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Citation: Jakubˇcinová, J.; Feszterová,
M.; Silliková, V. Active Learning in
the Extraction of Organic Compounds:
A Study of Undergraduate Chemistry
Students. Educ. Sci. 2024,14, 1051.
https://doi.org/10.3390/
educsci14101051
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Revised: 21 September 2024
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education
sciences
Article
Active Learning in the Extraction of Organic Compounds:
A Study of Undergraduate Chemistry Students
Jana Jakubˇcinová1, Melánia Feszterová1, * and Veronika Silliková2
1Department of Chemistry, Faculty of Natural Sciences and Informatics, Constantine the Philosopher
University in Nitra, Tr. A. Hlinku 1, 949 01 Nitra, Slovakia; jjakubcinova@ukf.sk
2
Institute of Inorganic Chemistry, Slovak Academy of Sciences, DúbravskáCesta 9, 845 38 Bratislava, Slovakia;
veronikasillik963@gmail.com
*Correspondence: mfeszterova@ukf.sk
Abstract: This study investigates the impact of active learning on the acquisition of competencies and
learning outcomes in the context of organic chemistry education. Specifically, this study focuses on
the implementation of active learning in the extraction of an unknown mixture of organic compounds
using acidic and basic solutions. This research is based on an “ex post facto” study involving
40 first-year
undergraduate students who are pre-service chemistry teachers at a Slovak public
university. This study aims to analyse students’ performance, identify common problems encountered,
and assess the advantages and disadvantages of the active learning approach. The data collection
instruments included a structured report on best practices in university education and a questionnaire
to evaluate the experiences and assessment systems used. This study compares the effectiveness of
online and face-to-face teaching methods for practical chemistry coursework. The key findings from
the comparison of these methods are the differences in learning outcomes achieved, e.g., answers to
tasks 2–6 from the questionnaire. Group B respondents had a higher number of correct responses and
lower variability compared to Group A respondents. This difference may indicate an improvement
in comprehension and effectiveness of instruction over the period. Differences in scores between
the groups may be due to random variability in the composition of the groups, which we found
through statistical analysis. Full-time students felt more engaged and more satisfied. More than half
of the students said that they preferred face-to-face interactions to help them better understand the
material. While online instruction provided greater flexibility and accessibility, students felt that
they lacked hands-on interaction, which negatively impacted their acquisition of practical skills. The
results indicate that active learning, particularly hands-on laboratory exercises, had a positive impact
on the acquisition of professional competencies and students’ learning outcomes. This study also
highlights the advantages of active learning in practical chemistry education.
Keywords: development learning; laboratory exercise from organic chemistry; acid-base extraction;
separation techniques; active learning (learning by doing); distance learning/self instruction
1. Introduction
The success of education is influenced by a number of factors, such as the characteris-
tics of educational institutions, the specifics of the curriculum, the structure and content of
existing databases, the volume of information stored in them, and others [
1
]. Active learn-
ing is a pedagogical method used by teachers to engage students in the classroom, i.e., the
emphasis is on student interaction with the learning content and their active participation
in the learning process. It is associated with the concept of “learning by doing”, in our case,
laboratory exercise. The main goal of active learning in chemistry is to encourage students
to develop a deeper understanding of topics and their applications in the real world rather
than simply memorising facts. This method seeks to create an environment where students
not only understand what they are learning but also why it is important and how it can
be applied.
Educ. Sci. 2024,14, 1051. https://doi.org/10.3390/educsci14101051 https://www.mdpi.com/journal/education
Educ. Sci. 2024,14, 1051 2 of 19
Active learning methods can significantly improve students’ acquisition of practical
skills; however, the question of whether these methods are equally effective in an online
environment remains open. Given the growing importance of online learning in recent
years, it is imperative to investigate how this form of instruction affects student outcomes
when compared to traditional face-to-face tutorials. Teaching organic chemistry at uni-
versity is known to be challenging, and effective methods are needed to support students
in acquiring both theoretical knowledge and practical skills. This study aims to compare
the effectiveness of online and face-to-face teaching methods in the context of teaching
Laboratory Exercises in Organic Chemistry at a university. The main unit of analysis is
the impact of these methods (online vs. face-to-face teaching) on students’ acquisition of
professional competencies and learning outcomes. In this study, we focused specifically on
extraction with acidic and basic solutions. The focus was on extraction and its importance
in education as a tool for developing practical skills, scientific thinking, and real-world
understanding of chemical concepts.
Extraction on Specific Example
According to Kustitskeja et al. [
1
], student retention is a significant challenge for uni-
versity education institutions and should lead to the acquisition of professional knowledge.
The knowledge that student teachers acquire while preparing for their profession also
relates to laboratory techniques, such as extraction.
Extraction is a key tool for separating and isolating the components of mixtures, and it
has many applications. Extraction is an important process in chemistry, pharmaceuticals,
food and other industries that allows one substance to be separated or isolated from another
by selective dissolution in different solvents. This process is of wide practical importance
and can be used for a variety of purposes. The practical importance of extraction is in the
following fields: pharmaceuticals (isolation of medicinal substances, vitamins, or antioxi-
dants from natural sources), food processing (production of essential oils, flavourings, and
colourings from natural raw materials—fruits, spices, or herbs), petrochemistry and refin-
ing (separation of different components of mixtures—oils, gaseous substances, or various
hydrocarbons, in petroleum refining or petrochemical processes), environmental protection
(removal of contaminants from water or soil, which is important for wastewater treatment
or rehabilitation of contaminated areas), research and analysis (isolation and purification
of substances for further analysis), metal mining (separation of precious metals from ores
and minerals), industrial chemistry (extractors as part of industrial processes—production
of plastics, textiles, paper, and other products where there is a need to separate, purify, or
concentrate certain ingredients), cosmetics industry (isolation of plant extracts, oils, and
other natural ingredients used in cosmetic products).
Solvent extraction (SE) belongs to the group of classical analytical techniques. This
analytical technique is used for the extraction of inorganic compounds after complexation
with organic ligands as well as for the preconcentration and separation of solutes. It can
also be applied in various industries [2].
In this paper, we have focused on the analysis of a specific application of the extraction
method, followed by a discussion of its advantages and limitations. Incorporating extrac-
tion into teaching enhances the learning process and is beneficial (the acquisition of skills
and new knowledge) for students. The method of extraction can help pre-service teachers
better understand and subsequently teach basic chemistry concepts (conservation of mass
and separation methods) and the practical application of scientific procedures. Laboratory
skills acquired during extraction are important not only for professional mastery of the
content but also for the subsequent effective transfer of new knowledge to students. The
applied method of extraction builds on the science education standards in the Innovated
State educational programme [
3
] which emphasises teachers’ hands-on involvement in
laboratory activities as a key component in building their pedagogical content knowledge.
