Investigating Senior High School Students

International Journal of Educational Administration ISSN 0976-5883 Volume 3, Number 1, (2011), pp. 41-57 © Research India Publications http://www.ripublication.com/ijea.htm

Investigating Senior High School Students’ Conceptions of Introductory Chemistry Concepts Ruby Hanson*, Kodjo Donkor Taale and Victor Antwi Department of Science Education, University of Education, Winneba, Ghana, West Africa *Correspondent author Email: [email protected]

Abstract This research was to be a baseline study to unearth Ghanaian elective science students’ alternative conceptions at the start of their chemistry course at the SHS so that they could be corrected early enough. The study aimed at investigating students’ conceptions on properties of matterelements, compounds, mixtures, physical change, chemical change and the acid – base concept. It covered three representative schools with a population of four hundred and fifty students. These students completed a concept diagnostic test on basic introductory chemistry concepts necessary for the start of an elective chemistry course at Senior High School. Results indicated that beginning High school students have significantly gross misconcepts of greater than 42 % about basic chemistry concepts. This is statistically significant and will not auger well for effective teaching and understanding of further concepts. A lot of preparatory studies will be required before the commencement of a secondary school chemistry course for better grounding and understanding of chemistry concepts.

Introduction Schooling in Ghana consists of three main components: basic, secondary and higher education. The basic education comprises Primary and Junior High Secondary Schools. This is compulsory for all children between the ages of 6 – 15 years of age. It spans over a nine year period after which academically successful candidates in a national examination proceed to the Senior High School. Senior high education lasts for three years. From here, students pursue higher education in colleges, polytechnics and the universities. Basic education looks first at the Nature of Science which later progresses to assume the name Integrated Science at the Junior High schools (JHS). Introductory

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Ruby Hanson, Kojo Taale and Victor Antwi

chemistry concepts such as the structure of atoms, chemical reactions, chemical equations, types of chemical changes, solutions, the nature of chemicals, acids and bases are taught within a three year period. Biology and Physics are also introduced. It is important to know that all these different science fields are introduced not under their distinctive names but as Integrated Science. Students are introduced to these distinctive disciplines later on in the Senior High Schools (SHS). Chemistry has been regarded as a difficult subject for students by researchers, educators and teachers who teach them (Ben-Zvi, Eylon & Silberstein, 1982). Most chemistry concepts have been found by researchers to be abstract in nature though it acts as a link among the other science disciplines. Besides, the language of chemistry is difficult. Such abstraction and difficulties lead to the development of alternative concepts among students. These alternative conceptions become prior knowledge which hinders subsequent learning among students (Driver & Easley, 1978; Gilbert & Watts, 1983). It is therefore important to detect students’ prior conceptions or what is popularly known as previous knowledge in order to plan future lessons which will help to do away with these prior conceptions and help to replace them with accepted scientific views. This study aimed at investigating students’ conceptions on properties of matterelements, compounds, mixtures, physical change, chemical change and the acid – base concept

Literature Review The importance of students’ initial conceptions of science has become very important in the past few years. In the physical sciences, chemistry is the one for which the least research concerning students’ conceptions of underlying concepts has been undertaken (Ayas & Demirbas, 1997). Research has been done in Chemical Equilibrium by El-Gendy, (1984) and Hackling and Garnett, (1985) as researched by Ayas, (1993). Taber (2000, 2001) has also done appreciable studies of students’ preconceptions in the United Kingdom. According to Brigg and Holding (1986) and Laverty & McGarvey (1991) not much work has been undertaken in how students conceptualize underlying concepts in elements, compounds, mixtures as well as chemical change. Studies by Ben-Zvi, Eylon and Silbrstein, (1982) on students’ understanding of chemical reactions showed that students still had difficulties with basic aspects in understanding chemical reactions even at the end of their chemistry course. Abraham, Grzybowski, Renner & Marek (1992) showed that the chemical change concept was not understood by about 86 % of students in a study. In another study by Hesse and Anderson (1992), students had to explain three oxidation- reduction reactions. Analysis showed that students had difficulties in 1. chemical knowledge 2. conversation reasoning and 3. explanatory ideas. They thus concluded that the topic was more complex than teachers and text book

