OBJECTIVE TESTS IN ORGANIC CHEMISTRY* J. W. INCBAND CBcrr, L. BROWN, REODEISLAND STATE COLLEGE. KINGSTON, RHODBISLAND
The use of objective or so-called "short answer" examinations in general chemistry is widespread. Considerable time and ingenuity are required to produce a test of this type that will be the measure one desires. The time involved, however, is compensated for by the ease and exactness obtained in grading the papers. Objective tests for organic chemistry have found less application, possibly because the ways in which they may be applied have not been very apparent. It is the purpose of 'this paper to offer some suggestive samples of tests that have been used in organic chemistry. For convenience the examinations, only portions of which are presented in this article, have been grouped under the general headings of (1) matching, (2) completion, (3) true-false, (4) multiple-choice, and (5) sequence types. It may be mentioned here that the tests represented have been designed to require ten to twenty minutes for answering. For rapidity in grading only one type has appeared on a paper. For longer examinations composites of these have been used.
Matching Type Examples of the first or matching type are shown in Tests 14. In Test 2 the number of names is double the number of formulas. Test 4 shows only a part of the questions a n d of the possible responses.
,
TEST1 Match the item in the first list with the corresponding item in the second list by putting similar numbers in front of each pair. Name
1. 2. 3. 4.
Formula
.... .... . . .. . . ..
Propyl isocyanide Iso hutyramide Tetra me ammon. hydroxide Tri n-butyl amine
(CHl)L!HCONH2 (CHsCH*CHnCH2)3N CH8(CH&NC (CHddNOH
TEST2 Formulas
1. CoH5Br 2. CsHsCsHs 3. CsHaCHl 4. C6HdCHa)l 1.4 1. 2. 3. 4.
.. . . . ... . . .. . . ..
Acetone Bakelite Ethylene glycol Oxalic acid
Names
Cymene o-hrom nitro benzene Diphenyl m-chlor toluene
. .. . .. . . . . .. ....
.. . . .. . . . . .. . .. .
Bromohenzene Hexamethyl benzene 9-Xylene Toluene
Removes iron rust and ink spots Chemical solvent Insulating material Automobile antifreeze agent
* Presented before the Division of Chemical Education of the A. C. S, at Minneapolis, Minnesota, September 12, 1929. 610
TESTS IN ORGANIC CHEMISTRY
VOL. 7, NO. 3
till
TEST4 From the list of substances below record in numerical order the numbers of those corresponding to the questions.
E.
All those that areuseful as a source of heat.
F. All those that are of interest or value in connection with the study of medicine. G. All those that are useful as solvents. 1. 2. 3. 4.
Gasoline Coal Benzene Iadoform
5. Grain alcohol G. Natural fats 7. Kerosene 8. Marsh gas
9. 10. 11. 12.
Chloroform Sterno Woad alcohol Coal-tar dyes
Completion Type Examples of the completion type are shown in Tests -5-13. TEST5 Givc structural formulas for the compounds represented. The methane hydro-
Corre~pandiw alkyl radical
carbon containing
Halogen derivative
Aleahal
.Aldehyde*
Ketone*
Two carbons Four carbons
*Tocontain numlxr of carbons corresponding to hydrocarbon named. TESTG Give as many names as possible for tKe following formulas. Z
a . CHCHSCHCHSCH~
CHs
TEST7 For each of the following formulas supply the specific name of the compound and the class represented by it. Porrnula
a.
b.
Specificname
C ~ ~name E E
CHCHOHCH, CHCOOH
........................
........................
CH,COOH
........................
........................
TEST8 Supply, in the space provided, the names of the reactions illustrated by the equations given.
+
+
CH8C1+ CHaCH2CL Zn +CH,C&CH, ZnCI, CHCHL!OONa NaOH +CHCHa Na2COs
+
+
TEST9 Balance and complete the following equations:
.................... ....................
612
MARCH, 1930
JOURNAL OF CHEMICAL EDUCATION
+
CH4 Clz-+ C&COONa NaOH CHJ Zn --+
+
+
.................... ....................
+
.................... TEST10
Fill in all blank spaces with the name or formula corresponding to that given in the same horizontal line. Common name
Chemical name
Structural formula
Acetylene
.......
......... .........
......
Ethanol
......
.......
CHCh
TEST11 Introduce formulas for the intermediate compounds. Reactant
Intermediate
Product
CHa CzHaBr
.......... ..........
CHZOH C&CH,COOH
TEST12 Supply in the space provided strnctural formulas of compounds which illustrate the term designated. Terms
Compounds
...................... ...................... ......................
Unsaturated hydrocarbon Alkyl group Halogen derivative
TEST13 In each of the following supply the missing words necessary to complete the meaning of the sentence. 1. Decomposition of a substance by heat with accompanying deposition of free carbonisknawnas ............................................................ 2. The majority of carbon compounds are practically insoluble in. 3. Tests furnishing criteria of purity of organic substances are the determination of ................... .in the case of solids and of the.. .in the case of liquids.
.............. .................
True-False Type The use of true-false questions is exemplified in Tests 14-10.
