Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 44

JURNAL & TRANSLET


The Effect Of The Worksheets On Students’ Achievement In Chemical Equilibrium

Nagihan YILDIRIM1, Sevil KURT2, Alipaşa AYAS3
1 Assist. Prof. Dr., Rize University, Faculty of Education, Rize-TURKEY
2 Dr. Res. Assist., Rize University, Faculty of Education, Rize-TURKEY
3 Prof. Dr., Bilkent University, Faculty of Education, Ankara-TURKEY
Received: 05.07.2010 Revised: 06.01.2011 Accepted: 25.01.2011
The original language of the article is English (v.8, n.3, September 2011, pp.44-58)

ABSTRACT
In the present study, it is aimed to determine effects of worksheets on students‟ achievement on the factors affecting equilibrium. The study was carried out with a quasi-experimental design. Data were collected through chemical equilibrium concept test, semi structured interviews and unstructured observations. The sample was 44 eleventh grade students enrolled in two classes from a secondary school in Trabzon in the fall term of the 2008-2009 academic years. Interview data were analysed descriptively. Data collected from chemical equilibrium concept test were analysed by using SPSS statistical programme. On the other hand data from unstructured observations were organized and then given directly. At the end of the study, it is found that experimental group students were more successful than the control group. As a result, a number of suggestions were made about development of worksheets in other difficult concepts of chemistry.
Keywords: Equilibrium; Effecting Factors of Equilibrium; Worksheets.
INTRODUCTION
Studies carried out in the field of chemistry reveal that one of the subjects where students have misconceptions is chemical equilibrium (Gussarsky & Gorodesky, 1990; Huddle & Pillay, 1996). These misconceptions and learning difficulties are on dynamic nature of equilibrium, equilibrium constant, heterogeneous equilibrium, gases equilibrium and Le Chatelier principle (Hackling & Garnett, 1985; Gorodesky & Hoz, 1985; Berguest & Heikkinen, 1990; Huddle & Pillay, 1996; Thomas & Schwenz, 1998; Voska & Heikkinen, 2000; Yıldırım, 2000; Chiu et al., 2002; Kousthana & Tsaparalis, 2002; Akkuş et al., 2003; Alkan & Benlikaya, 2004; Piquette & Heikkinen, 2005). Considering the fact that misconceptions affect subsequent learning in a negative way, it is quite important that students‟ scientific understanding of chemical equilibrium affects learning of many other subjects such as oxiditation-reduction, acid-base, reaction rate, and solubility equlibrium. Conceptual difficulties related to chemical equilibrium mainly derive from students‟ failure in
 Correspondence Author email: aksusevil_@hotmail.com © ISSN:1304-6020
TÜRK FEN EĞİTİMİ DERGİSİ
Yıl 8, Sayı 3, Eylül 2011
Journal of
TURKISH SCIENCE EDUCATION
Volume 8, Issue 3, September 2011
http://www.tused.org
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 45
imagining events that take place at the moment of equilibrium (Wheeler & Kass, 1978; Tyson, Treagust & Bucat, 1999; Kousathana & Tsaparlıs, 2002; Sepet, Yılmaz & Morgil, 2004). Students need to be able to imagine the equilibrium at macro, micro and symbolic levels in order to conceptually understand the topic. Another reason of students not to conceptualize the chemical equilibrium concept is the teaching method used in the classroom is based only on writing or lecturing. In parallel, students solves some numerical chemical equilibrium problems by using some formulas or procedures which were thaught in science classes (Berquest & Heikkinen, 1990; Tyson, Treagust & Bucat, 1999; Yıldırım, 2000). So when students were asked why they used these formulas or procedures they could not explain the reasons or sometimes they get the right results by coming up with wrong reasons (Kousathana & Tsaparlis, 2002; Weerawardhana, 2003; Quilez, 2004). To better understand the chemical equilibrium concepts students need to imagine the events that take place at the moment of equilibrium. It is important to develope spesific teaching-learning materials which take the students‟ misconceptions into consideration and make concrete examples of the events that take place at the moment of equilibrium. There have been numerous studies that investigated the effectiviness of different teaching methods and materials to overcome students misconcetions and learning difficulties of chemical equilibrium. In these studies, conceptual change approach, computer aided instruction, group discussion, constructivist teaching method, problem based learning, analogies and students‟ worksheets were generally investigated (Hameed et al, 1993; Niaz, 1995; Chiu et al., 2002; Akkuş et al., 2003; Weerawardhana, 2003; Sandberg & Bellamy, 2004; Coştu & Ünal, 2005; Harrison & Jong, 2005; Locaylocay et al., 2006; Sarıçayır, 2007). But among these there are limited studies which reports the effect of worksheets on students‟ achivement (Coştu & Ünal, 2005). However, worksheets are found useful and practical materials for conceptual understanding if they were effectively used in learning environments (Griffiths, Thomey, Cooke & Normore, 1988; Demircioğlu et al., 2004).
Worksheets are materials by which students are given transaction steps regarding what they are supposed to learn. Also, they include activities which give the students main responsibility in their own learning (Kurt & Akdeniz, 2002). Thus worksheets are known to help students gain scientific process skills such as setting up experimental mechanism, recording data, interpreting the data, and so on so that they can conceptualize the concepts in their minds. There are several studies showing that worksheets increase students‟ interest in the lesson and affect their success in a positive way (Saka & Akdeniz, 2001; Kurt, 2002; Coştu & Ünal, 2005; Özmen & Yıldırım, 2005; Kurt & Ayas, 2010).
In the present study, it is aimed to determine the effects of worksheets on students‟ achievement on the factors affecting equilibrium.
METHODOLOGY
This study was carried out with a quasi experimental design. Data collection instruments are Chemical Equilibrium Conceptual Test (CE-CT), semi-structured interviews and observations.
a- Sample
The study was carried out with 44 twelfth grade students in two different classes attending to a secondary school in Trabzon in the fall term of the 2008-2009 academic year. The sample was separated into experimental and control groups on a random basis. The factors affecting equilibrium (concentration, temperature and pressure) were taught by the same teacher in both groups. To decide that the students in the experimental and control groups were similar in terms of socio-economic and educational backgrounds, the points of
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 46
views of the teacher were taken. Also Mann Whitney U test results of pre test scores of the experimental and control groups showed that two groups were equivalent by means of prior-knowledge on chemical equilibrium.
b- Worksheets
The researchers developed three worksheets on factors that affect the equilibrium to be used in the experimental group. Worksheets were developed on the basis of a four step constructivist teaching strategy. Students‟ misconceptions and learning difficulties are also taken into consideration on chemical equilibrium. Before the implementation, the teacher was trained about what a worksheet is and how it is used in teaching. Also, upon the teacher‟s request, experiments on the worksheets were done by researchers and the teacher together before they used. The intervention consisted of six lessons of 45 minutes duration in the experimental group.
c- Procedure
The intervention involved the following steps:
Firstly, the students divided into six groups, (each contained four students) and the teacher gave brief information on how students should use the worksheets. Then the teacher handed the worksheets out to students. He asked the questions in first part of worksheets to explore students‟ prior knowledge and to engage them in the activity. In the following step, students were asked to perform the given directions in the second part of each of the worksheets and then discuss their ideas in their groups. In this section it was aimed to provide opportunities to students‟ own learning. In the next step, the groups presented their ideas to other groups and finally the teacher sum up the groups‟ ideas with scientific explanations. At the last part of the activity, the students were asked to answer the questions given at the end of the worksheets. In this part the aim was to help students to reinforce their new learning and transfer their new knowledge to other situations. A sample worksheet is attached in the appendix. No intervention was planned for the control group. They followed their regular way of teaching which was known as teacher centered. One of the researchers participated in each lesson and observed the interventions.
d- Instruments and data analysis
The CE-CT, comprised of 17 questions and its validity and reliability was predetermined, was applied as pre and post test to the both groups (Yıldırım, Bak & Ayas, 2007). The data collected from the CE-CT was analyzed by using SPSS software. Comparisons within the groups were realized by using Wilcoxon Signed Ranks Test, and comparisons between groups were made by using Mann Whitney U Test, and results of the analysis were given in tables. Because of number of students in each groups which was less than thirty, nonparametric tests were used (Kalaycı, 2008).
The semi-structured interviews were carried out with 6 students, 3 from each group. Four questions were asked to each student during the interviews. The interviews were tape-recorded and then transcribed verbatim. While experimental group participants in the interviewees were coded as A, B and C, those coming from the control group were coded as D, E and F. The data collected from the interviews were analysed descriptively. Students‟ Drawings and answers to the interview questions were given in tables.