Investigating Senior High School Students’ Conceptions

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writers acknowledged and portrayed it. Griffiths and Preston (1992) noted that students when studying the Particulate Nature of Matter (PNM) had tendencies to transfer changes in macroscopic properties to the microscopic level. They also indicated that grade 12 students that they studied had 52 misconceptions on the fundamental characteristics of atoms and molecules. They concluded that some of the misconceptions were in parallel to the historical developments of scientific concepts. An overview of the arguments and findings above shows that students have conceptions that are different from scientific ones. These conceptions influence their understanding of scientific views that their teachers and textbooks present. Besides, traditional instruction methods have little or no effect on changing misconceptions or helping to develop authentic scientific concepts (Gilbert & Watts, 1978; Osborne & Witt rock, 1983). As indicated earlier, little research has been undertaken about students’ conceptions of introductory chemistry in the SHS. There is however no empirical data or research about students’ conception of introductory chemistry concepts in the Ghanaian SHS. This study will help to unearth students’ concepts of elements, compounds, mixtures, physical and chemical change as well as their concepts on acids and bases. These concepts are basic to any chemistry curriculum. Briggs and Holding (1986) have found out that teachers find it difficult to introduce these topics; thus students develop alternative conceptions through these teacher deficiencies besides their own difficulties in chemical knowledge, conversation reasoning and explanatory ideas. Purpose of the study This research was to be a baseline study to unearth students’ alternative conceptions at the start of their chemistry course at the SHS so that they could be corrected early enough. In this way solid chemical concepts would be built by students early enough to aid them in their pursuits of higher academic chemistry courses at the tertiary levels of their education. This purpose elicited the main research question for the study: What are the conceptions of senior high school introductory elective chemistry students’ conceptions at the beginning of their chemistry course?

Experimental Design A test on conceptual understanding of the said concepts was developed by selecting and validating questions from National and International question banks. As the questions were selected from question banks they were accepted as valid and reliable for the study. The test consisted of two sections. The first part consisted of paired questions. The first question asks about a chemical or physical effect whiles the follow up or second question asks for the reason for the observed effect. These paired questions were selected from conceptual questions from the chemical concepts inventory of the American Chemical Society - Journal of Chemical Education, Division of Chemical Education of the American Chemical Society, 2010, (http://www.cde.ca.gov/ta/tg/sr/resources.asp). Simple probes on elements, compounds, mixtures mass and dissolution, chemical equations types of reactions and precipitation were assessed as students had studied all of these in the JHS. These basic

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questions assessed their prior conceptions, and their readiness to study elective chemistry. In all, there were 12 multiple choice questions and 15 constructed response or probing test items. An example of a paired question used in the first section is indicated below. 1. Iron combines with oxygen and water from the air to form rust. If an iron nail were allowed to rust completely, one would find that the rust weighs 1. less than the nail it came from 2. the same as the nail it came from 3. more than the nail it came from 4. it is impossible to predict 1. 2. 3. 4. 5.

Rusting makes the nail lighter. Rust contains iron and oxygen The nail flakes. The iron from the nail is destroyed. The flaky rust weighs less than the iron

The type of constructed response questions are as indicated below. Complete the word equation below by adding the name of the missing substance. Explain your answer. 3. Nitric acid + potassium hydroxide I chose this answer because

→

……………… + water.

………………………………………………………………………………………… 4. Identify the type of reaction observed in the equation below and explain your answer. Sodium chloride → Sodium + Chlorine 2NaCl (l) → 2Na (l) + Cl2 (g) It is a …………………………reaction, because ………………………………………………………………………………………… The test was administered to a stratified random sample of 450 students across the Central Region of Ghana. It was administered under normal class conditions. Students were assured that the results were not going to count as part of their term assessment. Senior High Schools in Ghana are not basically community schools as implied in Western countries. Therefore candidates from all regions over the country and from different ability schools meet to start a common pre-tertiary programme in the SHS. There was therefore no need to carry out this base line analysis in different regions of the country. In analyzing the results, percentages of wrong choices for multiple choice questions were calculated. Answers for constructed responses were analyzed to assess


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students’ alternative conceptions. The ‘No response’ answers were also worked out but not used in discussion. An overall achievement score for each school was calculated for statistical comparisons between the different schools.