For example, the educational standard for the subject of chemistry is oriented to the
objectives and principles of science education for grade 2 (lower secondary education)
Educ. Sci. 2024,14, 1051 3 of 19
primary schools [
4
] and secondary schools [
5
]. in the thematic units covering the basic
concepts of chemistry (substances and their properties, chemical reactions) emphasises the
need for practical experience in the laboratory for successful teaching of scientific processes
and concepts, such as separation methods (extraction, filtration, distillation, crystallisation,
chromatography), and investigation of solutions and chemical compounds.
Many experiments have used the separation extraction technique. Examples include
extraction of plant pigments, foods, and natural products [
6
]. These are experiments in
which the extraction method can be combined with other laboratory separation techniques
such as paper chromatography. Based on this, the teacher can explain the material and
extend the chemical knowledge already acquired at the lowest levels of study using or-
ganic chemistry lab experiments, deepening the understanding of acid-base reactions and
topics such as chemical structure, density, and solubility [
7
]. The technique mastered in a
simple experiment provides opportunities for students, pre-service teachers, and pupils to
apply the acquired skills to other interdisciplinary fields (biology, environmental science,
physics, etc.).
Extraction is an important chemical separation technique that is essential in education,
especially in chemistry and laboratory research, and includes the following:
Theoretical knowledge and its application: Students learn to understand the prin-
ciples of solubility, acidity, basicity, and other chemical concepts in a realistic setting.
Extraction allows students to apply their theoretical knowledge of chemistry to specific
experimental situations.
Skills working in the laboratory: Students learn to work in a laboratory environment,
follow safe work practices, and avoid the hazards associated with handling chemicals [
8
].
As Yeerum et al. [
9
] state, part of the reason is that higher education faces additional
challenges due to the lack of hands-on experiments and the increasing number of students
in elementary school chemistry who are hindered in their practical skills [10].
Problem solving and logical thinking: Problem solving is part of daily activities [
11
].
Students have to decide what solutions to use, what concentration to use, and what
procedures to choose. In the final stage, they have to consider how they will interpret the
results. Extraction requires critical thinking and problem-solving skills related to working
in a laboratory. Problem solving with thinking is considered one of the most important
skills for successful learning in the 21st century [11].
Emphasis on experimental methods: Students learn laboratory skills, such as how
to prepare samples for analysis, perform reactions, and analyse results. Extraction al-
lows students to gain experience in experimental procedures that are key to research and
scientific advancement.
Systems thinking: As per Tümay [
12
], in chemistry education, it is necessary to
learn the subject matter in a meaningful way. Consequently, it is important to develop a
framework to implement systems thinking from a chemical perspective. Systems thinking
is an indispensable aspect of our discipline through a cycle of (1) modelling systems,
(2) prediction, and (3) retrospection.
Research potential: Students will become familiar with research topics and applications
that use extraction, which may increase their interest in further study. Extraction is used in
a variety of scientific disciplines, including chemistry, biochemistry, and pharmacology.
Improving critical thinking [
13
]: Students will learn to consider a variety of factors
(choice of solvent, reaction conditions, and separation methods) that develop their ability
to think critically and solve complex problems.
Data analysis: Data analysis is responsible for examining a set of data in order to draw
conclusions about the information in order to make decisions or to expand knowledge
on a specific topic [
14
]. Students will learn to examine and interpret the results, draw
conclusions, and discuss their meaning. Performing an extraction involves analysing and
interpreting the data obtained. According to the Villegas-Ch. et al. [
14
] data analysis
subjects the data to various operations in order to obtain precise conclusions that help
achieve the proposed objectives.
Educ. Sci. 2024,14, 1051 4 of 19
Observation skills and their development: Students learn to observe, analyse, and
interpret the results of experiments, which is a key skill in the field of scientific research.
Extraction also involves the visual observation of changes in colours, phases, and patterns.
Environmental and ethical aspects: Discussions on the ethical and environmental
aspects of extraction will help students understand the impact of chemical processes on the
environment and society. Increases in consumption, decreases in energy resources, lack of
or inability to use renewable energy resources, etc., are among the many factors that affect
air quality as well as the level of civilisation in societies [15].
The paper includes a description of the extraction procedures and a discussion of
the applications and advantages of this method using a specific example.. Sharing new
experimental results, analysing specific applications of the method, discussing the benefits
and limitations of extraction, etc. The results achieved in the educational process of pre-
service chemistry teachers are compared from the pandemic period, i.e., online education,
with the results achieved in face-to-face teaching for learning both chemical theory and
practical work. We agree with the authors Salta, Zois, and Tsiortos [
16
] that the COVID-19
pandemic forced educators to change methods of teaching and learning. According to
Li et al. [
17
], teaching driven by big data analysis and other informational technologies
has become a development trend and a hot research topic in the educational information
field. Familiarity with the extraction technique can provide students with practical skills
that are useful not only in a scientific career but also in a broader context, and help them
better understand the processes of scientific research. Descriptions of extraction procedures,
discussion of the applications and advantages of this method, and concrete examples and
experiments are a good basis for expanding knowledge in the field and acquiring new
knowledge essential from the point of view of the educational process.
2. Materials and Methods
The methodology involved the implementation of active learning in chemistry lab-
oratory exercises, focusing on an independent investigation, group activities, analysing
results, working through the problem, reflection and discussion, and sharing results. The
study also utilised a scoping review methodology, which involved a literature search and
the identification of eligible studies published between 2017 and 2023. The study sample
consisted of 40 students enrolled in the Department of Chemistry at a University in Slo-
vakia, divided into two groups: Group A (2019/2020, 2020/2021) and Group B (2021/2022,
2022/2023). The students were informed of a questionnaire that was prepared in order to
improve the quality of education and increase their knowledge. The data collection process
included the use of a structured report on best practices in university education, interviews,
and a questionnaire to assess the best practice experiences and the assessment system used.
Additionally, prior to the laboratory exercises, interviews were conducted with each respon-
dent to gather their insights and actively involve them in the exercise. We focused on the
results of the interviews, which were normalised and compared to show a true knowledge
acquisition comparison between the two groups and differences in the knowledge gained.
The results showed that the groups were equal when comparing knowledge.
