CHEM 132L Lecture Notes - Lecture 2: Viscosity, Naphthalene, Pipette

44 views6 pages

coralchimpanzee997

8 Jun 2018

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Name: Isbah Afzal

Lab partner: Alexis

Lab Section Number: 001

Experiment title: Intermolecular Forces

Due date: 09/22/2017

PART C

Di H2O

Ethanol

Hexane

Butyl

Acetate

Ethylene

Glycol

DIH2O

Miscible

Prediction:

The

prediction

was that the

solution

would be

miscible

because the

solvent and

solute were

completely

dissolved.

Immiscible

Prediction:

The

prediction

was that the

solution

would be

immiscible

because

hexane is an

organic

compound

and

insoluble in

water.

Immiscible

Prediction:

The

prediction

was that

Butyl acetate

would be

immiscible

in water

because it is

non-polar

and water is

a polar

compound

Miscible

Prediction:

Ethylene

Glycol is a-

water like

solvent

therefore it

easily

dissolves in

water.

Ethanol

Immiscible

Prediction:

the solution

was

predicted to

immiscible

because

ethanol is

polar and

hexane is

non-polar

Miscible

Prediction:

ethanol can

dissolve in

both polar

and non-

polar

substances.

Miscible

Prediction:

The

solution

was

predicted to

be miscible

because

Ethanol

and

Ethylene

Glycol are

polar.

Hexane

Immiscible

Prediction:

Prediction

was that the

solution

would be

Immiscible

Prediction:

The

solution

was

predicted to

find more resources at oneclass.com

Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

miscible

because

hexane and

butyl acetate

is non-polar.

Like non-

polar

compounds

dissolve in

each other.

immiscible

because

Hexane is

non-polar

whereas

Ethylene

Glycol is

polar.

Butyl

Acetate

Immiscible

Prediction:

predicted to

immiscible

because

Butyl

Acetate is

non-polar

and

Ethylene

Glycol is

non-polar.

Ethylene

Glycol

PART D

KMnO4

Sucrose

Iodine

Nickle

Sulfate

Hexahydrate

Naphthalene

DIH2O

Solution

turned dark

purple

Clear with

solid grains

settled at the

bottom

Muddy

brown color

with black

solid at the

bottom.

Light blue

water in

color.

Translucent

with solid

particles

settled at the

bottom.

Clear with

thick solid

floating.

Hexane

Clear with

solid

particles at

the bottom.

Clear with

thick grains

stuck at the

sides of the

bottom.

Turned dark

purple.

Clear water,

crystallized at

the bottom.

Clear with

solid at the

bottom.

find more resources at oneclass.com

Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

Document Summary

The prediction was that the solution would be miscible because the solvent and solute were completely dissolved. The prediction was that the solution would be immiscible because hexane is an organic compound and insoluble in water. Prediction: the solution was predicted to be immiscible because ethanol is polar and hexane is non-polar. Butyl acetate would be immiscible in water because it is non-polar and water is a polar compound. Prediction: ethanol can dissolve in both polar and non- polar substances. Glycol is a- water like solvent therefore it easily dissolves in water. The solution was predicted to be miscible because. The solution was predicted to miscible because hexane and butyl acetate is non-polar. Like non- polar compounds dissolve in each other. Clear with solid grains settled at the bottom. Muddy brown color with black solid at the bottom. Clear with thick grains stuck at the sides of the bottom. Translucent with solid particles settled at the bottom.

Related Questions

Preparation of acetyl salicyclic acid (Aspirin) post-lab questions

1.)At the end of the reaction, you were asked to add ice-cold water to the reaction mixture. What do you think is the reason for this? Explain with chemical equations.

2.)How would the % yield of aspirin be changed if the final rinse of the solid product on the filter paper was done with warm water instead of ice-cold water?

3.)If you run a thin-layer chromatography for a mixture containing salicylic acid and aspirin using a 1:1 solvent mixture of ethyl acetate and hexane, which compound do you think would have more R_f value. Explain why? Bring in the structural features in your explanation.

summary Procedure of lab we did:

- Place approximately 0.300 g of salicylic acid in a tared empty 5 mL conical reaction vial. Record the actual weight of salicylic acid used. Using automatic pipet, add 0.8 mL of acetic anhydride (acetic anhydride vapors are very irritating-handle it carefully, in the hood). Add 2-3 drops of concentrated sulfuric acid using a dropper.

-Clamp the assembly so that the vial is partially submerged in the hot water. Turn on the magnetic stirrer. Once the water bath starts boiling, start timing the reaction. When the mixture has been allowed to react at 100 oC (the temperature of boiling water) for 15 minutes, you can consider the reaction to be complete. During the heating time, take about 20 mL of deionized water in a flask and chill it in an ice-water bath.

- After the reaction has gone on for 15 minutes, add very cautiously, drop by drop, 1 mL of deionized water to the reaction vial. At this point you should have a solution in your reaction vial. Remove the reaction vial form the hot water bath, add another 1-2 mL of DI water and let it stand at room temperature for few minutes. Then, detach the air condenser carefully and remove spin vane with forceps. Place the vial in a beaker and cool down to RT. During this time, the aspirin may begin crystallizing. If not, scratch the walls of the vial with a glass rod. Then, cool the vial in an ice-water bath.

- When the vial appears full of crystals, add about 3-4 mL of ice-cold DI water. Filter the aspirin using vacuum filtration (use Hirsch funnel). Leave the filtration setup in place for few minutes-this will draw air through the sample and will help dry aspirin.

Recrystallization of Aspirin:

- Transfer the rest of the crude aspirin to a 25 mL Erlenmeyer flask and do recrystallization using ethanol.

Purity of Aspirin:

- Using the melting point apparatus, determine the melting point of your crude aspirin and the recrystallized aspirin.