Results The results from the multiple choice tests are shown in Table 1 while the explanatory section is in Table 2. Students’ written explanations were examined in detail for the concepts investigated. Table 1: Percentages of misconcepts from multiple choice test. W= Wrong option X= No response Item No School A W X 1 40 2 52 3 35 4 20 5 52 6 6 45 7 52 6 8 28 9 46 4 10 36 11 50 2 12 28 -

School B W X 48 48 36 23 68 6 49 54 4 26 40 44 62 6 60 -

School C W X 42 56 38 28 70 4 42 58 8 32 40 10 38 66 6 52 -

Table 2: Percentages of misconcepts from constructed response test. W= Wrong option X= Wrong explanation Item 13a 13b 13c 14a 14b 14c 14d 15a 15b 15c 16

School A 18 8 18 6 18 8 38 4 20 34 6 30 8 48 2 48 6 20 12 24 2

School B 28 6 32 8 20 10 40 34 12 36 4 32 6 50 4 50 8 26 10 42 2

School C 36 4 36 10 30 36 2 36 10 48 6 44 4 32 14 48 8 30 4 40 4

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Ruby Hanson, Kojo Taale and Victor Antwi 16b 17a 17b 18a 18b 19a 19b 20a 20b 21a 21b 22a 22b 23a 23b 24a 24b 25a 25b 25c 25d 25e 25f

36 44 32 52 34 48 38 42 36 40 56 28 40 48 50 22 30 26 34 24 32 36 34

10 4 16 20 12 10 24 16 34 26 34 16 22 18 8 6 16 6 4 4 2

34 53 46 60 48 52 50 52 40 52 58 66 50 54 62 64 64 44 42 40 46 50 32

6 6 12 7 14 8 22 18 34 32 40 22 22 16 16 6 20 6 2 4 4

38 50 40 60 48 46 50 58 44 50 62 48 42 50 66 46 54 40 40 26 45 48 48

6 4 6 12 16 6 24 18 34 30 44 24 24 14 10 8 18 6 4 2 6 -

Table 3: Anova Analysis. Descriptive Statistics Constructed type School A

Number of errors

N 34

Mean 34.6471

School B

Number of errors

34

45.5588

School C

Number of errors

34

44.5588

These mean values may not be significantly different. In order to check for significance, an ANOVA test was performed and the result presented in the table 4.


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Table 5: ANOVA Test. ANOVA Sum of Squares df Mean Square F Sig. Between Groups 2474.176 2 1237.088 11.095 .000 Within Groups 11038.529 99 111.500 Total 13512.706 101

The p-value (P =.000) of the ANOVA table is less than .001 therefore there is a significant difference among the three groups. Responses mistakes were frequent than response misconception and non response. In algebraic terms, the Response mistakes > Response misconception > Non response. The result of the Least Significance Difference (LSD) test is presented in Table 6. Table 6 Multiple Comparisons (I) Constructed (J) Constructed Mean Std. type type Difference (I-J) Error

School B -10.91176* 2.56102 * School C -9.91176 2.56102 * School B School A 10.91176 2.56102 School C 1.00000 2.56102 * School C School A 9.91176 2.56102 School C -1.00000 2.56102 *The mean difference is significant at the 0.05 level. School A

Sig. 95% Confidence Interval Lower Upper Bound Bound .000 -15.9934 -5.8301 .000 -14.9934 -4.8301 .000 5.8301 15.9934 .697 -4.0816 6.0816 .000 4.8301 14.9934 .697 -6.0816 4.0816

At 95 % confidence level, it was noted that there was a significance difference between the following pairs • School A and School B • School A and School C • There was no significance difference between Schools B and C.

