Research: Science & Education
National Curriculum Survey of College General Chemistry (1993) Hessy L. Taft Educational Testing Service, Princeton, NJ 08541 The Advanced Placement (AP) Program of the College Board (CB) is a national educational effort that offers secondary school students the opportunity to pursue collegelevel studies. In 1994, nearly 2,900 colleges and universities in the U.S.A. and other countries granted credit, appropriate placement, or both to students who performed satisfactorily on AP examinations. More than 30,000 students, representing 3,385 secondary schools in the U.S.A. and 30 foreign schools, took the AP Chemistry Examination in 1994. The Advanced Placement Course Description for Chemistry is a College Board publication that provides an outline of the topics typically covered in the college general chemistry courses that the AP chemistry course is intended to emulate. In 1985–86, the College Board carried out an extensive survey to assess the content validity of the AP chemistry course (1). As a result of that study, the AP chemistry course description and its final examination were modified to reflect the course objectives prevalent at a broad spectrum of postsecondary institutions (2). On the recommendation of the Test Development Committee for AP Chemistry, the College Board sponsored another national curriculum survey in 1993 to determine, by comparison with the 1986 data, the extent to which the current reform movement in science education had influenced the teaching of college general chemistry courses for science and engineering majors (1). The Task Force for General Chemistry Curriculum of the ACS Division of Chemical Education, charged with recommending appropriate measures for reform in the introductory college chemistry course, was supportive of and contributed to the survey. The results obtained regarding format and organization of the courses for the colleges and universities that participated in the 1993 survey have been reported elsewhere (3). This paper focuses on the content coverage of general chemistry for science and engineering majors, both in the classroom and in the laboratory, as reported by leading U.S. colleges and universities. Figure 1. Parts 1–12 show percentage of faculty reporting coverage of topics in general chemistry courses ( N = 164). E = extensive coverage, M = moderate coverage, B = brief coverage, Np = not covered because prior knowledge assumed, and Ni = not covered because inappropriate. The percentages shown in the title bars represent the average percentage of time for a 1-year course. 1. Stoichiometry & Chemical Equations (10.1%a) Content Area The mole concept and Avogadro's number Empirical formulas and molecular formulas
Coverage (%) E
M
B
60
21
13
43
37
13
Np Ni 4 5
0 0
Significance of balanced chemical equations 57
27
10
4
0
Percentage composition
42
20
4
0
Stoichiometric calculations Limiting reagent and yield of product aRange:
32 71 47
16 34
7 12
4 5
0 0
Survey Participation In 1993, survey forms designed to obtain information on college general chemistry courses were sent to the 270 U.S. colleges and universities that receive 10 or more AP chemistry students per year; 166 completed surveys were returned, a 60% participation rate. (Two surveys were received too late to be included in the tabulated results.) Of these, 86 institutions were private colleges and universities and 80 were public universities. There were 24 small private colleges among the participating institutions; the rest were larger public or private universities. Of the institutions that participated in the study, 45% were from the East, 22% from the Midwest, and 33% from the West of the U.S.A. Results and Discussion The relative coverage of the major content categories for the general chemistry courses at participating institutions are summarized in Figure 1. The responses from institutions indicating the level of coverage for each subtopic within the broad content area are given as a percentage of the total number of respondents. While the descriptions for relative coverage (extensive, moderate, and brief) are qualitative and thus subjective, the Test Development Committee for AP Chemistry judged that attempts to request that faculty members quantify their coverage of topics with percentage ranges would not produce more meaningful results. Not only would the data be as subjective as the qualitative data, but the depth of knowledge expected could be masked because such knowledge need not be proportional to the time devoted to the topic. For example, the mole concept and Avogadro’s number were noted as extensively covered by an overwhelming proportion of institutions; but the amount of time needed to familiarize students with these ideas at the introductory level is not extensive, even though
2. Atomic Theory & Structure of Atoms (10.9%a) Content Area
Coverage (%) E
M
B
Np
Evidence for atomic theory
18
46
30
4
0
Structure of atom
49
39
9
2
0
Atomic spectra
21
47
28
1
1
Quantum mechanics models
17
43
32
5
0
Electron configurations
61
34
2
1
0
Periodic properties
58
36
4
0
0
9
50
37
1
2
Radioactive decay
12
41
30
2
12
Half-life
13
41
30
1
10
Equations for nuclear reactions
10
31
34
1
20
5
23
45
2
20
Isotopes
Applications of nuclear chemistry a
Ni
Range: 1–30% (27 blank) (1–5: 17; 6–10: 77; 11–15: 34; >15: 9).
