For part A) why is the student unable to do both parts simultaneously?
And for part B) what parts of the procedure should the student not carry out on his bench?
re-Laboratory Assignment 1. A student wanted to rush through the laboratory work for this experiment. In order to do so, he set up the equipment for Parts I and IV of the Procedure on his laboratory bench so he could do both Parts simultaneously. His laboratory instructor asked him if what he was preparing to do was safe. He told the laboratory instructor it was, because he was wearing safety goggles. The instructor told the student to put his equipment away and reread the Procedure. (a) Why did the laboratory instructor stop the student from performing Parts landâ £ simultaneously on his laboratory bench? (b) What Part(s) of the Procedure, if any, should the student not carry out on his laboratory bench? Briefly explain. 2. Briefly explain what is meant by each of the following terms as it relates to this experiment. (a) complete ionic equation-
12.) In the proton NMR of ethyl acetate, which group of hydrogens is the most magnetically shielded?
A.) A
B.) B
C.) C
13.) Rank the proton groups of the ethyl acetate molecule in order of increasing chemical shift.
A.) BAC B.) CAB C.) ACB D.) BCA
14.) Which of the following could happen when infrared radiation is absorbed by a molecule ?
Electrons are promoted from filled to empty molecular orbitals
The orientation of a nuclear spin state changes.
Intra-molecular bond angles change
molecule begins to rotate more rapidly
molecule may glow in the dark
15.) Infrared absorption spectra of organic molecules are often presented as a plot of transmittance versus wavenumber. What is the definition of a wavenumber ?
one wavenumber = one micron
one wavenumber = one centimeter
one wavenumber = one reciprocal micron
one wavenumber = one reciprocal centimeter
wavenumber is the same as wavelength, and can be expressed in any unit of length
16.) Which bond would you expect to have the highest vibrational frequency (stretching) ?
A) Urea
B) Sodium Carbonate
C) Potassium Iodide
D) Sulfuric Acid
E) Sodium Nitrite
Questions 17 through 20 are spectra identification problems. You must identify two unknowns, referred to as compound A and compound B. Table I, attached at the end of the exam, has a list of possible compounds. Each compound listed in table I has a two digit identification code. After you have identified compound A, you will enter the first digit of its identification code as the answer for question 18, and then enter the second digit of the code as the answer for question 19. You then repeat this process for compound B in questions 20 and 21.
17.) Compound A gives a positive acetyl chloride test, and the infrared and NMR spectra are given in figures 2A thru 2C. Consult table I and the spectra, identify compound A. The first digit of the code corresponding for compound A is
A) 1 B) 2 C) 3 D) 4 E) 5
18.) The second digit of the code for compound A is
A) 1 B) 2 C) 3 D) 4 E) 5
19.) You have run a series of qualitative chemical tests on compound B, all of which came out negative. The negative chemical tests included acetyl chloride, chromic acid, potassium permanganate, silver nitrate, and 2,4-dinitrophenylhydrazine. The infrared and NMR spectra of compound B are given in the attached figures 3A thru 3C. Identify compound B. The first digit of the code in table I corresponding to compound B is
A) 1 B) 2 C) 3 D) 4 E) 5
20.) The second digit of the code for compound B is
A) 1 B) 2 C) 3 D) 4 E) 5
21.) Which of the following statements regarding Grignard reagents is FALSE ?
A. The Grignard reagent is an example of an organometallic compound.
B. Grignard reagents are stable in anhydrous ether solutions.
C. A Grignard reagent contains electrophilic carbon.
D. Once prepared , a Grignard reagent should be used quickly.
E. Grignard reagents tend to act as Bronsted bases.
22.) Suppose that in the synthesis of benzoic acid , a student uses 1.215 grams of magnesium , 7.575 grams of bromobenzene , and 22.641 grams of dry ice. If the mass of benzoic acid obtained were 4.530, what was the percent yield?