- To do FeCl3 test, get 4 test tubes. Place 1 mL of ethanol and 2 drops of 1% FeCl3 solution in each test tube. Add few crystals of salicylic acid to one test tube. Add few crystals of your crude aspirin product to the second test tube. In the thirst test tube, place a few crystals of your recrystallized aspirin. The fourth test tube will be your âblankâ. Shake each of the test tubes and record your observations.

2.) Bart was a truly superb organic laboratory student. Unfortunately, his partner Homer was a bit careless. Bart was carefully saving solid samples of benzoic acid and ethyl-4-aminobenzoate in his lab locker; he needed to run melting point determinations on these samples after they had dried for a week. Before he got a chance, Homer picked up both samples, dumped them together in a beaker, and was about to carry them to a waste jar. Bart recovered the beaker, and decided he could easily separate the two components. How would Bart best recover the ethyl-4-aminobenzoate from the solid mixture ?

a. Dissolve the solid mixture in ether, extract the ether solution with 10% aqueous sodium hydroxide, collect the aqueous layer and add an acid.

b. Dissolve the solid mixture in ether, extract the ether solution with 10% aqueous hydrochloric acid, collect the aqueous layer and add a base.

c. Dissolve the solid mixture in ether, extract the ether solution with 10% aqueous sodium hydroxide, collect the ether layer and let the ether evaporate.

d. Dissolve the solid mixture in ether, add about the same volume of water, shake, separate and discard the aqueous layer, let the ether layer evaporate and collect the product.

3.) After Bart separated the benzoic acid + ethyl-4-aminobenzoate mixture, he recorded nujol mull IR spectra for the separated materials, as well as for some naphthalene he had in his locker. The resulting spectra are in Figure 1. Which spectrum is most likely the spectrum of benzoic acid ?

A) Fig 1-A B) Fig 1-B C) Fig 1-C D) Fig 1-D

E) None of the spectra are a good match

4. ) Bart also had vials of acetone, chloroform, and toluene which Homer dumped into another waste beaker. Bart sees no problem, he thinks he can separate this mixture also. What technique would be his best choice ?

A.) recrystallization

B.) simple distillation C

.) fractional distillation

D.) column chromatography with an alumina stationary phase

5.) If the 3-component mixture of problem 4 were injected into a gas chromatograph, which component would have the shortest retention time ? ( assume a helium carrier gas, a non-polar stationary phase, injector and t.c. detector at 150 C, column at 75 C )

A) Acetone

B) Chloroform

C) Toluene

D) There is not enough information provided.

E) The components are not likely to separate under the conditions described.

6.) Which of the following statements about the Diels-Alder reaction is FALSE ?

A) It is a [2+4] cycloaddition.

B) It is a reaction involving pi-electrons.

C) It is a concerted reaction.

D) It is a reaction favored by entropy considerations.

E) It is a thermal reaction.

7.) When the following two molecules combine by a Diels-Alder reaction, the product will contain two new sigma bonds between atoms which were not previously bonded. Between which pairs of atoms will these bond be formed ?

A) b-d and f-g

B) j-k and o-m

C) b-k and g-m

D) d-k and f-m

E) b-j and g-o

8.) Bart and Homer have returned to the lab. They are trying to run a Diels-Alder reaction, starting with 4.80 grams of cyclohexadiene (MW 80.13) and 5.88 (MW 98.06) grams of maleic anhydride. At the end of the reaction, Homer recovered 7.38 grams of the adduct, but has no idea what to report as a percent yield. Bart pulls out a calculator and quickly comes up with a number. What was the percent yield he calculated ? (Choose the closest answer, within 1 % )

A) 79.7 % B) 69.2 % C) 65.0 % D) 45.5 %

E) None of the above choices are close ( i.e. within 1% )

9.)Which of the following statements is FALSE about the experimental process used in the Diels-Alder reaction?

A) Glassware should be washed and rinsed with hot tap water immediately before adding reagents.

B) Maleic Anhydride is toxic.

C) The product may be recrystallized from the methanol solvent.

D) The I.R.'s of the product is different from maleic anhydride

E) No flames are used during this reaction.

10.) Suppose you have determined a GC spectrum for a sample oil containing an unknown diene. You are preparing to run a Diels-Alder reaction using this oil. You find 3 peaks. From determination of peak area, you find that the percent compositions represented by the peaks are: peak A is 55 percent , peak B is 30 percent, and peak C is 15 percent. The M.W. of your diene is 136 g/m. How many grams of Maleic Anhydride (M.W. 98 g/m) will you use to react with your 2.5g sample of crude diene? (The largest GC peak is the diene)

A) 0.99 B) 1.25 C)1.375 D)1.91 E)2.5

11.) In the proton NMR of ethyl acetate, which group of hydrogens would appear the most upfield ?

A. A

B. B

C. C

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?

A. 32.1

B. 66.5

C. 77.0

D. 88.6

E. None of the above are correct (within 1%)

CHEM 132L Lecture Notes - Lecture 2: Viscosity, Naphthalene, Pipette

Document Summary

Get access

Related textbook solutions

Chemistry: Structure and Properties

Basic Chemistry

Principles of Chemistry Molecular Approach

Principles of Chemistry Molecular Approach

Chemistry: Structure and Properties

Chemistry: A Molecular Approach

Chemistry: A Molecular Approach

Principles of Chemistry: A Molecular Approach

Chemistry: The Central Science

Related Documents

CHEM 1201 Chapter : Chapter 13 Lecture

CHEM 102 Midterm: CHEM 102 Drexel CHEM 102 Exam 3 WINTER 09 10 with answer key

CHEM 102 Lecture Notes - Lecture 3: Mole Fraction, Miscibility, Molality

Related Questions