0–39% (27 blank) (0: 1; 1–5: 27; 6–10: 49; 11–15: 46; >15: 14).
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595
Research: Science & Education the concept is applied constantly throughout the course. Note that when a topic was reported as “not covered”, the survey required an explanation as to whether the content was deemed inappropriate for the course or prior knowledge of the topic was assumed. In some cases, no response was given for a particular topic so that the total responses of coverage reported for a topic may be less than 100% (164 institutions). Figure 1 also provides information on the percentage of time spent in the course on each of the broad content areas. It is pertinent to note that 26–29 of the 164 participants did not respond to the question of how much time they allocate to each major content area in their courses, even though they did respond to the levels of coverage for the specific subtopics (see Fig. 1). From the ranges obtained, it is clear that there is considerable variation in the amount of time different instructors spend on individual topics. However, as noted above, standards for the sophistication
of knowledge expected and the instructional time spent on acquiring that knowledge are not necessarily correlated. Factors such as student background and assignments of homework and independent study contribute to the relative time instructors devote to each topic, but such factors were beyond the scope of this study. For the purposes of this study it was of interest to compute the average percentage of class time spent on the various content areas (Fig. 1). Generalizing from the data, one notes the following not unexpected results: about 10% of the course is devoted to the introductory concepts of stoichiometry and chemical equations; more than 20% of the course is devoted to the study of structure of matter and chemical bonding; acids and bases (Brönsted–Lowry) and equilibrium are the most extensively covered topics among the remaining content areas. The number of schools that indicated brief coverage for inorganic descriptive chemistry is perhaps also not unexpected.
3. Chemical Bonding (11.6%a)
6. Solutions (5.6%a)
Coverage (%)
Content Area
E
Types of bonding (ionic, covalent, hydrogen, van der Waals)
M
B
Np Ni
55
35
5
1
0
Metallic bonds
5
22
61
0
7
Lewis structure
71
24
2
0
0
Resonance
21
55
20
0
0
Valence shell e-pair repulsion model
61
31
4
0
1
Geometry of molecules
66
29
2
0
1
Hybridization
34
46
13
1
3
Molecular orbitals and energy diagrams
13
27
34
0 20
Sigma and pi bonds
27
45
21
0
Polarity of bonds
35
Born–Haber cycle Lattice energies Geometry of coordination compounds Structural isomerism Dipole moments
39
0
0 20
27
46
0 15
32
30
0 21
12
29
38 51 49 48
33 29 12 20
0 12 0 0 0
E
B
Np Ni
Factors affecting solubility
22 4 8
27
1
0
Methods of expressing concentrations
51 3 2
11
3
1
Colligative properties of nonelectrolytes
30 4 5
15
1
5
Colligative properties of electrolytes
16 4 4
29
1
1 0
M
5
a
Range: 0.3–15% (27 blank) (10: 2).
7. Acids, Bases, and Salts (7.7%a) Coverage (%)
Content Area
E
B
Np Ni
Arrhenius concept of acids and bases
29 3 8
27
2
2
Brönsted–Lowry concept of acids and bases
63 2 9
4
1
1
Lewis concept of acids and bases
23 4 3
29
1
2
9 38
49
1
1
Acid–base indicators
12 4 9
35
1
2
Titration curves
34 4 3
16
1
3
0
6
35
Relation of properties to bond type
29
11
12 15
Electronegativity aRange
7
51
3
Coverage (%)
Content Area
Amphoterism
aRange:
1
M
0.3–20% (27 blank) (10: 16).
5–50% (27 blank) (5–10: 75; 11–15: 42; 16–20: 17; >20: 3).
