⁺ solution of unknown concentration was placed in a 250 mL Erlenmeyer flask. An excess of KI solution was added. Indicator was added and the solution was diluted with H₂O to a total volume of 75 mL. The solution was titrated with 0.20 M Na₂S₂O₃. The equivalence point of the titration was reached when 14.45 mL of Na₂S₂O₃ had been added. What is the molar concentration of Cu²⁺ in the unknown solution?

How do you determine if an element or compund is electron rich? please provide examples.

If I have 2.5mL of KCl and 3 mL of water.

Which one is my solvent? _____________________________

Which one is my solute? ______________________________

Lab: Hydrolysis of polyethylene terephthalate using KOH

1. Why do we need to keep this reaction well stirred?

2. what is the scope of this reaction?

3. IR and NMR interpretation of dimethyl terephthalate

4. What is the role of 1-pentanol and water in this experiment?

5. Explain Alkaline hydrolysis of PET using KOH (in words).