A. One beaker contains 10.0 mL of acetic acid/sodium acetate buffer at maximum buffer capacity (equal concentrations of acetic acid and sodium acetate), and another contains 10.0 mL of pure water. Calculate the hydronium ion concentration and the pH after the addition of 0.25 mL of

0.10 M HCl to each one. What accounts for the difference in the hydronium ion concentrations? Explain this based on equilibrium concepts; in other words, saying that “one solution is a buffer” is not sufficient.

Ka of acetic acid = 1.8 x 10^-5

Acetic acid/sodium acetate buffer

Acetic acid .1M

Sodium acetate .1M

Your acid has a pka of 7.54 and a concentration of 0.084M. You are given 38.6mL of this acid, what is the pH of this initial solution? Calculate the pH of the solution after adding 8.7, 17.1, 30.5, and 33.3 mL of 0.100M NaOH. At the equivalence point, what volume of base is added and what is the pH?

-Give the reaction of the dissolution of NH4Cl in water (Use lowest possible coefficients. Include states of matter under the given conditions in your answer)

-When 6.53 grams of NH4Cl is dissolved, how many moles of cation are produced?

Calssification and Identification of Aldehydes and Ketones

1.Give a valid structure of a compound that contains the following functional groups:

a. an aldehyde

b. an aromatic aldehyde

c.a ketone

d.a methyl ketone

2. Why can you not distinguish between an aldehyde and a ketone using only the 2,4-dinitrophenylhydrazine reagent?

3. What do you expect to see for a positive Tollens' test? Which class of carbonyl compound gives a positive test result?

4. When would formation of a derivative be a necessary step in this experiment?

When you think of a career in chemistry, you may visualize an older man with grey hair mixing chemicals in a laboratory with a lot of explosions. However, in today’s society there are many nontraditional careers for chemists. For example, chemists are employed as cooks, chemical safety officers, cosmetic chemists, forensic chemists, scientific writers, flavor chemists, medicinal chemists, and in the pharmaceutical and public health industries. This week, you will research a nontraditional career in chemistry. Get started by using the links below:

American Chemical Society. (2015). Chemistry careers. Retrieved from  http://www.acs.org/content/acs/en/careers/college-to-career/chemistry-careers.html  

Royal Society of Chemistry. (2015). A future in chemistry. Retrieved from http://www.rsc.org/careers/future/your-future-chemistry

After reading up on some nontraditional careers in chemistry, select a career that interests you the most. Then, during this unit, address the following in your main post:

●     What is the nontraditional career in chemistry that you selected and why?

●     What are the educational requirements and credentials needed for the career?

●     What type of work environment would you expect to experience on a day-to-day basis for your chosen career?

●     How would you go about entering into this career field? What are some ways in which you could transition into this career field?

●     What skills are most needed for this career field?

●     What might be some of the challenges you would face within this career field?

Cobaloxime Synthesis Questions

1. Given this compound: chloro(pyridine)bis(dimethylglyoximato)cobalt(III)

a) Does this complex contain any chelating ligands? If so, which ones and what is their denticity?

b) Which ligands are monodentate?

c) Which ligands are neutral?

d) Which ligands are anionic?

2. The coordination complex you are making belongs to a family of compounds with a shorthand nickname of “cobaloxime”. Other derivatives of cobaloximes can be made by replacing chloro- and pyridine with other ligands. Cobaloximes have been used as model complexes of the naturally occurring cobalamin, otherwise known as vitamin B12.

a. What makes cobaloximes appropriate models for vitamin B12?

b. What are some differences between cobaloxime and vitamin B12?

1.567 g of an unknown Mohr’s salt was dissolved in 80 mL of the sulfuric acid / phosphoric acid mixture solution. This iron solution was then titrated with a potassium permanganate solution (0.02M), what will be the volume at the equivalence point for the titration? Show all your calculations including formulas.

Write out the characters of the following direct products in D4h symmetry and determine the irreducible representations which comprise them. Show your work in detail. The D4h table can be found online. a. A1g x Eg b. A1u x B2u c. Eg x Eu d. B2g x A1u x B2u

Could plastics be used for the exterior of spacecraft? What are polymer molecules like and what type of intermolecular force(s) hold them in the solid state? When high energy U.V. photons hit polymer chains what might happen (as opposed to shining on a metal)??

An unknown compound contains only C, H, and O. Combustion of 4.90 g of this compound produced 11.5 g of CO2 and 3.15 g of H2O. what is the empirical formula?

At 1 atm, how much energy is required to heat 87.0 g of H2O(s) at –16.0 °C to H2O(g) at 169.0 °C?

Consider these reactions where M represents a generic metal:

2M(s) + 6HCl(aq) ---->2MCl3(aq) + 3H2(g) Delta H1 = -569kj

HCl(g) ----> HCl(aq)   DeltaH2 = -74.8

H2(g) + Cl2(g) ----> 2HCl(g) Delta H3 = -1845kj

MCl3(s) ----> MCl3(aq)   Delta H4 = -405kj

Use the above information to determine the enthalpy of the following reaction:

2M(s) + 3Cl2(g) ----> 2MCl3(s)   What is Delta H for this reaction?

A solution contains 10.75g of an unknown compound dissolved in 50.0 mL of water. (Assume a density of 1.00 g/mL for water.) The freezing point of the solution is -3.38 C. The mass percent composition of the compound is 60.98% C, 11.94% H, and the rest is O.

-What is the molecular formula of the compound?

Express your answer as a molecular formula..

Explain how symmetry arguments are used to construct molecular orbitals.