+
TBST14
Indicate by correct answers; by - incorrect answers. PART I. AU asymmetric carbons are shown by *; (
) 'CHOHCOOH
I
(
) *CHOHCOOH
I
CHaCOOH CHOHCOOH PART 11. The following pairs of compounds are isomers: ( ) CHsCHClr and CHKI-C&CI ( (CHnC0OH)r and CHCH(COOH)3
VOL.7, NO. 3
TESTS I N ORGANIC CHEMISTRY
TEST15 ( ( ( (
) ) )
C%OH CHaOCHa CHaCHsCHOHCHa cH%cO\n
Wood alcohol Ordinary ether Tertiary butyl alcohol Acetic anhydride
Mark an x over the number of incorrect statements. 1. An empirical formula represents merely the relative number of atoms of the elements present in a compound. 2. A graphic formula represents the supposed relationship or arrangement of the atoms present in a compound.
Multiple-choice Type Several representatives of the multiple-choice type appear below Draw a line through the correct statement. 1. Coke and charcoal are made by: destructive distillation; burning coal and wood; they are dug from the earth 2. The raining of petroleum is a p r o m s of: destructive distillation; fractional distillation; cracking oils; filtering oils.
From each of the following groups of formulas select those that are identical in structure with the first formula in the group. Draw a line through those selected. CHJCH~CHCHAH~ CHa
Compound
Grain alcohol Wood alcohol
Method of preparation or manufacture
Hydrolysis, oxidation, reduction. or fermentation Oxidation, fermentation, destructive distillation, or fractional distillation
GI4
JOURNAL OP CHEMICAL EDUCATION
MARCH,1930
TEST20 1. Find the formula of that gas which contains 80% C and 20% H . C = 12, H = 1).
(At. wts:
Solution:
C = 80 t 12 = 6.66 H=20+1=20 Answer. CHI, GH,, CdHm CHs, C ~ H MCsHs, , or CIHQ. 2. Given the weight of one liter of propane gas a t N. T. P. as l.9G4 g. the molecular weight can be found by: a. Dividing 1.964 by 1; b. Dividing 22.4 by 1.964; c. Dividing 273 by 1.964; d. Multiplying 22.4 hy 1.964; e. Multiplying l.9fi4 hy 44.
TEST 21 Draw a line through related expressions, synonymous with or suggested by corresponding term in first column. Acid amide, benzene ring, peptid-linking, Van Slyke's Millan's reaction
agent, yellow color
TEST22 Draw a line through the terms thatrare synonymous with, identical to, or related to the expressions given in the first column. Carboxylic acids Racemizing agents
II
Toluic aad, carbohc aad, sulfanilic acid, pyromucic acid, nicotinic acid ' ' Copper sulfate, sodium hydroxide, quinoline, cinchonine
One name is incorrectly used in each of the following groups. Draw a line through this name. I
CHrCHrCH(CHs)GHr Isopentane Me di e t methane Me isobu methane Isohexane Isobu ethane
I1
CHJCH(OH).CH2.CH~ M e e t carhinol Secondary bu alcohol Isapr carbinol Me et hydroxy methane Hydroxy butane (2)
111
CzHsOCHa Me et ether Ordinary ether Me e t oxide Methoxy ethane A mixed ether
TEST 24 There is one incorrect formula or equation in each of the following questions. Draw a line through this incorrect answer.
VOL. i . NO. B
TESTS I N ORGANIC CHEMISTRY
ti15
1. These formulas represent members of the methane series of hydrocarbons: CsH12 b. CLOH~S C. CgHIo d. CLH,O 8 . C.oH,.. 2. These formulas represent esters: a. (GHd3SOa b. CHSCI c. C%HsCOOGHs d. CHaCOCl e. C2H;HS04 a.
Sequence Type Two examples of the sequence type are given in Tests 23 and 2G
A . To produce butyric acid from the ethyl ester of malonic acid one may pass through these steps. Number them in order. . . Saponification . . .Heat t o remove C02
. . . .AddNa . . . .Add CnH6Br
A . To obtain pure crystals from some impure material these steps may be carried out. Number them in proper sequence.
. . .Melting-point determination . . . Choosing solvent . . . .Removal
. . . .Fractional crystallization . . . .Removal of residual solvent of insoluble impurities
These tests are of course only suggestive of the various modifications which the objective examination may take in organic chemistry. By analysis of the subject matter to be covered, practically every portion of this branch of chemistry can be included in questfons of the above types.
Reducing Dust Hazard of Granite Industry. Removal of air a t a speed of 1.500 feet per minute, measured a t the surface of the ventilating hood, is the standard for ventilating systems that will reduce the dust in the air of granite plants to a safe level, the U. S. Public Health Service has announced as the result of its studies just completed. Dust in the various operations of the granite industry has long heen a scn'ous hazard to workers' health. The disease of the lungs known as silicosis was found to develop as a result of prolonged exposure to the granite dust through long periods of employment. Previous studies showed that when the air which the operator breathed had less than 10 million particles of dust per cubic foot of air, it was safe. Certain of the granite-cutting plants had ventilating systems which provided sufficient ventilation to make the plants safe for the workers when the systems were properly operated, the recent investigations showed. Besides studying the ventilation systems in operation, the U. S. Public Health Service conducted an experiment to determine the exhaust velocity necessary a t the ventilating ducts to keep the dust dawn t o a safe limit. As a result of the experiment, the safe limit of exhaust velocity was determined to be 1500 feet per minute.-Science Service