On the other hand, one of the researchers who carried out observations in the two groups made notes during her observations. The data obtained from the observations were organized by the researchers and was directly used to support findings from the other instruments.
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 47
FINDINGS
a- Findings Obtained from CE-CT
Comparisons made within and between groups in terms of pre- and post-test scores of
the CE-CT applied in the experimental and control groups. Comparisons within the groups
were realized by using Wilcoxon Signed Ranks Test, and comparisons between groups were
made by using Mann Whitney U Test, and results of the analysis were given in tables. In
Table 1, Mann Whitney U Test results of pre test scores of the groups are given.
Table 1. Mann Whitney U Test Results of Pre Test Scores of the Experimental and Control Groups
Groups n X Mean Rank Sum of
Ranks
U p
Experimental 24 13,9167 20,08 482,00
182,00
Control 20 15,6500 25,40 508,00 0,170
An examination of the results given in Table 1 indicates that there is no significant
difference between pre-test scores of the control and experimental group (U=182,00; p>.05).
In Table 2, Wilcoxon Signed Ranks Test results of pre-test and post-test scores of the
experimental group are given.
Table 2. Wilcoxon Signed Ranks Test Results of Pre Test and Post Test Scores of the Experimental
Group
Post Test-Pre Test n Mean Rank Sum of Ranks z p
Negative ranks 0 0 0
Positive ranks 24 12,50 300 4.28* 0.00
Ties 0
*Based on negative ranks
The results given in Table 2 shows that there is a significant difference between preand
post-test scores obtained from the experimental group (z=4.28, p<.05). Considering the
sum of ranks of difference scores, this difference is in favor of the positive ranks and posttest.
In Table 3, Wilcoxon Signed Ranks Test results of pre- and post-test scores of the control
group are given.
Table 3. Wilcoxon Signed Ranks Test results of pre test and post test scores of the control group
Post Test-Pre Test n Mean Rank Sum of Ranks z p
Negative ranks 0 0 0
Positive ranks 20 10.50 210 3.92* 0.00
Ties 0
*Based on negative ranks
The results given in Table 3 shows that there is a significant difference between preand
post-test scores obtained from the control group (z=3.92, p<.05). Considering the sum of
ranks of difference scores, this difference is in favor of the positive ranks and post test.
In Table 4, Mann Whitney U Test results of post test scores of the experimental and
control groups are given.
Table 4. Mann Whitney U Test results of post test scores of the experimental and control groups
Groups n X Mean Rank Sum of
Ranks
U p
Experimental 24 102,8750 29,06 697,50 82,50 0,000
Control 20 82,6000 14,63 292,50
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 48
The results given in Table 4 indicates a significant difference between post-test scores
obtained from the control and experimental groups (U=82,50; p<.05). The difference is in
favor of the experimental group. Mean score of the control group is 102,875 while it is 82,60
in the experimental group.
b- Findings from Interviews
During interviews, the students were asked regarding HEAT + N2O4(g) 2NO2(g)
reaction to explain how the equilibrium and equilibrium constant is affected under following
circumstances in relation with the collision theory, Le Chatelier principle and equilibrium
constant law, and to draw time graphics of the concentration accordingly:
1. Adding some N2O4 gas to the medium at constant temperature and volume
2. Temperature is increased at constant volume
3. Volume is decreased at constant temperature
Finally, the students in the experimental group were asked for their opinion and
recommendations about the implementation. Students‟ responses are given in tables 5, 6, 7
and 8.
Table 5. Students’ responses regarding the first circumstance (some N2O4 gas is added to the medium
at constant temperature and volume)
S.C. Students‟ responses Students‟
drawings
A “N2O4 first increases, then decreases, the system shifts to the products, concentration
of the products will increase, concentration of the N2O4 will be higher than the first
concentration.‟ „Kd constant will not be affected, the equilibrium constant will not be
affected either, because they increase in the same proportion.”
B “Upon addition, N2O4 first increases then decreases, that of the products increases,
too. The products and inputs were at equilibrium already. As substance is added to the
inputs, it does not decrease below the first concentration.”
“Concentration does not affect the equilibrium constant, only temperature affects.”
C “First concentration of N2O4 increases, then decreases. Then it comes to the
equilibrium but it does not increase up to its former level. On the other hand, that of
NO2 increases and then comes to the equilibrium, and the equilibrium tends towards
the products. That of the both increases in comparison with their former
concentrations.‟„ Kd remains constant; it remained constant as concentration of both
increased in the same proportion.”
D “Upon addition of substances, the equilibrium will shift towards the other side to
maintain the equilibrium. It is a matter of action and reaction‟. But I can‟t draw it”
“Kd temperature affects but I am trying to remember concentration! Adding substances
does not change Kd. Or otherwise? Yes, yes. It does not affect the value of Kd.”
E “If affected by inputs, concentration of the products increases. Equilibrium constant
increases.”
No drawing
F “NO2 increases while N2O4 decreases”
“Equilibrium constant increases because the value of NO2 increases as well.”
S.C: student code
Table 5 shows that the students could answer accurately the question about changes in
the equilibrium and equilibrium constant upon addition of some N2O4 to the reaction.
However; student D and E in the control group could not draw the concentration-time graphic
and could not make detailed explanations, either.
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 49
Table 6. Students’ responses regarding the first circumstance (Temperature is increased at constant volume
S.C.
Students‟ responses
Students‟ drawings
A
“To the products side because it received heat, it causes the equilibrium to shift towards the products.‟
„Equilibrium constant products increased, inputs were decreased, equilibrium constant increased.‟
B
„Increase of heat increases concentration of the products and decreases concentration of inputs in endothermic reactions; so Kd increases‟
C
„N2O4 decreases, NO2 increases because increase of heat in endothermic reactions unbalances the equilibrium in favor of products.‟
„Kd increases because the equilibrium is unbalanced in favor of the products, concentration of the products increases while concentration of the inputs decreases.‟
D
„The equilibrium shifts towards the products because this is an endothermic reaction
„Numerical value of the Kd increases.‟
E
„Increased temperature results in reaction, products increase, inputs decrease.‟
F
„The equilibrium shifts towards products, concentration of the products increases while concentration of imputes decreases. „Equilibrium constant increases.‟
No drawing
S.C: student code
According to Table 6, the students in both groups could answer the questions about changes that take place in the reaction and equilibrium constant as a result of increased temperature. However student F in the control group could not draw the graphic of concentration-time.
Table 7. Students’ responses regarding the first circumstance (Volume is decreased at constant temperature)
S.C.
Students‟ responses
Students‟ drawings
A
“The equilibrium shifts towards inputs because decreased volume increases pressure. The side with higher number of moles is affected more. The system shifts towards the side with less number of moles to relieve this effect. Concentration of the inputs increases while concentration of the products decreases.”
“Equilibrium constant doesn‟t change because it changes with temperature only.”
B
“The equilibrium shifts towards inputs because decreased volume increases pressure according to the Le Chatelier principle. So equilibrium shifts towards inputs to relieve this.”
“Equilibrium constant changes with temperature only.”
C
“It shifts towards the side with more products, no, with higher number of moles. Since pressure increases, reaction becomes less in a bigger bowl while reaction becomes severer in a small bowl. N2O4 enters into more reaction and decreases while NO2 increases.”
„Kd remains constant because while one increases, the other increases and is fixed.‟
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 50
Table 7. Continued..
D
“Pressure increases. Thus, the side with higher number of moles will be affected more deeply. As a result, the equilibrium is unbalanced towards the inputs.‟
„Equilibrium constant is not affected by this.”
E
“Reaction arises in a way to relieve effects, concentration of products decreases while concentration of inputs increases”
“Equilibrium constant is affected by temperature only.”
F
“Equilibrium shifts towards inputs because pressure increases; it unbalances the equilibrium towards inputs.”
“Equilibrium constant decreases, it decreases because concentration of the inputs will increase.”
No drawing
S.C: student code
According to Table 7, students could mostly answer accurately the question about changes seen in the equilibrium and equilibrium constant as a result of changed volume in given reaction. However student F gave wrong answer for the question about equilibrium constant and could not provide a drawing.
Table 8. Comments of the Experimental Group Students about the Application Realized
S.C.
Students‟ comments
A
„It was good that experiment was realized before the subject was taught. So we wondered the result. Also it was good to carry out it with group mates. But it could have been even better if we had held the experiments individually. Still, it had positive effects. We could understand what was going on. It would not have been permanent if the teacher had taught verbally only.‟