4. Proper ties of Gases & Kinetic–Molecular Theory (5.5%a) Coverage (%)
Content Area
B
8. Chemical Equilibrium (12.2%a)
E
M
Np Ni
Gas laws
54
30
6
4
1
Kinetic molecular theory
24
51
15
2
2
Partial pressures
23
48
20
2
2
Deviations from ideal behavior
9
32
45
1
9
Maxwell–Boltzmann distribution
3
26
51
1 14
a
Range: 0–15% (27 blank) (0: 6; 10: 2).
5. Liquid & Solid States (4.7%a) Content Area
Intermolecular forces
Coverage (%) E
M
B
41 43 12
Np Ni
0
2
Content Area
Coverage (%) E
M
Concept of dynamic equilibrium
59
30
B 9
Np Ni 0
0
LeChâtelier's principle
57
34
6
0
0
Equilibrium constants, Kc , gaseous reactions
45
34
13
0
5
Equilibrium constants, Kp , gaseous reactions
37
41
18
0
2
Ionization constants of acids and bases
65
29
4
0
0
pH and pOH
66
24
7
0
0
pK
45
33
19
0
1
Hydrolysis
43
42
10
0
2
Common-ion effect
44
40
13
1
1
52
35
7
1
2
Phase diagrams for 1-component systems 21 39 26
1 10
Buffers
Critical temperature and pressure
0 12
Solubility products
49
32
13
1
2
0 13
Criteria for precipitation or dissolution
29
40
24
1
2
Structure of solids
5 28 5 2 18 35 30
a a Range:
596
0–10% (26 blank) (0: 10; 15: 16.
Research: Science & Education
9. Oxidation–Reduction & Electrochemistry (7.5%a) Coverage (%)
Content Area
E
M
B
Oxidation states of elements
39
43
13
Np Ni 1
0
Balancing redox equations
45
41
8
2
1
Common oxidizing and reducing agents
12
52
30
0
1
Electrolytic cells
33
49
10
1
3
Galvanic cells
41
41
10
1
3
Electrode potentials
43
42
8
0
4
Faraday's laws
22
51
20
0
4
Nernst equation
31
46
13
0
6
a
Range: 0–20% (28 blank) (0: 2; 1–5: 36; 6–10: 92; 11–15: 4; >15: 2).
10. Chemical Kinetics (6.6%a) Coverage (%)
Content Area
E
M
B
Np Ni
Factors affecting rates of reactions
49
38
9
0
0
Arrhenius equation
26
47
20
0
2
Determining reaction order & rate constant
48
38
8
0
2
Catalysis
18
46
30
0
2
Energy of activation
31
51
13
0
1
Mechanism of reaction
24
43
27
0
2
a
Range: 0–20% (28 blank) (0: 1; 1–5: 62; 6–10: 66; 11–15: 6; >15: 1).
11. Chemical Thermodynamics (9.2%a) Coverage (%)
Content Area
E
M
B
Np Ni
First law of thermodynamics
41
40
12
0
State functions
27
39
24
0
4
Hess's law
54
33
7
1
1
2
Enthalpy changes for chemical reactions
62
29
4
0
1
Standard states
25
44
24
1
2
Heats of vaporization and fusion
17
55
21
1
2
Heats of solution
13
38
40
0
4
Spontaneous and reversible processes
42
41
10
0
2
Entropy and entropy changes
43
42
9
0
1
Free energy changes
45
38
9
0
3
Free energy dependance on enthalpy and entropy changes
41
40
11
0
3
Relationship of free energy, cell potential, and equilibrium constant
35
36
18
0
5
aRange:
0–55% (26 blank) (0: 2; 1–5: 20; 6–10: 89; 11–15: 23; >15: 4).
12. Descriptive Chemistry (7.8%a) Content Area Alkali metals & their familiar compounds Alkaline earth metals & their familiar compounds Nitrogen & its familiar compounds Phosphorus & its familiar compounds Properties of hydrogen and oxygen Sulfur & its familiar compounds
Coverage (%) E
M
B Np Ni
1 3 3 2 40
2
4
9 3 3 40
2
6
2
9
1 0 3 0 38 6 2 4 42 15 29 35 7 2 8 38
3 13 3
7
4 11
Halogens & their familiar compounds
14 41 29
1
Transition metals & their familiar compounds
15 34 29
1 13
aRange:
5
0–36% (29 blank) (0: 16; 1–5: 46; 6–10: 41; 11–15: 20; >15: 12).