The questionnaire consisted of 7 questions, including 1 open, 3 closed, and 3 semi-open
items. The closed-ended questions focused on the theoretical knowledge acquired by the
students and their applications, while the semi-open and open-ended questions provided
the respondents with the opportunity to express their opinions and further insights into
the issues under study. This study aimed to analyse the results of the implementation of
active learning in the 1st year of undergraduate students with respect to the acquisition of
students’ competencies, their learning outcomes, and the advantages and disadvantages of
the experiment. The data collected from the questionnaire and interviews provided valuable
insights into the students’ performance and the common problems encountered during
the exercise. This study also compared the evolution of online and face-to-face teaching
methods for practical chemistry coursework, shedding light on the impact of the COVID-19
pandemic on laboratory teaching and learning. Learning was combined, i.e., synchronous
Educ. Sci. 2024,14, 1051 5 of 19
(live exercises presented by the teacher) and asynchronous. The specific learning procedure
was a laboratory exercise as an active method. This was clearly defined and planned for
both the groups (A and B). Equivalent materials and activities were developed for both
the groups. Both groups A (online) and B (face-to-face), were exposed to the same types
of activities on the topic of extraction. Online tools were used to simulate the laboratory
exercise and discussion forums. For group B (face-to-face), analogous activities were
performed in the laboratory. The materials and procedures provided in face-to-face training
were identical to those used online. ICT (virtual lab, video discussion) was implemented on
the LMS Moodle platform for group A (online). The method of teaching in online mode was
with the help of LMS Moodle and students used technical devices like computers, tablets
and internet connection. For group B, similar tools were used, and students had the same
opportunities to engage. The same criteria and assessment methods were used for both
groups. As part of the assessment, we continuously monitored the work of the students
in both groups and evaluated the effectiveness of active learning in both environments.
We then collected feedback from students through a questionnaire on how the methods
were perceived and what problems were encountered. To ensure the same type of active
learning in both groups, the planning and implementation of activities, materials, and
assessments were ensured to be identical. A consistent approach to methodology and
assessment ensured that students in both settings received the same quality of education
and learning opportunities.
Research problem: How does the implementation of face-to-face active learning affect
the acquisition of professional competencies and learning outcomes of undergraduate
students compared with online teaching in a Laboratory Exercise in Organic Chemistry?
Hypothesis: Active learning, particularly hands-on laboratory exercises in the extrac-
tion of organic compounds, leads to significant improvements in students’ professional
competencies and learning outcomes compared with online learning methods.
The extraction method is widely used in scientific research, industry, and education,
allowing for the separation, identification, and isolation of substances, which significantly
impact various aspects of our daily lives. This study aimed to investigate the understanding
of extraction with acidic solutions by students in a combined Chemistry Teacher Education
programme. The study utilised a qualitative case study design, which is an empirical
method that examines real-world phenomena by considering contextual conditions related
to extraction. The case study design systematically explored the extraction method using
a specific example to understand its characteristics, dynamics, and contexts. Scheme 1
outlines the key elements of the case study design.
Educ. Sci. 2024, 14, x FOR PEER REVIEW 6 of 19
Scheme 1. Key elements of design study
According to Huesca et al. [18], using an experimental design for students in under-
graduate engineering programmes, a pre-test–post-test analysis revealed that the focus
groups showed significant improvement in normalised learning gain values compared to
the control groups.
2.1. Research Samples
This study employed a purposive method to extract organic maer from acidic and
basic solutions. Participants in the study were students enrolled in the Department of
Chemistry at a University in Slovakia. The respondents consisted of 40 students, divided
into two groups: Group A, comprising 20 1st-year students from the academic years
2019/2020 and 2020/2021 (A1 = A2: 20 respondents), and Group B, comprising 20 1st-year
students from the academic years 2021/2022 and 2022/2023 (B1 = B2: 20 respondents).
Group A students took the online course Organic Chemistry Laboratory Exercise, while
Group B students took the full-time course. The students who participated in the study
were prospective chemistry teachers and took the Organic Chemistry I and Organic
Chemistry Seminar concurrently with the Organic Chemistry Laboratory Exercise course.
2.2. Experimental Part
Extraction with Acid and Alkaline Solutions
In this study, we present an example of an integrated laboratory exercise focused on
the extraction of an unknown mixture of organic compounds (benzoic acid, β-naphthol,
and p-nitroaniline) using acidic and basic solutions. The exercise consisted of the follow-
ing components: Motivation—a brief introductory input, analogies, and interesting tasks
T1a–1c, which the students worked on after studying the topic from the literature, fol-
lowed by answering questions in the questionnaire. These sections contribute to the over-
all understanding of the laboratory exercise and its educational significance.
Education method: The education method aspect is based on students’ active learn-
ing in relation to a specific topic. The exercise aimed to engage students in understanding
the principles of extraction, preparation of solutions, and the factors influencing the
course of extraction. This method was designed to encourage students to apply theoretical
knowledge to practical scenarios.
Teacher competency represents the knowledge, understanding, skills, and intellec-
tual abilities of the teacher and students, which are essential for the successful implemen-
tation of the exercise. Therefore, teacher education plays an important role in developing
teachers’ knowledge and skills related to the use of technology in the classroom [19].
Scheme 1. Key elements of design study.
Educ. Sci. 2024,14, 1051 6 of 19
According to Huesca et al. [
18
], using an experimental design for students in under-
graduate engineering programmes, a pre-test–post-test analysis revealed that the focus
groups showed significant improvement in normalised learning gain values compared to
the control groups.
2.1. Research Samples
This study employed a purposive method to extract organic matter from acidic and
basic solutions. Participants in the study were students enrolled in the Department of
Chemistry at a University in Slovakia. The respondents consisted of 40 students, divided
into two groups: Group A, comprising 20 1st-year students from the academic years
2019/2020 and 2020/2021 (A1 = A2: 20 respondents), and Group B, comprising 20 1st-year
students from the academic years 2021/2022 and 2022/2023 (B1 = B2: 20 respondents).
Group A students took the online course Organic Chemistry Laboratory Exercise, while
Group B students took the full-time course. The students who participated in the study were
prospective chemistry teachers and took the Organic Chemistry I and Organic Chemistry
Seminar concurrently with the Organic Chemistry Laboratory Exercise course.