B
„For me, it was funny and good. I was confused, and then came to the laboratory. Before, we used to say that equilibrium shifts towards left or right but I could not conceptualize it. Now I can see what happens as equilibrium of the system is unbalanced.‟
C
It was good. The experiments reinforced the subject, also color changes were good. It was very exciting for me.‟
S.C: student code
According to Table 8, mostly students found the application funny and exciting, and it proved to be effective in conceptualizing knowledge.
DISCUSSION
In the present study, it is aimed to determine effects of worksheets on students‟ achievement on chemical equilibrium. For this, CE-CT was applied as pre-test to all of the participants in the experimental and control groups before the topic taught on factors (concentration, temperature and pressure) affecting chemical equilibrium . Mann Whitney U test results (Table 1) showed no significant difference between pre-test scores of the groups (U= 182,00; p>.05). This reveals that students in the experimental and control groups had equivalent success levels regarding affecting factors of chemical equilibrium before the study. Wilcoxon Signed Ranks Test results indicated a significant difference between pre and post test scores in each group after application in each group (Table 2 and 3). This demonstrates that students‟ achievement on concept of chemical equilibrium improved in both control and experimental groups as a consequence of the teaching process. This is regarded to learning as
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 51
a consequence of teaching. Also, Mann Whitney U Test was applied to post test scores of the
groups if there is a significant difference between them. Mann Whitney U Test showed a
significant difference between the experimental and control groups in favor of the
experimental group. Mean score of the control group is 14,63 while it is 29,06 in the
experimental group (Table 4). This demonstrates that the worksheets proved more effective
than the traditional method in teaching the concepts related to chemical equilibrium. In
traditional teaching process, teachers usually lecture and students are passive learners. On the
other hand, in learning environments with worksheets, students actively participate in the
teaching process. In this process, students use materials-equipment, make observations, record
data, analyse data and draw conclusions. Such activities undertaken by students are important
for turning abstract knowledge into concrete knowledge. The experimental group participants
also stated during the interviews that the application proved to be effective for permanent
learning. Other studies carried out suggest that such activities help students understand the
abstract concepts such as chemical equilibrium and also the worksheets assist teaching of
difficult topics (Ayas, Akdeniz & Çepni, 1994; Çepni, Akdeniz & Ayas, 1995; Daunt, 1997;
Serin, 2002).
During interviews held with the experimental and control groups, the participants were
first asked to explain changes in equilibrium and equilibrium constant upon addition of some
N2O4 gas to the HEAT + N2O4(g) 2NO2(g) reaction at constant temperature and volume,
and then to draw the time graphic accordingly. Table 5 includes students‟ responses to this
question. It shows that the students in the experimental group could answer accurately to the
questions regarding changes in equilibrium and equilibrium constant. Students D and E in the
control group could not draw concentration-time graphic, and could not make detailed
explanations. This reveals that the students D and E could not figure out the increase of
concentration of the substance added into a system at balance. According to Wheeler and
Kass (1978), concentration-time graphics are quite effective in students‟ understanding what
to take place if effect is made on a balanced system. Besides, student E stated that equilibrium
constant increase if substance is added to the balanced system. One of the misconceptions
noted by Bergquest and Heikkinen (1990) in their study is that students think that equilibrium
constant changes upon changing of the inputs and product amount. During the interviews, the
experimental and control group participants could mostly draw accurately concentration-time
graphic with increased temperature in the reaction (Table 6). Student F in the control group
stated that chemical equilibrium shifts towards products but could not draw the graphic. In
addition, all of the students could answer accurately the question regarding change of the
value of Kd in relation with temperature. Table 7 shows that the participants could mainly
answer accurately the questions regarding equilibrium and equilibrium constant with change
of volume in the reaction given whereas student F gave wrong answer regarding equilibrium
constant and could not make drawing like under the other three questions. Moreover; student
F stated that value of the equilibrium constant changes in case of change of volume. Such a
misconception was also found out in other studies carried out by Yıldırım (2000) and Yıldırım
et al (2007).
The students in the experimental group mixed all materials given before reading
instructions on the worksheets and took various materials from cupboards in previous lessons.
It might be explained with insufficient participation of students in laboratory activities before.
Özmen and Yıldırım (2005) reached similar findings as well. In following lessons, students
were seen to be able to undertake the activities themselves and became more practical. During
interviews, student B said, in relation with the activity carried out, „I was confused, and then
came to the laboratory. Before, we used to say that equilibrium shifts towards left or right but
I could not conceptualize it. Now I can see what happens as equilibrium of the system is
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 52
unbalanced.‟ (Table 8). This quotation suggests that experiments under training activities on the worksheets drew students‟ attention, and overall application helped to conceptualize the concepts. Regarding chemistry classes, the researchers in the literature state that students cannot acquire permanent knowledge unless information is transferred on the basis of experiments (Ayas, Çepni, Johnson & Turgut, 1997). Students make observations, record data, draw conclusions from the data and thus take active role in the process while they carry out experiments in the laboratory (Temel, Oral & Avanoğlu, 2000; Üce, Sarıçayır & Demirkaynak, 2003). Demircioğlu, Demircioğlu and Ayas (2004) suggest that behaviors acquired when the students take active role are more permanent and significant than those acquired by audial or visual means only.
Student B in the experimental group stated during interviews that doing experiments on an individual basis would be better. During observations, mostly the same students undertook the transactions in the first class of application. Since students work on their own in traditional classroom environments, they could have had difficulties in group work. On the other hand, students made group work and acted as a group in the following lessons. It was seen that student-student and teacher-student interactions became more common in time as well. The students started asking questions in groups. Furthermore; the teacher guided students to think by means of asking questions. Studies carried out proved that the laboratory environment increased not only activities, assistance, taking responsibility, observation and trial and error within groups but also interest in the lesson and thus achievement in chemistry (Ayas et al., 1994; Üce & Şahin, 2001; Orbay et al., 2003; Üce, Sarıçayır & Demirkaynak, 2003; Özmen & Yıldırım, 2005).
CONCLUSIONS and RECOMMENDATIONS
This study was carried out to determine effects of worksheets on students‟ achievement on factors affecting chemical equilibrium. As a consequence, it was found out that worksheets increase students‟ achievement regarding factors affecting chemical equilibrium. In this sense, worksheets can be developed at conceptual basis for other chemistry topics that are difficult to understand. Besides, participants stated that they enjoyed the activity and the application was funny. Long-term studies on the basis of worksheets in various subjects can be used to find out their effectiveness in students‟ affective behavior.
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 53
REFERENCES
Akkuş, H., Kadayıfçı, H. & Atasoy, B. (2003). Effectiveness of instruction based on the constructivist approach on understanding chemical equilibrium concepts. Research in Science and Technological Education, 21(2), 209-227.
Alkan, M. & Benlikaya R. (2004). Kimyasal Reaksiyon ve Denge Kavramlarının Anlaşılması için Çarpışma Teorisi Gerekli mi?, VI. Ulusal Fen Bilimleri ve Matematik Eğitimi Kongresi, İstanbul, Eylül.
Ayas, A., Akdeniz, A. R. & Çepni, S. (1994). Fen bilimleri eğitiminde laboratuarın yeri ve önemi-1: Tarihsel bir bakış. Çağdaş Eğitim Dergisi, 204, 21-25.
Ayas, A., Çepni, S., Johnson, D. & Turgut, M.F. (1997). Kimya Öğretimi, Öğretmen Eğitimi Dizisi, YÖK/Dünya Bankası Milli Eğitimi Geliştirme Projesi Yayınları, Bilkent, Ankara.
Berguest, W. & Heikkinen, H. (1990). Student ideas regarding chemical equilibrium. Journal of Chemical Education, 67, 1000-1003.
Çepni, S., Akdeniz, A. R. & Ayas, A. (1995). Fen bilimleri eğitiminde laboratuarın yeri ve önemi (III): Ülkemizde laboratuar uygulamaları ve öneriler. Çağdaş Eğitim Dergisi, 206, 24–28.
Chiu, M., Chou, C. & Liu, C. (2002). Dynamic process of conceptual change: analysis of constructing mental models of chemical equilibrium. Journal of Research in Science Teaching, 39(6), 688-712.