It may be more surprising to note that about 10–20% of the participating institutions judged topics such as molecular orbitals, Born–Haber cycle, geometry of coordination compounds, lattice energies, structure of solids, Maxwell– Boltzmann distributions, phase diagrams, critical temperature and pressure, and nuclear chemistry applications as inappropriate for first-year college chemistry courses. These findings may provide some evidence that the oft-cited criticism of general chemistry as a “baby p-chem” course is beginning to take effect. Also, the topics of structural isomerism and the descriptive chemistry of group V and VI elements and transition elements were deemed inappropriate by 11–13% of the participants. Thus, 84 of the 100 topics listed in Figure 1 were judged as appropriate for general chemistry courses by 80–90 % of the participants. The topics given in Figure 1 have traditionally been part of the majority of general chemistry courses nationwide, and as such they constituted the basis for the course descriptions for AP chemistry through 1994 (2). The survey conducted in 1993 sought, in addition, to obtain information on the extent to which other areas of chemistry were covered in college general chemistry courses. The topics listed in Table 1 have typically been taught less frequently in first-year courses, but were suggested by the Test Development Committee for Advanced Placement Chemistry after consultation with other college faculty and several college textbooks intended for the introductory chemistry course for science and engineering majors. Not all 164 survey participants responded for every one of the 20 content categories listed in Table 1. It may be that respondents checked only the categories for which there was some coverage. Because some entries were left blank it was not always clear whether a topic received no coverage or whether the coverage was simply not recorded. Thus it is worth noting that about half of the participants discussed hydrocarbons and functional groups of organic compounds at the moderate or extensive level in their courses. The extent of coverage at the “extensive” level for hydrocarbons and functional groups increased by 3–4% from that reported in the 1986 study (1). Similarly, in the general chemistry course for majors, the attention given to environmental chemistry and the chemistry of materials and polymers is also a departure from earlier practice. In 1985–86, coverage of environmental chemistry was reported as extensive in less than 1% of participating institutions and moderate in 42%; coverage for polymers was extensive in less than 1% and moderate in 35%; no institution reported extensive coverage of societal issues in chemistry, and 29% reported moderate coverage (Taft, H. L., unpublished results; national curriculum survey of college general chemistry courses, 1986). Nevertheless, the only topics listed in Table 1 for which extensive coverage was reported by about 15% of respondents were those pertaining to organic chemistry. Faculty were not asked to provide data on the percentage of time devoted to the topics in Table 1. However, from the broad range of times reported in Figure 1 for each major content area of the general chemistry course, it is reasonable to infer that faculty spending less than average time on some particular content area or areas had time to address these topics in their courses. Also, some of the 26– 29 participants who did not respond to the question regarding time allocated to specific topics could be among those who are covering some of the topics in Table 1. In response to a question regarding the textbooks used in college general chemistry courses, the participants provided the following data. In 1993, 37% of the general chemistry courses surveyed were using the following three books
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Research: Science & Education as their primary textbooks, in approximately equal proportions: Brown, LeMay, and Bursten, Chemistry: The Central Science (Prentice Hall); Chang, Chemistry (Random House/ McGraw Hill); and Zumdahl, Chemistry (Heath). An additional 20% of respondents indicated that the major textbooks in their courses were (also in approximately equal proportions): Ebbing, General Chemistry (HoughtonMifflin), Kotz and Purcell, Chemistry and Chemical Reactivity (Saunders); and McQuarrie and Rock, General Chemistry (Freeman). The remaining 43% of the survey participants listed seventeen additional books as the major texts on which their college general chemistry courses were based. Table 2 summarizes the laboratory practices and specific experiments to which students in college general chemistry courses are exposed and the manner in which the laboratory is presented. Participants were also asked to list other common experiments or demonstrations carried out in courses for chemistry and engineering majors. By far the most common were the synthesis and purification or the analysis of an organic compound, again representing a shift from data obtained in the 1986 survey (1). It is interesting that the microscale laboratory does not contribute significantly to the laboratory in college general chemistry courses. The data in Table 3 indicate that the student-produced laboratory report was universally acknowledged to be the primary basis for evaluating laboratory performance. In addition, more than half of the colleges surveyed indicated that written examinations contributed to the grades assigned for laboratory work and about one fourth gave laboratory practical examinations to evaluate laboratory performance.