2.2. Experimental Part
Extraction with Acid and Alkaline Solutions
In this study, we present an example of an integrated laboratory exercise focused on
the extraction of an unknown mixture of organic compounds (benzoic acid,
β
-naphthol,
and p-nitroaniline) using acidic and basic solutions. The exercise consisted of the following
components: Motivation—a brief introductory input, analogies, and interesting tasks
T1a–1c
, which the students worked on after studying the topic from the literature, followed
by answering questions in the questionnaire. These sections contribute to the overall
understanding of the laboratory exercise and its educational significance.
Education method: The education method aspect is based on students’ active learning
in relation to a specific topic. The exercise aimed to engage students in understanding the
principles of extraction, preparation of solutions, and the factors influencing the course of
extraction. This method was designed to encourage students to apply theoretical knowl-
edge to practical scenarios.
Teacher competency represents the knowledge, understanding, skills, and intellectual
abilities of the teacher and students, which are essential for the successful implementation
of the exercise. Therefore, teacher education plays an important role in developing teachers’
knowledge and skills related to the use of technology in the classroom [19].
Analogies help students relate theoretical concepts to real-world applications, thus
making the learning process more engaging and relatable.
T1. The students were tasked with studying extraction from the chemistry literature, focusing on
the factors that affect extraction and how these factors influence the dissolution of substances in
each phase.
The exercise was divided into the following parts:
T1a. Aqueous and organic phases in the extraction and dissolution of substances in each phase.
T1b. Separation of selected organic substances from the mixture.
T1c. Occupational Health and Safety when working with chemicals (scalding and ingestion).
The exercise was designed to provide students with a comprehensive understanding
of the extraction process and its practical applications (e.g., coffee, tea, spices in foods,
oil infusions, citrus juices, extracts from herbs or flowers, juices, smoothies, fats, and oils)
while also emphasising the importance of safety precautions when working with chemicals.
T1a. Aqueous and organic phases in extraction and dissolution of substances in each phase.
It is based on the distribution of solutes between two immiscible liquid phases that are
in contact with each other. Briefly, SE is the two-phase distribution of the solute (X). The
separation funnel contains two layers of liquid. Generally, one is the aqueous phase (A)
and the other is the organic phase (B) [
20
]. After Xis split between Aand B, the extracted
Educ. Sci. 2024,14, 1051 7 of 19
analyte is recovered from phase Bfor further procedures or analysis. According to the
above theory, this partitioning can be described using the chemical equilibrium theory
as follows:
XA⇌XB(1)
If the concentration of Xis constant in one phase, it will also be constant in the other
phase. This relationship between the solute concentrations in the two phases leads to the
formulation of the Nernst distribution law. The distribution coefficient can be described as
KD=[X]B
[X]A
(2)
where [X]
A
and [X]
B
denote the concentration of Xin phases Aand Bat constant tem-
perature. It should be noted that the rate at which equilibrium is reached does not affect
the equilibrium constant. The K
D
result indicates the side of the equation in which the
concentration shifts to. If K
D
< 1, then a smaller concentration of Xis extracted from Ato B.
Suppose K
D
> 1, then a higher concentration of Xis extracted from Ato B. If K
D
= 1, then
the concentration of Xis the same in both the phases [21].
Another factor that will affect the distribution of Xin phases Aand Bis its solubility
in every phase. The ratio of the solubility of Xin the two phases is approximately equal to
the distribution coefficient, which means that:
KD=[X]B
[X]A
=SB
SA
(3)
where S
B
and S
A
are the solubilities of phases Aand B, and based on the aforementioned
information, the extract of the compound has to be extremely soluble in the organic phase
and sparingly soluble in the aqueous phase in order to be extracted successfully [22].
T1b Separation of selected organic substances from the mixture.
Some organic compounds can be separated from their mixtures using acidic or basic
aqueous solutions. These react with the organic compound to form its salt, which is soluble
in water and insoluble in the organic solvent. Carboxylic acids and phenols dissolved in
the organic phase can be separated by extraction with alkaline hydroxide solutions (5–10%
NaOH and KOH solutions). Salts or phenolates are formed, which are well soluble in
water. The organic solution of carboxylic acids and phenols must first be extracted with
a weaker base (such as NaHCO
3
), with which only the carboxylic acids react in order to
separate them. Similarly, dilute HCl is used to extract basic organic compounds. The base
compound (e.g., an amine) reacts with HCl to form the corresponding salt, which is soluble
in water [
23
,
24
]. The chemicals used for extraction with acidic and basic solutions were
the following: benzoic acid,
β
-naphthol, p-nitroaniline, HCl, KOH, NaHCO
3
, demi water,
and chloroform.
Chemicals were weighed using a balance for analytical purposes, the RADWAG Com-
pany AS 110/C/2 (Max. 110 g, Min. 10 mg, d = 0.1 mg, Libra s.r.o., Bratislava, Slovakia).
Workflow: students were given the task of separating an unknown mixture of organic
substances through extraction. This unknown mixture may have contained benzoic acid,
naphthalene-2-ol, and p-nitroaniline. A sample of unknown composition (0.75 g) was
dissolved in chloroform (20 mL) and extracted twice with a 20% HCl solution (2
×
6 mL).
After both extractions, the aqueous layers were combined in Beaker A and set aside. The
organic layer was extracted twice with a 10% NaHCO
3
solution (2
×
12 mL). After both
extractions, the aqueous layers were combined in Beaker B and set aside. Finally, the
organic layer was extracted with 10% NaOH solution (2
×
12 mL). The aqueous layers after
both extractions were combined in Beaker C and set aside.
The aqueous layers in beakers A-C were treated by neutralisation. The alkaline
aqueous solutions were neutralised with 20% HCl solution and the acidic aqueous solutions
were neutralised with 20% KOH solution. The pH values were tentatively determined
using a pH paper. The precipitates A-C formed were filtered and then dried, and the
Educ. Sci. 2024,14, 1051 8 of 19
extraction yield was determined. The organic layer was dried by standing over anhydrous
Na2SO4(10–15 min) and was removed by filtration (Scheme 2).
Educ. Sci. 2024, 14, x FOR PEER REVIEW 8 of 19
water. The organic solution of carboxylic acids and phenols must first be extracted with a
weaker base (such as NaHCO
3
), with which only the carboxylic acids react in order to
separate them. Similarly, dilute HCl is used to extract basic organic compounds. The base
compound (e.g., an amine) reacts with HCl to form the corresponding salt, which is solu-
ble in water [23,24]. The chemicals used for extraction with acidic and basic solutions were
the following: benzoic acid, β-naphthol, p-nitroaniline, HCl, KOH, NaHCO
3
, demi water,
and chloroform.