Coştu, B. & Ünal, S. (2005). Le-Chatelier prensibinin çalışma yaprakları ile öğretimi. Yüzüncü Yıl Üniversitesi Elektronik Eğitim Fakültesi Dergisi, 1, 1.
Daunt, B. (1997). Öğreticinin El Kitabı, Çev: H. Kalkandelen, Ankara: Pegem Yayıncılık.
Demircioğlu, H., Demircioğlu, G. & Ayas, A. (2004). kavram yanılgılarının çalışma yapraklarıyla giderilmesine yönelik bir çalışma. Milli Eğitim Dergisi, 163.
Gorodetsky, M. & Hoz, R.(1985). Changes in the group cognitive structure of some chemical equilibrium concepts following a university course in general chemistry. Science Education, 69, 185–199.
Griffiths, A. K., Thomey, K., Cooke, B. & Normore, G.(1988). Remediation of student-spesific misconception relating to three science concepts. Journal of Research in Science Teaching, 25(9), 709-719.
Gussarsky, E. & Gorodetsky, M.(1990). On the concept „chemical equilibrium‟: the associative framework. Journal of Research in Science Teaching, 27, 197-204.
Hackling, M. W. & Garnett, P.J.(1985). Misconceptions of chemical equilibrium. European Journal of Science Education, 7, 205-214.
Hameed, H., Hackling, M.W. & Garnett, P.J.(1993). Facilitating conceptual change in chemical equilibrium using CAI strategy. International Journal of Science Education, 15(2), 221-230.
Harrison, A. G. & Jong, O.(2005). Exploring the use of multiple analogical models when teaching and learning chemical equilibrium. Journal of Research in Science Teaching, 42(10), 1135–1159.
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 54
Huddle, P.A. & Pillay, A. E. (1996). An in-depth study of misconceptions in stoichiometry and chemical equilibrium at South African University. Journal of Research in Science Teaching, 33, 65-77.
Kalaycı, 2008. SPSS Uygulamalı Çok Değişkenli İstatistik Teknikleri, Asil Yayın Dağıtım Ltd. Şti, 3. Baskı, Ankara.
Kousthana, M. & Tsaparlis, G. (2002). Students errors in solving numerical chemical-equilibrium problems. Chemistry Education: Research and Practice in Europe, 3(3), 5-17.
Kurt, S. & Ayas, A. (2010). Bir Öğretim Teknolojisi Olarak Çalışma Yapraklarının Kimyasal Reaksiyonların Hızı Konusunda Öğrenci Başarısına Etkisi, International Educational Technology Conference, İstanbul, Boğaziçi University.
Kurt, Ş. (2002). Fizik Öğretiminde Bütünleştirici Öğrenme Kuramına Uygun Çalışma Yapraklarının Geliştirilmesi, Yüksek Lisans Tezi, K.T.Ü. Fen Bilimleri Enstitüsü, Trabzon.
Kurt, Ş. & Akdeniz, A.R. (2002). Fizik Öğretiminde Enerji Konusunda Geliştirilen Çalışma Yapraklarının Uygulanması, V. Ulusal Fen Bilimleri ve Matematik Eğitimi Kongresi, Bildiriler Kitabı, Cilt I, (s:570-576), Ankara, ODTÜ.
Niaz, M. (1995). Relationship between student performance on conceptual and computational problems of chemical equilibrium. International Journal of Science Education, 17(3), 343-355.
Locaylocay, J., Berg, E. & Mango, M.(2006). Changes in college students‟ conceptions of chemical equilibrium. Research and the Quality of Science Education, 8, 459-470.
Orbay, M., Özdoğan, T., Öner,F., Kara, M. & Gümüş, S. (2003). "Fen bilgisi laboratuar uygulamaları I-II" dersinde karşılaşılan güçlükler ve çözüm önerileri. Milli Eğitim Dergisi, 157.
Özmen, H. & Yıldırım, N. (2005). Çalışma yapraklarının öğrenci başarısı üzerine etkisi: Asitler ve bazlar örneği. Türk Fen Eğitimi Dergisi, 2(2), 125-142.
Piquette, J. S. & Heikkinen, H. W.(2005). Strategies reported used by instructors to address student alternate conceptions in chemical equilibrium. Journal of Research in Science Teaching, 42, 1112-1134.
Quílez, J. (2004). Changes in concentration and in partial pressure in chemical equilibria: Students and Teachers‟ misunderstandings. Chemistry Education: Research and Practice, 5(3), 281–300.
Saka, A., & Akdeniz, A.R. (2001). Biyoloji Öğretmenlerine Çalışma yaprağı Geliştirme ve Kullanma Becerileri Kazandırmak İçin Bir Yaklaşım, Yeni Bin Yılın Başında Türkiye‟de Fen Bilimleri Sempozyumu, İstanbul, Maltepe University.
Sandberg, M. & Bellamy, M. (2004). A Web-based applet to teach Le Chatelier's Principle. Journal of Science Education, 5(1), 41.
Sarıçayır, H. (2007). Kimya Eğitiminde Kimyasal Tepkimelerde Denge Konusunun Bilgisayar Destekli ve Laboratuar Temelli Öğretiminin Öğrencilerin Kimya Başarılarına ve Hatırlama Düzeylerine ve Tutumlarına Etkisi, Doktora Tezi, Marmara Üniversitesi Eğitim Bilimleri Enstitüsü, İstanbul.
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 55
Sepet, A., Yılmaz, A. & Morgil, İ. (2004). Lise ikinci sınıf öğrencilerinin Kimyasal Denge konusundaki kavramları anlama seviyeleri ve kavram yanılgıları. Hacettepe Üniversitesi Eğitim Fakültesi Dergisi, 26, 148-154.
Serin, G. (2002). Fen Eğitiminde Laboratuar, Fen Bilimleri Eğitimi Sempozyumu, İstanbul, Maltepe University, 403-406.
Temel, H., Oral, B & Avanoğlu, Y. (2000). Kimya öğrencilerinin deneye yönelik tutumları ile titrimetri deneylerini planlama ve uygulamaya ilişkin bilgi ve becerileri arasındaki ilişkinin değerlendirilmesi. Çağdaş Eğitim Dergisi, 264, 32-38.
Thomas, P.L. & Schwenz, R.W. (1998). College physical chemistry students‟ conceptions of equilibrium and fundamental thermodynamic. Journal of Research in Science Teaching, 35, 1151-1160.
Tyson, L., Treagust, D. F. & Bucat.,R.B. (1999). The complexity of teaching and learning chemical equilibrium. Journal of Chemical Education, 76 (4), 554-558.
Üce, M, & Şahin, M. (2001). Marmara Üniversitesi Atatürk Eğitim Fakültesi Kimya Eğitimi Anabilim Dalı Öğrencilerinin Kullandıkları Laboratuarlar Hakkındaki Görüşleri, Fen Bilimleri Eğitimi Sempozyumu, İstanbul, Maltepe University, 398–402.
Üce, M., Sarıçayır, H. & Demirkaynak, N. (2003). Ortaöğretim kimya eğitiminde asitler ve bazlar konusunun öğretiminde klasik ve deneysel yöntemlerin başarıya ve kimya tutumuna etkisinin karşılaştırılması. M.Ü. Atatürk Eğitim Bilimleri Dergisi, 18, 93-104.
Voska, K.W. & Heikkinen, H.W. (2000). Identification and analysis of student conceptions used to solve chemical equilibrium problems. Journal of Research in Science Teaching, 37(2), 160-176.
Weerawardhana, A. (2003). Developing Conceptual Understanding of Chemical Equilibrium Through the Use of Computer-based Visualization Software, 9th International Conference on Sri Lanka Studies, 28-30 November, Matar, Sri Lanka.
Wheeler, A.E. & Kass, H. (1978). Student misconceptions in chemical equilibrium. Science Education, 62, 223–232.
Yıldırım, A. (2000). Kimyasal Denge Konusundaki Kavramların Lise II Öğrencilerince Anlaşılma Düzeyi ve Karşılaşılan Yanılgılar, Yüksek Lisans Tezi, K.T.Ü. Fen Bilimleri Enstitüsü, Trabzon.
Yıldırım, N., Bak, Z. & Ayas, A. (2007). Kimyasal Denge Konusundaki Kavram Yanılgılarına Yönelik Gelişimsel Bir Çalışma, 16. Ulusal Eğitim Bilimleri Kongresi, Tokat, Gazi Osman Paşa Universitesi.
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 56
Appendix: A Sample Worksheet
Effect of Temperature on Chemical Equilibrium
…………………………………………………………………………………………………………………………………………………………………………………………………… Let’s observe, what’s happening when temperature of system is increased!
Equipments : 250 ml hot water, 250 ml iced water, 2 g Cu(NO3)2, 2g NaCI, 4 test tube, 2 beaker
1. Solve Cu(NO3)2 and NaCl salts into a test tube with pure water. Put the solution into two separate test tubes. The reaction equation is below.
CuCl4(aq) + H2O(l) Cu(H2O)42+ (aq) + 4Cl-(aq) + HEAT
2. Put the first test tube in a beaker with half full ice-water and observe color change. Record your observation results. What’s the reason of change, explain why?.
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
3. Put the second test tube in a beaker with half full hot water and observe color change. Record your observation results. What’s the reason of change, explain why?.
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
4. Put the first test tube in a beaker with hot water and put the second test tube in a beaker with ice-water and observe color change. Record your observation results. What’s the reason of change, explain why?.
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
5. According your observations and Le Chatelier principle, explain that how the equilibrium situation will affected when temperature is decreased in exothermic reactions.
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
The reaction below is equilibrium situation in constant temperature and volume. How the equilibrium situation is effected when temperature of system is increased?
Co(H2O)6(aq)+4CI-+HEAT CoCI2(aq) + 6H2O(l)
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 57
Answer the questions below with your group mates.
6. Which changes will occur in forward and reverse reaction rate compared to their initial states when the temperature of equilibrium system is increased? Explain your answer using collision theory and kinetic theory.
…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
7. How the equilibrium situation and equilibrium constant are affected when temperature of system is increased in exothermic reactions? Explain your answer with your reasons.
…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
8. How the concentrations of reactants and products are change compared to their initial states when temperature of system is increased in endothermic reactions? Explain your answer with its reasons.
…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
9. 2 A2(g) + B2(g) 2 A2B(g) ΔH < 0 when this reaction is on equilibrium situation in t1 time and in constant volume;
How the the concentrations of A2, A2B and B2 change when the temperature of system is increased until occurrence of a new equilibrium situation? Write the reasons of your answer on the blanks. ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
Concentration (Mole/L)
Time (sn)
Yıldırım, Kurt & Ayas / TUSED / 8(3) 2011 58
......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
How the concentrations of A2, A2B and B2 change when the temperature of system is decreased until occurrence of a new equilibrium situation? Write the reasons of your answer on the blanks.
Concentration (Mole/L)
Time (sn)