Table 1. Coverage of Additional Content Areas in College General Chemistry Courses for Majors a Coverage Content Area Exten- Cov- None sive ered (%) (%) (%) Hydrocarbons (structure & nomenclature)
16
35
5
Functional groups of organic molecules
13
32
5
Addition reactions-organic compounds
5
24
6
Substitution reactions-organic compounds
5
21
7
Structures of biological molecules
2
23
7
Colloids
0
25
4
Polymers
4
42
6
Chemistry of materials
2
37
5
Environmental chemistry
4
57
3
Societal issues in chemistry
2
41
4
Properties of lanthanides and actinides
0
7
7
Nuclear magnetic resonance (imaging)
1
9
6
Schrodinger equation
2
36
6
Van der Waals equation
3
58
3
Activities of ions in solutions
1
20
5
Free energy changes in nonstandard states
2
25
6
Clausius-Clapeyron equation
3
45
4
Ligand field theory
7
36
2
Dry cells and storage batteries
1
55
3
Fuel cells
2
50
4
a
N = 164, but because not all participants responded for each category, the total is < 100%.
Table 2. Common Laboratory Experiments in College General Chemistry Coursesa Student Lab
Microscale Lab
Experiment
Lecture Video Demon- Presenstrationb tationb
Yes
No
Yes
No
116
31
3
52
8
—
Determining the percentage of water in a hydrate
87
55
1
43
5
—
Determining molecular weight by vapor density
67
81
—
41
3
1
Determining molecular weight by freezing-point depression or boiling-point elevation
74
66
1
38
3
1
Determining the molar volume of a gas
61
74
1
36
4
—
Determining the formula of a compound
Determining concentration by acid–base titration
153
3
4
59
6
3
Determining concentration by oxidation–reduction titration
108
34
3
44
7
2
Standardizing a solution using a primary standard
121
25
2
51
3
2
Determining weight and mole relationship in chemical reactions
124
15
3
51
6
—
Determining the equilibrium constant for a chemical reaction
117
26
10
47
9
1
90
50
5
44
13
2
Determining the rate of a reaction
129
19
7
52
10
4
Determining enthalpy change associated with a reaction
127
22
2
53
11
2
Separation and qualitative analysis of cations and anions
121
24
18
39
5
4
86
54
5
37
3
2
88
55
1
41
3
1
133
16
4
50
6
5 —
Determining appropriate indicators for acid–base titrations; pH determination
Synthesis of a coordination compound and its chemical analysis Analytical gravimetric determination Colorimetric or spectrophotometric analysis Paper chromatography
56
80
4
30
7
Preparation and properties of buffer solutions
73
64
2
39
9
1
Determining electrochemical series
63
72
5
28
8
—
Measurements using electrochemical cells
77
65
4
36
6
4
a Total b “Yes”
598
responses = 164, but not all participants responded to all items. responses to covering experiment by this method.