Chemicals were weighed using a balance for analytical purposes, the RADWAG
Company AS 110/C/2 (Max. 110 g, Min. 10 mg, d = 0.1 mg, Libra s.r.o., Bratislava, Slo-
vakia).
Workflow: students were given the task of separating an unknown mixture of or-
ganic substances through extraction. This unknown mixture may have contained benzoic
acid, naphthalene-2-ol, and p-nitroaniline. A sample of unknown composition (0.75 g) was
dissolved in chloroform (20 mL) and extracted twice with a 20% HCl solution (2 × 6 mL).
After both extractions, the aqueous layers were combined in Beaker A and set aside. The
organic layer was extracted twice with a 10% NaHCO
3
solution (2 × 12 mL). After both
extractions, the aqueous layers were combined in Beaker B and set aside. Finally, the or-
ganic layer was extracted with 10% NaOH solution (2 × 12 mL). The aqueous layers after
both extractions were combined in Beaker C and set aside.
The aqueous layers in beakers A-C were treated by neutralisation. The alkaline aque-
ous solutions were neutralised with 20% HCl solution and the acidic aqueous solutions
were neutralised with 20% KOH solution. The pH values were tentatively determined us-
ing a pH paper. The precipitates A-C formed were filtered and then dried, and the extrac-
tion yield was determined. The organic layer was dried by standing over anhydrous
Na
2
SO
4
(10–15 min) and was removed by filtration (Scheme 2).
Scheme 2. Acid-Base extractions.
T1c Occupational Health and Safety when working with chemicals
Occupational Health and Safety (OHS) are critical for working with chemicals [25,26].
This encompasses the importance of teaching laboratory safety [27], minimising exposure
risks [28], and addressing potential hazards [29]. Students are briefed on OHS in chemis-
try laboratories, covering safe chemical handling and the use of personal protective equip-
ment (PPE). According to Özbakir [26], Pryor et al. [30], and Rahmi and Ramdhan [31],
Scheme 2. Acid-Base extractions.
T1c Occupational Health and Safety when working with chemicals
Occupational Health and Safety (OHS) are critical for working with chemicals [
25
,
26
].
This encompasses the importance of teaching laboratory safety [
27
], minimising exposure
risks [
28
], and addressing potential hazards [
29
]. Students are briefed on OHS in chemistry
laboratories, covering safe chemical handling and the use of personal protective equipment
(PPE). According to Özbakir [
26
], Pryor et al. [
30
], and Rahmi and Ramdhan [
31
], the
implementation of an OHS management system aims to create a safe work environment,
emphasising safe work principles such as proper handling, storage, and waste disposal.
Specific safety precautions for chemicals used in the experiment, such as benzoic acid,
beta-naphthol, p-nitroaniline, hydrochloric acid, potassium hydroxide, NaHCO
3
, and chlo-
roform, were highlighted to minimise health risks and ensure safe handling and disposal.
The following factors affecting the effectiveness of OHS implementation were included
in the safe work principles: use, chemical and physical properties, hazardous reactions,
physiological properties and health hazards, ventilation, proper handling, storage, first
aid for ingestion, scalding and inhalation, waste and its disposal, and firefighting of
chemical fires.
The students were warned about the following for the chemicals used:
Benzoic acid (benzoic acid) care should be taken when handling and avoid inhalation
of aerosol or skin contact [
32
,
33
]. This includes proper methods of mixing, dissolving, or
handling the substance. Benzoic acid should be stored in well-closed containers, separate
from other chemicals, and protected from direct sunlight and high temperatures [34].
Beta-naphthol (beta-naphthol, para-nitroaniline) protects against some dangerous
reactions such as oxidation, reactions with acids, oxidising agents and metals. Safety
measures involve using appropriate personal protective equipment (PPE) when working in
well-ventilated areas [
35
]. The physiological and health risks are skin, eye and respiratory
irritation and toxic effects if it enters the body (it causes nausea, vomiting, headache,
dizziness and, in more severe cases, can cause liver and kidney damage).
P-nitroaniline (para-nitroaniline) is toxic and can have negative health effects such as
dermal exposure inhalation, ocular exposure, ingestion, and chronic exposure [36]. Safety
precautions and the use of PPE are required when handling this substance. It is important
to emphasise that the degree of toxicity and health risk depends on specific exposure
Educ. Sci. 2024,14, 1051 9 of 19
conditions such as the duration, intensity and route of contact with para-nitroaniline. Para-
nitroaniline (4-nitroaniline) can undergo a variety of chemical reactions due to the presence
of a nitro group (NO
2
) and an aromatic nucleus, such as reduction, acylation, nitration,
diazotisation and copulation, oxidation, substitution reactions [35,37].
Hydrochloric acid (HCl) is a strong inorganic acid that poses risks such as skin and
eye irritation, respiratory issues, and ingestion hazards [
38
,
39
]. Safety precautions in-
clude avoiding skin and eye contact, using protective equipment, and working in well-
ventilated areas [
39
]. Proper storage, labelling, and handling of HCl [
35
,
40
] are essential to
mi-nimise risks.
Potassium hydroxide (KOH) is a strong base that can cause skin, respiratory, and eye
irritation [
35
], and it can react with acids to form salts and water. Safety measures involve
using appropriate personal protective equipment (PPE), working in well-ventilated areas,
and avoiding contact with sensitive metals such as aluminium or zinc.
Sodium bicarbonate (NaHCO
3
) is a weak base that can react with acids to release car-
bon dioxide gas, causing bubbling reactions. Safety precautions include wearing protective
gear, minimising inhalation of the powder, and storing NaHCO
3
in a dry, tightly sealed
container. By providing this information, you can emphasise the importance of adhering
to safety protocols when working with these chemicals and highlight the potential risks
associated with them.
Chloroform (carbon tetrachloride, CCl
4
) is known for its toxicity and potentially
hazardous effects on human health (respiratory system, CNS, liver). Chloroform has been
classified as a probable human carcinogen. It may have a negative effect on reproductive
and developmental capacity. Chloroform is also an environmental concern [
35
]. It is often
found in wastewater and can contribute to the formation of chlorinated organic compounds
that can be toxic to aquatic organisms. It is also important to follow measures to reduce
exposure to chloroform when working with it, such as working in well-ventilated areas
and using protective equipment such as respirators and gloves [35].