TRANSLET JURNAL

The Effect of the worksheets on students’ achievement in chemical equilibrium

(pengaruh lembar kerja pada pencapaian siswa dalam keseimbangan kimia)

Abstrak

Dalam pelajaran ini, bertujuan untuk menentukan pengaruh lembar kerja bagi pencapaian siswa pada faktor-faktor yang mempengaruhi keseimbangan. Pelajaran ini dilaksanakan dengan bentuk penelitian yang tidak benar. Data dikumpulkan berdasarkan tes konsep keseimbangan kimia, wawancara yang tersusun sebagian dan observasi yang tidak tersusun. Sampel pada 44 siswa tingkat 11 yang diikuti 2 kelas dari Sekolah menengah di trabzon tahun ajaran 2008-2009. Data wawancara dianalisa dengan deskriptif. Data dikumpulkan dari tes konsep keseimbangan kimia yang dianalisa menggunakan program statistik SPSS. Disisi lain, data dari observasi yang tidak tersusun diatur dan disampaikan secara langsung.  Akhir pembelajaran, ditemukan bahwa siswa kelompok percobaan lebih berhasil daripada kelompok kontrol. Sebagai hasilnya, banyak saran dibuat tentang perkembangan lembar kerja konsep kimia sulit yang lain.

Kata kunci: keseimbangan, pengaruh faktor keseimbangan, lembar kerja

Pendahuluan

Pembelajaran dilaksanakan dalam bidang kimia yang mengungkapkan bahwa salah satu subjek dimana siswa memiliki kesalah pahaman adalah adalah keseimbangan kimia (Gussarsky & Gorodesky, 1990; Huddle & Pillay, 1996). kesalahpahaman ini dan kesulitan belajar adalah atas dasar keseimbangan dinamis, keseimbangan konstan, keseimbangan yang beraneka ragam, keseimbangan gas, dan Le Chatelier utama

 (Hackling & Garnett, 1985; Gorodesky & Hoz, 1985; Berguest & Heikkinen, 1990; Huddle & Pillay, 1996; Thomas & Schwenz, 1998; Voska & Heikkinen, 2000; Yıldırım, 2000; Chiu et al., 2002; Kousthana & Tsaparalis, 2002; Akkuş et al., 2003; Alkan & Benlikaya, 2004; Piquette & Heikkinen, 2005).  mengingat fakta bahwa kesalah pahaman mempengaruhi pelajaran berikutnya dalam cara yang negatif, sangat penting bahwa pemahaman ilmiah siswa pada keseimbangan kimiamempengaruhi pelajaran banyak subjek lain seperti oksidasi reduksi, asam dasar,  reaksi dasar, dan keseimbangan daya larutan. Kesulitan mengerti dihubungkan pada keseimbangan kimia terutama berasal dari kegagalan siswa membayangkan peristiwa saat terjadinya  keseimbangan. (Wheeler & Kass, 1978; Tyson, Treagust & Bucat, 1999; Kousathana & Tsaparlıs, 2002; Sepet, Yılmaz & Morgil, 2004). siswa perlu bisa membayangkan keseimbangan makro, mikro dan tingkat simbolik untuk memahami dengan pengertian topik. Alasan lain siswa tidak mengerti konsep keseimbangan kimia adalah metode pengajaran yang digunakan didalam kelas hanya berdasarkan pada tulisan atau ceramah.  Sama, siswa menyelesaikan masalah jumlah keseimbangan kimia menggunakan beberapa rumus atau prosedur yang diajarkan dalam kelas sains (Berquest & Heikkinen, 1990; Tyson, Treagust & Bucat, 1999; Yıldırım, 2000).. jadi ketika siswa bertanya kenapa mereka menggunakan rumus atau prosedur ini, mereka tidak bisa menjelaskan alasannya atau terkadang mereka mendapatkan hasil yang benar tapi memberikan alasan yang salah (Kousathana & Tsaparlis, 2002; Weerawardhana, 2003; Quilez, 2004). agar memahami lebih baik konsep keseimbangan  kimia, siswa perlu membayangkan peristiwa yang terjadi pada saat keseimbangan. Sangat penting untuk mengembangkan materi belajar mengajar yang spesifik yang mengambil kesalah pahaman siswa menjadi pertimbangan dan membuat contoh konkret peristiwa yang terjadi pada saat equilibrium. Ada banyak pembelajaran yang meneliti keefektifan dari perbedaan metode pengajaran dan materi untuk mengatasi kesalah pahaman siswa dan mempelajari kesulitan dari keseimbangan kimia. Dalam pembelajaran ini, pengertian mendekati perubahan, instruksi bantuan komputer, diskusi kelompok, membangun metode pengajaran, belajar berdasarkan masalah, analogi dan lembar kerja siswa umumnya diteliti. (Hameed et al, 1993; Niaz, 1995; Chiu et al., 2002; Akkuş et al., 2003; Weerawardhana, 2003; Sandberg & Bellamy, 2004; Coştu & Ünal, 2005; Harrison & Jong, 2005; Locaylocay et al., 2006; Sarıçayır, 2007). tapi diantara ini ada pembelajaran terbatas yang melaporkan pengaruh lembar kerja pada pencapaian siswa. (Coştu & Ünal, 2005). bagaimanapun, lembar kerja berguna dan alat praktis untuk memahami pengertian jika mereka dengan efektif digunakan dalam lingkungan belajar (Griffiths, Thomey, Cooke & Normore, 1988; Demircioğlu et al., 2004).

 lembar kerja adalah alat dimana siswa diberikan langkah-langkah transaksi mengenai apa yang harus mereka pelajari. Juga, lembar kerja ini termasuk kegiatan yang memberikan siswa tanggung jawab utama dalam pelajaran mereka sendiri (Kurt & Akdeniz, 2002). Demikian, lembar kerja dikenal untuk membantu siswa memperoleh keterampilan proses ilmiah seperti mengadakan mekanisme percobaan, merekam data, menafsirkan data, dan lain-lain. Jadi mereka bisa mengerti konsep dalam pikiran mereka. Ada beberapa pembelajaran yang menunjukkan bahwa lembar kerja menambah minat siswa dalam pelajaran dan memperoleh kesuksesan mereka dalam cara yang positif (Saka & Akdeniz, 2001; Kurt, 2002; Coştu & Ünal, 2005; Özmen & Yıldırım, 2005; Kurt & Ayas, 2010).

Dalam pengajaran saat ini, hal ini ditujukan untuk menentukan pengaruh lembar kerja pada pencapaian siswa atas faktor yang mempengaruhi keseimbangan.

Metodologi

Pembelajaran ini telah dilaksanakan dengan bentuk percobaan yang  tidak benar. Alat pengumpulan data adalah  tes konseptual keseimbangan kimia (CE-CT). Sebagian wawancara yang tersusun dan observasi.