Discussion The written responses indicated that many students ready to read elective chemistry were unable to make meaning of certain ideas. A greater percentage of students were unable to apply their chemical knowledge in new situations as observed from their

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responses. They could also not classify substances which were used in everyday life such as salt, water and aluminum as elements, compounds or mixtures. For example, they could not classify water as a compound and air as a mixture when asked about these. The gross mean misconcepts score was 41.59 %. Percentage misconcepts for schools A, B and C were 34.6, 45.6 and 44.6 % respectively ANOVA with Friedman’s test and Turkey test between and within participants and schools showed a statistical significant difference of 0.000 and 0.847 respectively. School A showed a slightly less percentage of wrong responses (34.6 %) as compared to schools B and C (45.6 and 44.6 % respectively). School B registered the most misconceptions. For high percentages of such misconceptions in very basic concepts at the start of a course implies that teachers will need to carefully teach these concepts all over before the actual start of the new programme. Misconcepts for elements, compounds and mixtures concepts, equations and types of reactions concepts as well as the bonding and precipitation concepts were quite high. Misconceptions in these areas were high and ranged between 50-66 %. It was especially difficult for students to assign scientifically correct reasons for choices made. In most cases, no reasons were even assigned. It indicated that introductory concepts are not mastered effectively by JHS students before entry into the SHS. In a developing country like Ghana, this could be attributed to the non-availability and non-use of laboratories for practical activities as well as instructional approaches. Text books could also be a contributory factor but this was not assessed in this research.

Conclusion Since students’ early concepts have great effect on their later learning, it is imperative that such alternative conceptions are identified and corrected in a positive direction so that students develop these concepts scientifically. Obtained results confirmed High School students’ difficulties with introducing basic concepts. Studies done in British and American schools also showed that 25 % of 15 –year olds had acceptable conceptions while 86 % of secondary students had misconceptions about chemical change (Abraham et al., 1992; Freyberg & Osborne, 1985). There is no difference between a wrong concept chosen and the follow up explanation. This was observed mostly in schools B and C as already indicated. These two types of responses (mistakes and misconcepts) often occur than “response error” only. Once a response error occurs, most likely its follow up explanatory concept will also be wrong as observed from students’ outcomes. This observation is a clear indication of an earlier non conceptual understanding of previously learned facts. As much as possible such lapses must not be allowed to occur as they hinder further understanding of chemical concepts.

Implications for Chemistry Education and the Teaching of Chemistry Students’ preconceptions affect the interpretation of new knowledge and also make its


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comprehension impossible (Mas, Perez & Harris, 1987). Such conceptions as studied in the research are the building blocks of chemistry. It generates links between further topics and concepts that must be mastered for better conceptual understanding. As Freyberg and Osborne put it, “… the active construction, testing and acceptance of new ideas can only be accomplished by the learner, p. 83”. Chemistry must be taught in other more interactive ways such as engaging in more practical activities, use of concept maps and other hands-on activities so that students overcome their misconceptions. It will be important for science teachers, researchers, and curriculum developers to collaborate to design appropriate teaching materials and strategies to develop such introductory concepts effectively. Using everyday experiences in their text and teaching situations will help students to apply their chemical knowledge to new situations in their environments. A course related to students’ alternative conceptions and methods to eliminate them could be provided in teacher education programmes in order to equip teacher trainees with adequate scientific knowledge so as to be able to apply conceptual change strategies when they teach in the JHS and SHS (Sevgi, Nurdane, Yezdan, Ayla & Oktay, 2009). Above all, if teachers have prior knowledge or the possibilities of alternative conceptions of students, then various instructional methods could be developed based on the identified misconceptions.

References [1]

[2]

[3]

[4] [5] [6]

[7]

Abraham, M. R., Grzybowski, E. B., Renner, J. W., & Marek, E. A. (1992). Understandings and misunderstandings of eight graders of five chemistry concepts found in textbooks. Journal of Research in Science Teaching , 29, (2), 105–120. Ayas A., & Demirbas, A. (1997). Turkish Secondary students’ conceptions of introductory chemistry concepts. Journal of Chemical Education , 74 (5), 51852. Ayas, A. (1993). A study of teachers’ and students ‘views of the Upper Secondary chemistry curriculum and students’ understanding of introductory chemistry concepts in the Black Sea Region of Turkey, PhD. Thesis;England, University of Southampton. B., Laverty D. T., & McGarvey J. E. (1991). A constructivist’ approach to learning. Educ Chem , 28, 99-102. Ben-Zvi, R., Eylon B., & Silberstein, J. (1982). Students’ visualization of a Chemical Reaction. J Chem Educ , 24 (4), 117-120. Briggs, H., & Holding, B. (1986). Aspects of secondary students’ understanding of elementary ideas in chemistry. Full Report; Leeds, CLISP University of Leeds. Driver, R., & Easley, J. (1978). Pupils and Paradigms: A review of literature related to concept development in adolescent science students. Stud Sci Educ , 5, 61-84.