2.3. Data Collection and Analysis
The data of the study was collected from the results of the questionnaire, which
consisted of 7 questions and conducting interviews with each respondent while also having
them actively participate in the exercise. The closed-ended questions (3) were related to the
theoretical knowledge acquired by the students and its application. The semi-open (3) and
open-ended (1) questions gave the respondents the opportunity to express their opinions
or further insights and comments on the issues under study. They focused on problem
solving and logical thinking. Their role was to help the respondents understand the
principle and search for answers (to think more deeply about the topic of extraction). In the
questionnaire, respondents answered the questions (Section 2.3.1). The items also focused
on the knowledge of the respondents-pre-service chemistry teachers, after the laboratory
exercise. They were oriented to the conditions affecting extraction, how they illustrate
extraction in the classroom material, and their understanding of the extraction method,
which involves extracting substances using acidic and basic aqueous solutions. The section
also delves into the safety precautions and the importance of occupational health and
safety when working with chemicals, which is crucial for laboratory exercises. It provides a
thorough understanding of the safety measures and the potential hazards associated with
the chemicals used in the experiment. In addition, an open-ended questionnaire covered
the students’ knowledge prior to the laboratory exercise regarding the acid-base extraction
of a mixture of organic compounds. In the preparatory phase, interviews were conducted
with students regarding the extraction method, conditions, and applications, as well as to
confirm the results from the questionnaire. The results obtained from the interviews were
used as a basis to validate the questionnaire data.
Educ. Sci. 2024,14, 1051 10 of 19
2.3.1. Questions to Be Answered in the Experiment
1. Define the principle of extraction of an unknown mixture of substances with acidic
and basic aqueous solutions.
...........................................................................................................................................................
..............................................................................................................................................................
2. After the equilibrium is established, two phases are formed in the separating funnel.
On what basis do you determine which phase is aqueous and which phase is organic?
(a) phase densities
(b) the characteristics (sensory and olfactory) of the solvents
(c) the volumes of solvents used
(d) other..............................................................................................
3. In what possible ways can emulsions that impair/prevent separation of the layers
in the extraction funnel be removed?
(a) disruption of the emulsion
(b) desalting
(c) swirling of liquids
(d) stagnation
4. How would you separate a mixture of the substances benzoic acid,
β
-naphthol, and
4-nitroaniline? Aqueous solutions (20% HCl, 10% NaHCO3, 10% NaOH, 20% KOH) are
available. Write the corresponding equations, including the reversible reactions.
Write ways to separate.........................................................................................
List the equations..........................................................................................................
5. Identify at least 3 types of compounds that can be separated by extraction with
acidic and basic solutions, i.e., for which chemicals is this method suitable:
(a) Inorganic compounds
(b) Dyes and pigments
(c) Ionic compounds with low solubility
(d) Polymeric compounds
(e) Organic acids
(f) Alkaline substances
(g) Compounds with very low concentrations
6. What safety precautions should be observed when working with acidic or basic solu-
tions during extraction? This question could highlight the importance of safety precautions
when handling chemicals. Write a minimum of 4.
...........................................................................................................................................................
...........................................................................................................................................................
............................................................................................................................................
7. Indicate (write) what knowledge you have gained from this laboratory exercise?
(not rated)
...........................................................................................................................................................
.................................................................................................................................................
3. Results and Discussion
Students began the experiment by investigating the fundamental concepts of density
and solubility. The instructor provided a minimal pre-laboratory discussion to facilitate
students making observations and conclusions about these extraction principles.
During the exercise, the respondents worked in pairs to solve the problem together
(group activity). As per Carroll et al. [
41
], learning communities can provide space and
structure for people to share common goals and learn together. In the field of education,
goals are personal characteristics to promote in learners (children, pupils, students, adults,
etc.) [
42
]. Learning communities promote collective learning and complex problem solving.
They explored the specific task they were given in the form of an experiment (indepen-
dent exploration). In this way, the respondents actively focused on finding answers and
Educ. Sci. 2024,14, 1051 11 of 19
obtaining concrete results. Groups of people who share the goal of learning are considered
from different perspectives [
43
]. According to reports by Piccinno et al. [
44
], “the student
perception to be strongly influenced by whether the activity is offered as an obligation or
as a voluntary option”.
Respondents were given an unfamiliar mixture of substances at the beginning of the
laboratory exercise. This mixture consisted of benzoic acid,
β
-naphthol, and p-nitroaniline.
In reality, they had prepared a mixture of benzoic acid and
β
-naphthol in a 1:1 ratio. After
dissolving the unknown mixture of substances in chloroform, they observed a brown
colouration of the solution. After adding a 20% aqueous HCl solution and subsequent
extraction, the students observed the formation of two phases. Dilute hydrochloric acid
was used to extract basic organic compounds. In our case, it was p-nitroaniline. In the
second step, a 10% aqueous solution of NaHCO
3
was added to the organic phase. Sodium
bicarbonate is used to obtain carboxylic acids, such as benzoic acid. Finally, extraction was
carried out with a 10% aqueous NaOH solution. NaOH solution can be used to extract
β-naphthol from a mixture of compounds.
Each extraction was performed two times, as it is known that repeated (multiple)
extractions are more efficient than a single extraction [
45
,
46
]. As reported by Chen et al. [
45
]
(2023) and Zhao et al. [
47
], the peak was reached during the third extraction (28.88%). The
results showed that the yield was significantly affected by the number of extractions, as
well as the interaction between the extraction time and number of extractions [
45
,
46
]. The
extractions of each compound from the mixture are shown in Figure 1.
Educ. Sci. 2024, 14, x FOR PEER REVIEW 12 of 19
(a) (b)
(c) (d)
Figure 1. (a) A mixture of substances dissolved in 20 mL of chloroform; (b) Extraction of the mix-
ture using 2 × 6 mL of 20% HCl solution; (c) Extraction of the mixture using 2 × 12 mL of 10% Na-
HCO3 solution; (d) Extraction of the mixture using 2 × 6 mL of 10% NaOH solution.
The aqueous solutions obtained after extraction were placed in beakers labelled 1–3
(Figure 2). Neutralisation with aqueous solutions of 20% HCl and KOH was carried out.
After neutralisation, the starting materials were recovered from the salts. This allowed the
students to identify that they had only benzoic acid and β-naphthol present in their mix-
ture. The compound p-nitroaniline was not present in the mixture of unknown substances.
Analysing the results: during the exercises, students can analyse the results obtained,
compare them with theoretical assumptions, and discuss the reasons for deviations be-
tween expected and actual results.
In terms of active learning, the following applies:
− Assigning problems or unusual situations that require chemical knowledge to solve
can promote critical thinking and application of theoretical knowledge (working
with problems).