1. Sampel

Pembelajaran ini dilaksanakan dengan 44 siswa tingkat 12 dalam 2 kelas yang berbeda disertai pada sekolah menengah di Trabzon tahun pelajaran 2008-2009. Sampel dipisahkan dalam kelompok percobaan dan kontrol pada basis acak. Fakto- faktor yang mempengaruhi keseimbangan( konsentrasi, temperatur dan tekanan)diajarkan oleh guru yang sama di kedua kelompok. Untuk memutuskan bahwa siswa di kelompok kontrol dan percobaan sama dalam ketentuan ekonomi sosial dan latar belakang pendidikan, pendapat guru diambil. Juga hasil tes Mann Whitney U dari nilai pre teskelompok kontrol dan percobaan menunjukkan bahwa 2 kelompok  sama dengan memakai pengetahuan sebelumnya pada keseimbangan kimia.   

2. Lembar kerja

Para peneliti mengembangkan tiga lembarkerja atas faktor-faktor yang mempengaruhi keseimbangan yang digunakan dalam kelompok percobaan. Lembar kerja dikembangkan pada basis empat langkah strategi pengajaran konstruktivis.kesalah pahaman siswa dan kesulitan belajar juga diambil sebagai pertimbangan  pada keseimbangan kimia. Sebelum iplementasi, guru dilatih tentang apa itu lembar kerja dan bagaimana kegunaannya dalam pengajaran. Juga, atas permintaan guru, percobaan pada lembar kerja telah dilakukan oleh peneliti dan guru bersama-sama sebelum mereka menggunakannya. Intervensi terdiri dari enam pelajaran yang berdurasi 45 menit dalam kelompok percobaan.

3. Prosedur

Intervensi melibatkan langkah-langkah berikut:

Yang pertama, siswa dibagi menjadi 6 kelompok (setiap kelompok terdiri dari 4 siswa) dan guru memberikan informasi laporan singkat bagaimana siswa harus menggunakan lembar kerja. Kemudian guru memberikan lembar kerja kepada siswa. Dia menanyakan pertanyaan dibagian pertama untuk menyelidiki pengetahuan terdulu siswa dan untuk mengajak mereka dalam kegiatan. Langkah berikutnya, siswa diminta untuk menampilkan petunjuk yang telah diberikan pada bagian kedua setiap lembar kerja dan kemudian mendiskusikan ide-ide mereka dalam kelompok mereka. Dibagian ini bertujuan untuk memberikan kesempatan pada siswa belajar sendiri. Pada langkah selanjutnya, kelompok itu mempresentasikan ide-ide mereka pada kelompok lain dan terakhir guru menyimpulkan ide-ide kelompok itu dengan penjelasan ilmiah. Pada bagian terakhir kegiatan, siswa diminta untuk menjawab pertanyaan yang diberikan pada akhir lembar kerja. Pada bagian ini tujuannya adalah untuk membantu siswa menguatkan pelajaran baru mereka dan memindahkan pengetahuan baru mereka pada situasi yang lain. Sampel lembar kerja dilampirkan pada lampiran. Tidak ada intervensi yang direncanakan untuk kelompok kontrol. Mereka mengikuti cara pengajaran yang tetap yang dikenal dengan pusat guru. Salah satu peneliti berpartisipasi dalam pelajaran dan mengobservasi intervensi.    

4. Alat dan analisis data

CE- CT  terdiri dari 17 pertanyaan yang kebenaran dan kenyataannya ditetapkan sebelumnya, diterapkan sebagai pre dan post tes untuk kedua kelompok (Yildirim......dst). Data dikumpulkan dari CE- CT yang dianalisa menggunakan perangkat lunak SPSS. Dibandingkan dengan kelompok yang dicapai menggunakan tes Wilcoxon signed ranks dan perbandingan antar kelompok dibuat menggunakan tes Mann Whitney U, dan hasil analisis diberikan dalam bentuk tabel. Karena jumlah siswa tiap kelompok kurang dari tiga puluh, tes nonparametrik diperlukan (Kalayei 2008).

Wawancara yang tersusun sebagian dilaksanakan pada 6 siswa, 3 orang dari tiap kelompok. 4 pertanyaan ditanyakan pada tiap siswa selama wawancara. Wawancara direkam dan kemudian ditulis kata per kata. Sementara peserta kelompok percobaan dalam wawancara diberi kode A, B, dan C, lalu yang berasal dari kelompok kontrol diberi kode D, E dan F. Data dikumpulkan dari wawancara yang dianalisa dengan deskriptif. Gambar dan jawaban siswa pada pertanyaan- pertanyaan wawancara disampaikan dalam tabel.  

Disisi lain, salah satu peneliti yang melaksanakan observasi dalam dua kelompok membuat catatan selama observasinya. Data dihasilkan dari observasi yang diatur oleh peneliti dan langsung digunakan untuk membantu penemuan dari alat lain.

Temuan / kesimpulan

1. Temuan yang dihasilkan dari CE-CT

Perbandingan dibuat diantara kelompok dalam ketentuan dari nilai pre dan post tes CE-CT yang diterapkan dalam kelompok percobaan dan kontrol. Perbandingan dalam kelompok didapat dengan menggunakan tes Wilcoxon Signed Ranks, dan perbandingan antar kelompok dibuat menggunakan tes Mann Whitney U dan hasil analisis disampaikan dalam tabel. Dalam tabel 1, hasil tes Mann Whitney U dari nilai pre test kelompok disajikan.

Tabel 1. Hasil tes Mann Whitney U dari nilai pre test kelompok percobaan dan kontrol

Kelompok              n            X                   pangkat rata-rata      jumlah pangkat   dari    U         p

Percobaan           24        dst Kontrol

Ujian dari hasil yangdisajikan dalam tabel 1 menunjukkan bahwa tidak ada perbedaan signifikan antara hasil pre test dari kelompok kontrol dan percobaan (U= 182,00;p>05).

Dalam tabel 2, hasil tes Wilcoxon Signed Ranks dari nilai pre test dan post test kelompok percobaan disajikan 

Tabel 2. Hasil tes Wilcoxon Signed Ranks dari nilai pre test dan post test kelompok percobaan

Post test- Pre test                       n           pangkat rata-rata         jumlah pangkat      z            p

Pangkat negatif                            0                   0                                         0            Pangkat positif                             24             dst Seri

*Berdasarkan pangkat negatif

Hasil yang disajikan dalam tabel 2 menunjukkan bahwa ada perbedaan signifikan antara nilai pre test dan post test yang dihasilkan dari kelompok percobaan (z=4.28, p< 05). Mengingat perbedaan nilai dari jumlah pangkat, perbedaan ini untuk pangkat positif dan post test. Dalam tabel 3, hasil tes Wilcoxon Signed Ranks dari hasil pre dan post test kelompok kontrol disajikan.

Tabel 3. Hasil tes Wilcoxon Signed Ranks dari nilai pre test dan post test kelompok kontrol

Post test- pre test             n           pangkat rata-rata          jumlah pangkat       z               p

Pangkat negatif                0                        0                                      0 Pangkat positif                 20                     10.50                               210                4.28*      0.00 Seri                                      0

Berdasarkan pangkat negatif

Hasil yang disampaikan dalam tabel 3 menunjukkan bahwa ada perbedaan signifikan antara nilai pre test dan post test yang dihasilkan dari kelompok kontrol (z=3.92, p<05). Mengingat perbedaan nilai jumlah pangkat, perbedaan ini untuk pangkat positif dan post test.

Dalam tabel 4, hasil tes Mann Whitney U dari nilai post test kelompok percobaan dan kontrol  disajikan.

Tabel 4. Hasil tes Mann Whitney U dari nilai post test kelompok percobaan dan kontrol

Kelompok                      n            X                    pangkat rata-rata     jumlah pangkat    of      U         p

Percobaan                    24         102, 8750    dst Kontrol                          20          82,6000

Hasil yang disampaikan dalam  tabel 4 menunjukkan perbedaan signifikan antara hasil post-test yang dihasilkan dari kelompok percobaan dan kontrol (U= 82,50; p<05). Perbedaan ini untuk kelompok percobaan. Nilai rata-rata kelompok kontrol adalah 102,875 sementara nilai rata-rata kelompok percobaan adalah 82,60.

2. Temuan dari wawancara

Selama wawancara, siswa ditanya mengenai reaksi HEAT + N2O4(g)       2NO2(g) untuk menjelaskan bagaimana keseimbangan dan keseimbangan konstan dipengaruhi oleh keadaan berikut dalam hubungan teori yang bertabrakan, prinsip Le Chatelier dan hukum keseimbangan konstan,  dan untuk menggambar konsentrasi grafik waktu sesuai dengan:

1. Menambahkan beberapa gas N2O4 pada temperatur dan volume konstan sedang.
2. Temperatur meningkat pada volume konstan
3. Volume menurun pada temperatur konstan

Terakhir,siswa dikelompok percobaan ditanya pendapat dan rekomendasi mereka tentang implementasinya.respon siswa disajikan dalam tabel 5,6,7 dan 8.