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[9]

[10]

[11] [12] [13]

[14] [15]

[16] [17]

Ruby Hanson, Kojo Taale and Victor Antwi El-Gendy, O. E. (1984). A study of the student understanding of the Basic Chemistry concepts in Egyptian secondary schools. PhD. UK, University of Cardiff. Gilbert, J. K., & Watts, D. M. (1983). Concepts, misconceptions and alternative conceptions: Changing perspectives in science education. Studies in Science Education , 10, 61-98. Griffiths A. K., & Preston, K. R. (1992). Grade 12 students’ misconceptions relating to fundamental characteristics of atoms and molecules. Journal of Research in Science Teaching , 29, 29: 611-628. Hackling M. W., & Garnett, P. J. (1985). Misconceptions of chemical equilibrium. Eur. J. Sci Educ , 7, 205-214. Hesse, J. J., & Anderson, C. W. (1992). Students’ conceptions of chemical change . Journal of Research in science teaching , 29 (3), 277-299. Mas, C. J. F., Perez, J. H., & Hariris, H. H. (1987). Parallels between adolescents, conception of gases and the history of chemistry. J Chem Educ, 64(7), 616-618. Osborne, R., & Freyberg, P. (1985). Learning in science: the implications of children’s science,Portsmouth NH pp 82-89.Heinemann. Sevgi A., Nurdane, A., Yezdan B., Ayla, C. D., & Oktay, B. (2009). The contribution of Constructivist Instruction Accompanied by Concept Mapping in Enhancing Pre-service Chemistry Teachers’ Conceptual Understanding of Chemistry in the Laboratory Course. J Sci Educ Technol , 18, 518-534. Taber, K. S. (2000). Chemistry lessons for universities? A review of constructivists’ ideas, U. Chem.Educ., 4, 63-72. Taber, K. S. (2001). Constructing chemical conceptions in the classroom using research to inform the practice. Chem Educ. Res. Pract. , 2, 43-51.

Appendix 1 Chemistry Concept Test Carefully consider each question and indicate the best answer for each. Some of the questions are paired. The first question asks about a chemical or physical effect and its follow up question asks for the reason for the observed effect. 1. Which of the following must be the same before and after a chemical reaction? a. The sum of the masses of all substances involved. b. The number of molecules of all substances involved. c. The number of atoms of each type involved. d. Both (a) and (c) must be the same. e. (e) Each of the answers (a), (b) and (c) must be the same. 2. What is the mass of a solution when 1kilogram of salt is dissolved in 20kilograms of water?


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a. 19Kg b. 20Kg c. Between 20 and 21Kg d. 21Kg e. More than 21Kg. 3. An …………… is a base which dissolves in water a. acid b. oxide c. alkali d. element 4. Two ice cubes are floating in water.

After the ice melts, the water level will be a. Higher b. Lower c. the same 5. What is the reason for your answer in question 4? 6. A 1.0 gram sample of solid iodine is placed in a tube and the tube is sealed after all of the air is removed. The tube and the solid iodine together weigh 27.00 grams.

The tube is then filled and heated until all of the iodine evaporates and the tube is filled with iodine gas. What will be the weight after heating it? a. less than 26.0 grams

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Ruby Hanson, Kojo Taale and Victor Antwi b. 26.0 grams c. 27.0 grams d. 28.0 grams e. More than 28.0 grams.