− At the end of the experiment, a discussion was held on what the students had learned,
what problems had arisen, and how things could have been conducted differently
(reflection with discussion).
− Students presented their results and observations to their classmates, which encour-
aged communication and feedback (sharing results). The above statement agrees
with the views of many authors [41,48,49].
Figure 1. (a) A mixture of substances dissolved in 20 mL of chloroform; (b) Extraction of the mixture
using 2
×
6 mL of 20% HCl solution; (c) Extraction of the mixture using 2
×
12 mL of 10% NaHCO
3
solution; (d) Extraction of the mixture using 2 ×6 mL of 10% NaOH solution.
Educ. Sci. 2024,14, 1051 12 of 19
The aqueous solutions obtained after extraction were placed in beakers labelled 1–3
(Figure 2). Neutralisation with aqueous solutions of 20% HCl and KOH was carried out.
After eutralization, the starting materials were recovered from the salts. This allowed the
students to identify that they had only benzoic acid and
β
-naphthol present in their mixture.
The compound p-nitroaniline was not present in the mixture of unknown substances.
Educ. Sci. 2024, 14, x FOR PEER REVIEW 13 of 19
(a) (b)
Figure 2. (a) Organic and aqueous phases after acid-base extraction; (b) aqueous phases after neu-
tralisation using 20% HCl solution and 20% KOH solution
Results of the Questionnaire (2019–2023)
Before commencing the laboratory exercise, pre-service chemistry teachers were pro-
vided with a comprehensive handout covering the general topic of extraction acid-base
extraction and an assignment to practice in class to enhance their practical skills. The sub-
ject of acid-base reactions has been thoroughly addressed in seminars, which are part of
the Organic Chemistry course or are offered as a separate course under the title Organic
Chemistry Seminar. Our objective was to assess how students connected their acquired
knowledge of “Acid-base reactions” with the practical exercise titled “Extraction of an un-
known mixture of substances by acidic and basic aqueous solutions”. In this context, the
enhancement of knowledge of organic chemistry is a pivotal aspect of the education of
future teachers. As Conte et al. [50] assert, the implementation of more practical activities
in schools leads to an increase in social-emotional competencies.
Experiment—Question 1: Students were tasked with defining the principle of extract-
ing an unknown mixture of substances using acidic and basic aqueous solutions. This
principle was correctly defined in all cases, with both groups A and B providing accurate
responses.
Experiment—Question 2: Upon the establishment of equilibrium, two phases were
formed in the separating funnel. Students were required to identify the basis for deter-
mining which phase was aqueous or organic. They were instructed to select all correct
answers from the options provided and possibly add more answers. Responses included
considerations of the different densities of the phases as well as the characteristics of the
solvents used. In cases where the densities of the solvents were unknown, students also
reported considerations, such as the volumes of the solvents used in the extraction pro-
cess.
Educational institutions and educators often need to deal with a large number of
documents, including course materials, student assignments, teaching materials, and so
on [51]. As Kelley [52] notes, much of chemistry education in the period associated with
the teaching of COVID-19 has been replaced by online alternatives, and this is also the
case for laboratory exercises. This fact was the reason 80% of Group A respondents an-
swered incorrectly. According to Barton et al. [53], the sudden change to online teaching
in the academic years 2019/2020 and 2020/2021 primarily negatively impacted practical
laboratory teaching. This was pointed out by Villegas-Ch. et al. [14], and Shukla and
Verma [54], the problem with the online educational model is that although it is intended
to adapt to the needs of students both in time and in education, in reality, this does not
happen, and low academic effectiveness. Group B respondents answered 20% of the ques-
tions incorrectly. We agree with the results found by Simmons and Mistry [55] that in-
person laboratories are more appropriate in terms of acquiring laboratory skills and ap-
plying knowledge therein. Moreover, Carroll et al. [41] describe that the learning commu-
Figure 2. (a) Organic and aqueous phases after acid-base extraction; (b) aqueous phases after
neutralisation using 20% HCl solution and 20% KOH solution.
Analysing the results: during the exercises, students can analyse the results obtained,
compare them with theoretical assumptions, and discuss the reasons for deviations between
expected and actual results.
In terms of active learning, the following applies:
−
Assigning problems or unusual situations that require chemical knowledge to solve
can promote critical thinking and application of theoretical knowledge (working with
problems).
−
At the end of the experiment, a discussion was held on what the students had learned,
what problems had arisen, and how things could have been conducted differently (reflection
with discussion).
−
Students presented their results and observations to their classmates, which encouraged
communication and feedback (sharing results). The above statement agrees with the views
of many authors [41,48,49].
Results of the Questionnaire (2019–2023)
Before commencing the laboratory exercise, pre-service chemistry teachers were pro-
vided with a comprehensive handout covering the general topic of extraction acid-base
extraction and an assignment to practice in class to enhance their practical skills. The
subject of acid-base reactions has been thoroughly addressed in seminars, which are part of
the Organic Chemistry course or are offered as a separate course under the title Organic
Chemistry Seminar. Our objective was to assess how students connected their acquired
knowledge of “Acid-base reactions” with the practical exercise titled “Extraction of an
unknown mixture of substances by acidic and basic aqueous solutions”. In this context,
the enhancement of knowledge of organic chemistry is a pivotal aspect of the education of
future teachers. As Conte et al. [
50
] assert, the implementation of more practical activities
in schools leads to an increase in social-emotional competencies.
Experiment—Question 1: Students were tasked with defining the principle of ex-
tracting an unknown mixture of substances using acidic and basic aqueous solutions.
This principle was correctly defined in all cases, with both groups A and B providing
accurate responses.
Experiment—Question 2: Upon the establishment of equilibrium, two phases were
formed in the separating funnel. Students were required to identify the basis for deter-
mining which phase was aqueous or organic. They were instructed to select all correct
Educ. Sci. 2024,14, 1051 13 of 19
answers from the options provided and possibly add more answers. Responses included
considerations of the different densities of the phases as well as the characteristics of the
solvents used. In cases where the densities of the solvents were unknown, students also
reported considerations, such as the volumes of the solvents used in the extraction process.