Tabel 5. Respon siswa mengenai keadaan pertama (beberapa gas N2O4 ditambahkan pada temperatur dan volume konstan sedang)

S.C       respon siswa                                                                                                                  gambar siswa

A         “N2O4 pertama bertambah, kemudian berkurang, sistem pindah pada             produk, konsentrasi produk akan bertambah, konsentrasi N2O4 akan menjadi             lebih tinggi daripada konsentrasi pertama.’ ‘ Kd konstan tidak akan berpengaruh,             keseimbangan konstan tidak akan berpengaruh juga, karena mereka bertambah             dalam proporsi yang sama.”

B         “Atas tambahan, N2O4 pertama bertambah, kemudian berkurang, yang mana            Produk bertambah juga. Produk dan input sudah seimbang. Zat itu ditambahkan            pada input, zat itu tidak berkurang dibawah konsentrasi pertama.”            “ konsentrasi tidak mempengaruhi keseimbangan konstan, hanya pengaruh            temperatur”

C         “konsentrasi pertama dari N2O4 bertambah, kemudian berkurang. Kemudian            konsentrasi itu menjadi seimbang tapi tidak bertambah menjadi tingkat            terdahulu. Disisi lain, NO2 bertambah kemudian menjadi keseimbangan, dan            keseimbangan tertuju pada produk. Oleh karena itu keduanya bertambah            dalam perbandingan dengan konsentrasi terdahulu mereka.’ ‘ Kd tetap konstan.            Kd tetap konstan sebagai konsentrasi keduanya ditambahkan dalam proporsi            yang sama.”

D         “ atas tambahan zat, keseimbangan akan pindah pada sisi lain untuk             mempertahankan keseimbangan.  Itu adalah perkiraan aksi dan reaksi.’             Tapi saya tidak bisa menggambarkannya” “temperatur Kd berpengaruh             tapi saya berusaha untuk ingat konsentrasi! Tambahan zat tidak merubah Kd.             Atau sebaliknya? Ya,ya. Itu tidak berpengaru pada nilai Kd.”

E          “jika dipengaruhi oleh input, konsentrasi produk bertambah. Keseimbangan   tidak ada             konstan bertambah                                                                                                           gambar

F          “ NO2 bertambah sementara N2O4 berkurang”              Keseimbangan konstan bertambah karena nilai NO2 bertambah dengan baik

S.C : kode siswa    

  

    Tabel 5 menunjukkan bisa menjawab dengan akurat pertanyaan tentang perubahan keseimbangan dan keseimbangan konstan atas tambahan beberapa N2O4 pada reaksi. Bagaimanapun juga, siswa D dan E dalam kelompok kontrol tidak bisa menggambar grafik konsentrasi waktu dan juga tidak bisa membuat penjelasan detil.

 Tabel 6. Respon siswa mengenai keadaan pertama (temperatur ditingkatkan pada volume konstan)

S.C       respon siswa                                                                                                               gambar siswa

A        “ pada segi produk karena itu mendapat tekanan, itu disebabkan             keseimbangan pindah pada produk.”             ‘produk keseimbangan konstan meningkat, input menurun, keseimbangan              Konstan meningkat.’

B         ‘peningkatan tekanan menambah konsentrasi produk dan mengurangi             konsentrasi input dalam reaksi endotermik; jadi Kd meningkat’

C         N2O4 menurun, NO2 meningkat karena peningkatan tekanan dalam reaksi             endotermik tidak seimbang untuk produk keseimbangan.’             ‘ Kd meningkat karena keseimbangan tidak seimbang untuk produk,             Konsentrasi produk meningkat sementara konsentrasi input menurun

D        ‘ Keseimbangan pindah pada produk karena ini adalah sebuah reaksi            endotermik  ‘ nilai urutan angka dari Kd meningkat.’

E        ‘ Hasil peningkatan temperatur dalam reaksi, produk meningkat, input             Menurun

F         ‘keseimbangan pindah pada produk, konsentrasi produk meningkat                 tidak ada             Sementara konsentrasi input menurun. ‘keseimbangan konstan meningkat’     gambar

S.C : kode siswa

Menurut  tabel 6, siswa di kedua kelompok bisa menjawab pertanyaantentang perubahan yang terjadi dalam reaksi dan keseimbangan konstan sebagai hasil dari peningkatan temperatur. Bagaimanapun juga, siswa F dikelompok kontrol tidak bisa menggambar grafik konsentrasi waktu.

Tabel 7.   Respon siswa mengenai keadaan pertama (volume meningkat pada temperatur konstan)

S.C      respon siswa                                                                                                               gambar siswa

A         “ keseimbangan pindah pada input karena penurunan volume             meningkatkan tekanan. Sisi dengan jumlah moles  lebih tinggi dipengaruhi             lebih. Sistem pindah pada sisi dengan jumlah moles sedikit untuk             mengurangi efek ini. Konsentrasi input meningkat sementara konsentrasi             produk menurun.”             “keseimbangan konstan tidak berubah karena keseimbangan itu berubah              hanya dengan temperatur.”

B          “keseimbangan pindah pada input karena penurunan volume              meningkatkan tekanan menurut prinsip Le Chatelier. Jadi keseimbangan              pindah pada input untuk mengurangi ini.”                 “keseimbangan konstan berubah hanya dengan temperatur.”

C           “itu pindah pada sisi dengan lebih banyak produk, tidak, dengan              jumlah moles lebih tinggi.  sejak tekanan meningkat, reaksi berkurang              dalam mangkok lebih besar sementara reaksi menjadi hebat didalam              mangkok kecil. N2O4 masuk kedalam reaksi lebih dan menurun sementara              NO2 meningkat.”              ‘ Kd tetap konstan karena sementara salah satu meningkat, yang lain               meningkat dan pasti.’

D          “Tekanan meningkat. Demikian, sisi dengan jumlah moles lebih tinggi              akan dipengaruhi lebih dalam lagi. Sebagai hasilnya, keseimbangan itu              tidak seimbang pada input.’              ‘ keseimbangan konstan tidak dipengaruhi oleh ini.”

E           “ reaksi timbul dalam suatu cara mengurangi efek, konsentrasi produk              menurun sementara konsentrasi input meningkat”              “Keseimbangan konstan hanya dipengaruhi oleh temperatur.”

F           “ keseimbangan pindah pada input karena tekanan meningkat, itu                tidak seimbang dengan keseimbangan pada input.”               “keseimbangan konstan menurun, penurunan itu karena konsentrasi input                akan meningkat

S.C : kode siswa

Menurut tabel 7, siswa kebanyakan bisa menjawab dengan akurat pertanyaan tentang perubahan yang terlihat pada keseimbangan dan keseimbangan konstan sebagai hasil perubahan volume dalam memberikan reaksi. Bagaimanapun, siswa F memberikan jawaban yang salah untuk pertanyaan tentang keseimbangan konstan dan tidak bisa menyediakan gambar.

Tabel 8. Komentar siswa kelompok percobaan tentang aplikasi yang didapat

S.C          komentar siswa

A          “ hal bagus bahwa percobaan didapat sebelum mata  pelajaran diajarkan. Jadi, kami berpikir tentang hasilnya. Juga bagus untuk mengerjakannya dengan teman sekelompok. Tapi itu bahkan bisa lebih baik jika kami mengadakan percobaan secara perorangan. Tetap, hal itu memiliki efek positif. Kami bisa mengetahui apa yang sedang terjadi. Hal itu tidak akan tetap jika guru hanya mengajar secara lisan.”

B           “bagiku, itu lucu dan bagus. Aku merasa bingung, kemudian aku datang ke laboratorium.     Sebelumnya, kami biasanya mengatakan bahwa keseimbangan pindah ke kiri atau kanan tapi aku tidak mengerti. Sekarang aku bisa tahu apa yang terjadi saat keseimbangan sistem tidak seimbang.’

C              bagus. Percobaan itu memperkuat mata pelajaran, juga perubahan warna menjadi bagus, itu mengasyikkan untukku.’

 S.C : kode siswa

Menurut tabel 8, kebanyakan siswa menemukan aplikasi yang lucu dan mengasyikkan. Dan itu ternyata efektif dalam memahami pengetahuan.