7. What is the reason for your answer to question 6? a. A gas weighs less than a solid b. Mass is conserved c. Iodine gas is less dense than solid iodine d. Gases rise e. Iodine gas is lighter than air. 8. Iron combines with oxygen and water from the air to form rust. If an iron nail were allowed to rust completely, one would find that the rust weighs a. less than the nail it came from. b. the same as the nail it came from. c. more than the nail it came from. d. it is impossible to predict. 9. What is the reason for your answer to question 8? a. Rusting makes the nail higher. b. Rusting contains iron and oxygen. c. The nail flakes away. d. The iron from the nail is destroyed. e. The flaky rust weighs less than iron. 10. Salt is added to water and the mixture is stirred until no more salt dissolves. The salt that does not dissolve is allowed to settle out. What happens to the concentration of the salt in solution if water evaporates until the volume of the solution is half the original volume? (Temperature remains the same).

The concentration a. increases b. decreases c. stays the same


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11. What is the reason for your answer to question 10? a. There is the same amount of salt in less water. b. More solid salt forms. c. Salt does not evaporates and is felt in solution d. There is less water. 12. Which of these is not evidence of a chemical change? a. temperature b. melting c. colour change d. appearance of a solid

Elements, Compounds and Mixture Concept 13. Try to explain what you think each of these chemical terms mean. a. Elements b. Compound c. Mixture 14. Each diagram shows an element, compound or mixture. Decide which each diagram is and explain your answer.

This diagram shows particles in ……………………………….. ……………………………………………………….

because

This

because

diagram

shows

particles

in

………………………

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…………………………………………….

This diagram shows particles ………………………......

This diagram shows …………................................

in

particles

………………………

in

……………………

because

because

15. When substances are mixed their molecules become mixed as it contains more than one type of atom or molecule. Label each of the diagrams below as a single substance or a mixture.

……………………

…………………..

…………………..


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Mass and Dissolution Concept 16. Some water was fetched into a beaker and the mass measured using a balance. The total mass was 100g. Then 20g of salt was weighed and added to the water. The salt sank to the bottom of the beaker. After 10 minutes the salt could not be seen. a. Fill in the boxes to show what you think the mass of the beaker and its contents would be when the salt was first added and then after the salt could not be seen.

b. Where did the salt go? ………….…………………………………………………………………………

Physical –Chemical Change//Changes in Chemistry 17. The diagram below shows some substances undergoing change-before and after sometime. Decide whether the change is physical or chemical and try to explain your reason. Some Magnesium is heated in oxygen until it burns.

Before

After

This is a …………………………………… change because ………………..

Equations and Types of Chemical Reaction Complete the word equation by adding the name of the missing substance. Explain your answer.

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18. Nitric acid + Potassium hydroxide

……………………… + water

1 chose the answer because ……………………………………………………… 19. Zinc + Oxygen

………………………………………………

1 chose the answer because ………………………………………………………... Identify the types of reaction observed in the equation below and explain your answer. 20. Sodium Chloride 2 NaCl (l)

Sodium + Chlorine 2 Na (l) + Cl2 (g)

It is a ……………………………………reaction because........................

Bonding and Precipitation Choose True and False as a response to the statement made about ionic bonding and assign a reason to your choice. 21. A sodium atom can only form one ionic bond because it only has one electron in its outer shell to donate………………………………………………………… 22. The reason why a bond is formed between chloride ions and sodium ions is because an electron has been transferred between them. ……………………………………………………………………………………… 23. An ionic bond is the attraction between a positive ion and a negative ion. ……………………………………………………………………………………… 24. Aluminum has a type of bonding called metallic bonding ………………………… 25. Spot the bonding in


Sodium atom ………………….

Sodium chloride

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Mg metal Lattice

Liquid water

………….............

………………

Oxygen gas

Ammonia molecule

Information on Authors Mrs. Ruby Hanson is a Science educator at the Chemistry Education Department, University of Education, P.O.BOX 25, Ghana, West Africa. She is the main correspondent to whom information regarding this intended publication should be addressed. Telephone number is +233 20 812 6299; email address s: [email protected]. Dr. Kodjo Donkor Taale is a Science educator at the Science Education Department, University of Education, Winneba. Email address is [email protected]. Victor Antwi is also a Science educator at the Science Education Department, University of Education, Winneba. Email address is [email protected]. Full Address of Correspondent author Email : [email protected]. Chemistry Education Department, University of Education, P.O.BOX 25, Ghana, West Africa

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