Journal of Chemical Education • Vol. 74 No. 5 May 1997
Research: Science & Education As reported by Taft in the survey summary on course organization (3), the laboratory portion of the college general chemistry course requires separate registration for about 45% of the courses surveyed. As for time dedicated to the laboratory, 60% of respondents reported that 2.5–3 hours per week were allocated for the laboratory portion of general chemistry, whereas 30% reported that more than 3 hours per week were devoted to this activity (see Table 4.) Since the majority of the AP chemistry courses allot 45–55 minutes per week to the laboratory, the time devoted to the laboratory is the biggest discrepancy between AP chemistry and the corresponding college general chemistry course. The data obtained reinforce the importance of disseminating more clearly the message that more time needs to be allocated to the laboratory when scheduling AP chemistry courses in secondary schools. Some progress in this regard is becoming evident: some schools have in place at least one 90-minute period per week and some have even longer periods, but such practices need to become more widespread if AP chemistry students in high schools are to be offered an experience similar to that provided by the college general chemistry course (4). To facilitate the implementation of a reasonable laboratory program for AP chemistry, recent AP chemistry course descriptions have included a “Guide for the Recommended Laboratory Program”, which provides suggestions for minimum time and equipment needed for standard college general chemistry experiments (2, 5). Finally, it should be noted that about 2–3% of the colleges and universities surveyed in this study reported that the general chemistry courses at their respective universities had already departed so significantly from the traditional college general chemistry course that the survey was applicable to their courses only for reporting the chemistry principles taught. These institutions pointed out that the survey did not reflect the sequence in which different areas of chemistry were taught or the pedagogical approaches employed to accomplish the desired learning. Furthermore, the emphasis in reported coverage of specific content for these chemistry courses deviated significantly from the range of coverage reported for the large majority of institutions. Conclusions The major findings from the national survey of college general chemistry courses at colleges and universities receiving significant numbers of AP students annually are the following. The college general chemistry course remains as crowded with respect to the number of topics it covers as it was in the mid-1980s when a similar study was conducted (1). Nevertheless, some shifts in content emphases are noted. Introductory organic chemistry (hydrocarbons and functional groups) is covered in general chemistry courses and the companion laboratory by approximately 50% of respondents. About 60% of the introductory chemistry courses for science and engineering majors cover topics in environmental chemistry and about 45% have some coverage of chemistry of materials and polymers. On the other hand, topics pertaining to molecular orbitals, geometry of coordination compounds, the Born–Haber cycle, and applications of nuclear chemistry were judged inappropriate for the course by almost 20% of the survey respondents. These findings indicate some change of emphases away from physical chemical principles toward the more “relevant” chemistry of “every day living” and support the hypothesis that recent curriculum reform initiatives in this direction have begun to take effect. Nevertheless the data are consistent with the
Table 3. Methods Used To Evaluate Laboratory Performance in College General Chemistrya Method
No. Using Method
Judgment of instructor
106
Laboratory reports
161
Written examination
90 2 occasionally
Laboratory practical examination
44 2 occasionally
No response
1
a
Respondents were asked to check all that apply.
Table 4. Time Scheduled for College General Chemistry Laboratory Min/week
No. of Institutions
≤60
0
61–90
2
91–120
11
121–150
8
151–180
92
>180
46
No response
5
inference that overall, general chemistry courses for majors at leading colleges and universities have undergone relatively minor changes in content since the 1986 study was conducted. The time devoted to the chemistry laboratory remains significantly greater in colleges than in most AP chemistry courses. Recent editions of the AP chemistry course descriptions have included a “Guide for a Recommended Laboratory Program”, a feature expected to encourage secondary schools to increase their current laboratory offerings. The use of microscale laboratory in college chemistry courses for majors is minimal. For the vast majority of college chemistry courses surveyed, the plethora of topics covered in college general chemistry courses for majors may be the result of the implicit mission generally associated with the course: that it must provide background for various subsequent college courses in chemistry. The extent to which costs associated with change, for laboratory and computer facilities in particular, have contributed to retaining a status quo remains unknown. For AP chemistry, the results of this survey have been used to modify the course and examination so as to parallel more closely the equivalent general chemistry courses at leading colleges and universities (5). For chemistry curricula at postsecondary institutions, this study can serve as a baseline from which future reform in first year college chemistry courses can be measured. Literature Cited 1. Taft, H. L. J. Chem. Educ. 1990, 67, 241. 2. Advanced Placement Course Description for Chemistry; The College Board: New York, 1994. 3. Taft, H. L. In New Directions for General Chemistry; Lloyd, B., Ed.; Division of Chemical Education, 1994; pp 24–25. 4. Mullins, J. D. Teacher’s Guide to the Advanced Placement Course in Chemistry; The College Board: New York, 1994. 5. Advanced Placement Course Description for Chemistry; The College Board: New York, 1995.
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