 Diskusi

Dalam pembelajaran saat ini, tujuannya adalah untuk menentukanpengaruh lembar kerja pada pencapaian siswa atas keseimbangan kimia. Untuk ini, CE-CT diterapkan sebagai pre-test pada semua peserta dalam kelompok kontrol dan percobaan sebelum topik dipelajari tentang fakto-faktor (konsentrasi, temperatur dan tekanan) merubah keseimbangan kimia. Hasil tes Mann Whitney U (tabel 1) menunjukkan tidak ada perbedaan signifikan antara nilai pre-test kelompok (U=182,00; p>05). Ini mengungkapkan bahwa siswa dalam kelompok kontrol dan percobaan mempunyai tingkat keberhasilan yang sama mengenai faktor-faktor yng mempengaruhi keseimbangan kimia sebelum belajar. Hasil tes Wilcoxon Signed Ranks menunjukkan perbedaan signifikan antara nilai pre dan post test tiap kelompok setelah aplikasi tiap kelompok (tabel 2 dan 3). Ini membuktikan bahwa pencapaian siswa terhadap konsep keseimbangan kimia meningkat dalam kedua kelompok kontrol dan percobaan sebagai konsekuensi dari proses pembelajaran. Ini dianggap belajar sebagai konsekuensi mengajar. Juga, tes Mann Whitney Utelah diterapkan untuk nolai post test kelompok jika ada perbedaan signifikan diantara mereka. Tes Mann Whitney U menunjukkan perbedaan signifikan antara kelompok percobaan dan kontrol untuk kelompok percobaan. Nilai rata-rata dari kelompok kontrol adalah 14,63 sementara itu 29,06 dalam kelompok percobaan (tabel 4). Ini membuktikan bahwa lembar kerja ternyata lebih efektif daripada metode tradisional dalam mengajar konsep yang berhubungan pada keseimbangan kimia. Didalam proses pembelajaran tradisional, guru biasanya berceramah dan siswa sebagai pendengar pasif. Disisi lain, dalam lingkungan belajar dengan lembar kerja, siswa dengan aktif berpartisipasi dalam proses pembelajaran. Dalam proses ini, siswa menggunakan peralatan-perlengkapan, membuat observasi, merekam data, menganalisa data dan menggambarkan kesimpulan. Demikian kegiatan-kegiatan yang dilakukan oleh siswa penting untuk membentuk pengetahuan abstrak menjadi pengetahuan konkret. Peserta kelompok percobaan juga menyatakan selama wawancara bahwa aplikasi ternyata efektif untuk belajar permanen. Pelajaran lain yang didapat, menyarankan bahwa beberapa kegiatan ini membantu siswa memahami konsep abstrak seperti keseimbangan kimia dan juga lembar kerja membantu mengajarkan topik yang sulit. (Ayas.......dst)

Selama diadakan wawancara dengan kelompok kontrol dan percobaan, para peserta pertama diminta untuk menjelaskan perubahan dalam keseimbangan dan keseimbangan konstan atas tambahan beberapa gas N2O4 pada HEAT+N2O4(g)         2NO2(g)reaksi pada temepratur dan volume konstan, dan kemudian menggambar sesuai dengan grafik waktu. Tabel 5 termasuk respon siswa pada pertanyaan ini. Itu menunjukkan bahwa siswa dalam kelompok percobaan bisa menjawab dengan akurat pertanyaan mengenai perubahan dalam keseimbangan dan keseimbangan konstan.  Siswa D dan E dikelompok kontrol tidak bisa menggambar grafik konsentrasi waktu dan tidak bisa membuat penjelasan detil. Ini mengungkapkan bahwa siswa D dan E tidak dapat memperhitungkan peningkatan konsentrasi zat yang ditambahkan dalam sebuah sistem yang seimbang. menurut Wheeler dan Kass(1978), grafik konsentrai waktu sangat efektif dalam pemahaman siswa tentang apa yang terjadi jika efek dibuat pada sebuah sistem yang seimbang. disamping itu, siswa menyatakan bahwa keseimbangan konstan meningkat jika zat ditambahkan pada sistem yang seimbang. salah satu kesalahan gambaran yang ditulis oleh Bergquest dan Heikkinen(1990) dalam pelajaran mereka bahwa siswa berpikir bahwa keseimbangan konstan berubah atas perubahan input dan jumlah produk. Selama wawancara, peserta kelompok kontrol dan percobaan kebanyakan bisa menggambardengan akurat grafik konsentrasi waktu dengan temperatur yang meningkat dalam reaksi (tabel 6). Siswa F dalam kelompok kontrol menyatakan bahwa keseimbangan kimia pindah pada produk tapi tidak bisa menggambar grafik. Disamping itu, semua siswa bisa menjawab dengan akurat pertanyaan mengenai perubahan nilai Kd dalam hubungannya dengan temperatur. Tabel 7 menunjukkan bahwa peserta terutama bisa menjawab dengan akurat pertanyaan mengenai keseimbangan dan keseimbangan konstan dengan perubahan volume dalam reaksi yang diberikan sedangkan siswa F memberikan jawaban salah mengenai keseimbangan konstan dan tidak bisa menggambar seperti dibawah tiga pertanyaan yang lain. Selain itu, siswa F menyatakan bahwa nilai dari keseimbangan konstan berubah dalam kasus perubahan volume. Seperti kesalahan konsep yang juga ditemukan dalam pelajaran lain yang dibawa oleh Yildirim(2000)da Yildirim  et al (2007).

Siswa dalam kelompok percobaan mencampur semua bahan yang diberikan sebelum membaca perintah dalam lembar kerja dan mengambil bermacam-macam bahan dari lemari di pelajaran sebelumnya. Itu mungkin dijelaskan dengan kurangnya partisipasi siswa dalam kegiatan laboratorium sebelumnya. Ozmen dan Yildirim(2005)meraih penemuan yang sama dengan baik. Dalam pelajaran berikutnya, siswa diawasi untuk bisa melakukan kegiatan sendiri dan menjadi lebih mudah dilaksanakan. Selama wawancara, siswa B mengatakan , dalam hubungan dengan kegiatan yang dikerjakan, ‘ saya bingung, kemudian datang ke laboratorium. Sebelumnya, kami biasanya mengatakan bahwa keseimbangan pindah kekiri atau kanan tapi saya tidak bisa mengerti. Sekarang saya bisa melihat apa yang terjadi saat keseimbangan sistem tidak seimbang.’ (tabel 8). Kutipan ini menyarankan bahwa percobaan dibawah kegiatan percobaan pada lembar kerja menarik perhatian siswa dan keseluruhan aplikasi membantu untuk memahami konsep. Mengenai kelas kimia, peneliti dalam literatur menyatakan bahwa siswa tidak bisa mendapatkan pengetahuan permanen, kecuali informasi dipindahkan berdasarkan  percobaan (Ayas, Cepni.......dst).  siswa  membuat observasi, merekam data, menggambarkan kesimpulan dari data dan dan jadi berperan aktif dalam proses sementara merekamelakukan percobaan di laboratorium (tamel, oral .........dst). Demircioglu.........dst(2004) menyarankan bahwa kelakuan diperoleh ketika siswa berperan aktif lebih permanen dan signifikan daripada jika hanya diperoleh dengan alat audio visual.

Siswa B dalam kelompok percobaan menyatakan selama wawancara bahwa melakukan percobaan atas dasar individu akan lebih baik. Selama observasi, kebanyakan siswa sama melakukan transaksi di aplikasi kelas pertama. Sejak siswa bekerja sendiri dalam lingkungan kelas tradisional, mereka menghadapi kesulitan  dalan kerja kelompok. Disisi lain, siswa membuat kerja kelompok dan bertindak sebagai sebuah kelompok dalam pelajaran berikutnya. Itu terlihat bahwa saat ini interaksi siswa-siswa dan guru-siswa menjadi lebih umum  dan baik. Siswa mulai menanyakan pertanyaan dalam kelompok. Selanjutnya; guru memandu siswa untuk berpikir dengan cara menanyakan pertanyaan. Pelajaran dilaksanakan membuktikan bahwa lingkungan laboratorium ditingkatkan tidak hanya aktifitas, bantuan, bertanggung jawab, observasi dan percobaan dan kesalahan dalam kelompok tapi juga minat belajar hingga pencapaian dalam kimia ( Ayas.........dst)

Kesimpulan dan rekomendasi

Penelitian ini dilksanakan untuk menentukan pengaruh lembar kerja pada pencapaian siswa atas fakto-faktor yang mempengaruhi keseimbangan kimia. Sebagai konsekuensinya, ditemukan bahwa lembar kerja meningkatkan pencapaian siswa mengenai faktor-faktor yang mempengaruhi keseimbangan kimia. Dalam hal ini, lembar kerja bisa dikembangkan pada dasar konseptual untuk topik kimia lain yang sulit  dipahami. Disamping itu, peserta menyatakan bahwa mereka menikmati kegiatan dan aplikasinya lucu. Penelitian yang lama pada dasar lembar kerja dalam berbagai macam mata pelajaran bisa digunakan untuk menemukan keefektifan mereka dalam tingkah laku yang mempengaruhi siswa.