Educational institutions and educators often need to deal with a large number of
documents, including course materials, student assignments, teaching materials, and
so on [
51
]. As Kelley [
52
] notes, much of chemistry education in the period associated
with the teaching of COVID-19 has been replaced by online alternatives, and this is also
the case for laboratory exercises. This fact was the reason 80% of Group A respondents
answered incorrectly. According to Barton et al. [
53
], the sudden change to online teaching
in the academic years 2019/2020 and 2020/2021 primarily negatively impacted practical
laboratory teaching. This was pointed out by Villegas-Ch. et al. [
14
], and Shukla and
Verma [
54
], the problem with the online educational model is that although it is intended to
adapt to the needs of students both in time and in education, in reality, this does not happen,
and low academic effectiveness. Group B respondents answered 20% of the questions
incorrectly. We agree with the results found by Simmons and Mistry [
55
] that in-person
laboratories are more appropriate in terms of acquiring laboratory skills and applying
knowledge therein. Moreover, Carroll et al. [
41
] describe that the learning communities
(groups) are important in how they bring together teachers, students, etc., to support
one another in their learning through shared knowledge and experience.
Zhang et al. [51]
state that the development and application of technology will bring about smarter and
more efficient methods of educational management and teaching, leading to an overall
improvement in the quality of educational delivery and outcomes, but this is not the case
for the acquisition of laboratory skills.
Experiment—Question 3: In Question 3 of the experiment, students were asked about
methods to remove emulsions formed during extraction. The most common responses
included breaking of the emulsion using a glass rod or desalting. Few students mentioned
simple swirling of liquids in the separating funnel or extended standing time. It was noted
that both Group A and Group B respondents had performed basic operations prior to the
exercise. The lack of mastery of these basic skills was evident, as only 10% of Group A
respondents and 30% of Group B respondents answered correctly.
Experiment—Question 4: In Question 4, students were instructed to use the provided
aqueous solutions (20% HCl, 10% NaHCO
3
, 10% NaOH, 20% KOH) to separate a combi-
nation of benzoic acid,
β
-naphthol, and 4-nitroaniline. The students demonstrated their
ability to comprehend the provided literature, with 60% of Group A and 80% of Group B
respondents answering correctly and writing appropriate equations including reversible
reactions (Scheme 3).
Educ. Sci. 2024, 14, x FOR PEER REVIEW 14 of 19
nities (groups) are important in how they bring together teachers, students, etc., to sup-
port one another in their learning through shared knowledge and experience. Zhang et al.
[51] state that the development and application of technology will bring about smarter
and more efficient methods of educational management and teaching, leading to an over-
all improvement in the quality of educational delivery and outcomes, but this is not the
case for the acquisition of laboratory skills.
Experiment—Question 3: In Question 3 of the experiment, students were asked about
methods to remove emulsions formed during extraction. The most common responses
included breaking of the emulsion using a glass rod or desalting. Few students mentioned
simple swirling of liquids in the separating funnel or extended standing time. It was noted
that both Group A and Group B respondents had performed basic operations prior to the
exercise. The lack of mastery of these basic skills was evident, as only 10% of Group A
respondents and 30% of Group B respondents answered correctly.
Experiment—Question 4: In Question 4, students were instructed to use the provided
aqueous solutions (20% HCl, 10% NaHCO3, 10% NaOH, 20% KOH) to separate a combi-
nation of benzoic acid, β-naphthol, and 4-nitroaniline. The students demonstrated their
ability to comprehend the provided literature, with 60% of Group A and 80% of Group B
respondents answering correctly and writing appropriate equations including reversible
reactions (Scheme 3).
Scheme 3. Chemical equations.
Experiment—Question 5: In Question 5, students were asked to identify three types
of compounds suitable for separation by extraction with acidic and basic solutions. How-
ever, only 10% of Group A and 20% of Group B respondents answered correctly, indicat-
ing an insufficient application of theoretical knowledge in both groups.
Experiment—Question 6: In Question 6 of the experiment, participants were tasked
with outlining a minimum of four safety measures to adhere to when handling acidic or
basic solutions during extraction. This question aimed to underscore the critical nature of
safety protocols when working with chemicals, particularly emphasising the need for
heightened precautions when dealing with acidic and basic solutions due to their poten-
tial health and safety hazards. Key safety measures to be observed during the handling of
acid and alkaline solutions in vapour extraction include the use of protective work gear,
working in well-ventilated areas, careful handling, proper storage and labelling of chem-
icals, appropriate management of acid and alkaline substances, adherence to preparation
procedures, familiarity with accident protocols, cautious waste handling, and correct di-
lution of solutions during disposal. It is imperative that respondents adhere to these pre-
cautions when working with acidic and alkaline solutions to mitigate the risk of accidents
and injuries. Respondents must receive adequate training and be well-informed about all
aspects of safely managing these chemicals. The ratio of correct answers was notably
Scheme 3. Chemical equations.
Educ. Sci. 2024,14, 1051 14 of 19
Experiment—Question 5: In Question 5, students were asked to identify three types of
compounds suitable for separation by extraction with acidic and basic solutions. However,
only 10% of Group A and 20% of Group B respondents answered correctly, indicating an
insufficient application of theoretical knowledge in both groups.
Experiment—Question 6: In Question 6 of the experiment, participants were tasked
with outlining a minimum of four safety measures to adhere to when handling acidic or
basic solutions during extraction. This question aimed to underscore the critical nature
of safety protocols when working with chemicals, particularly emphasising the need for
heightened precautions when dealing with acidic and basic solutions due to their potential
health and safety hazards. Key safety measures to be observed during the handling
of acid and alkaline solutions in vapour extraction include the use of protective work
gear, working in well-ventilated areas, careful handling, proper storage and labelling
of chemicals, appropriate management of acid and alkaline substances, adherence to
preparation procedures, familiarity with accident protocols, cautious waste handling, and
correct dilution of solutions during disposal. It is imperative that respondents adhere
to these precautions when working with acidic and alkaline solutions to mitigate the
risk of accidents and injuries. Respondents must receive adequate training and be well-
informed about all aspects of safely managing these chemicals. The ratio of correct answers
was notably higher in favour of Group B respondents, affirming the significance of the
practical exercise.
Experiment—Question 7: When asked what knowledge the respondents gained from
the laboratory exercise on extraction, they answered that they did:
−
practical skills (handling laboratory equipment, working with tools and instruments)—it
helped them learn how to plan, conduct and evaluate experiments,
−
they learned how to collect data and record observations (a key element of scientific
research),
−validate the theoretical knowledge they have acquired and link it to practice [56]),
−
they could also use knowledge from other subjects (Chemical calculations, Statistical
processing of experimental data), analyse them, apply statistical methods, and draw con-
clusions from the results of experiments. As stated by Hsu [
57
], data science education
from computer science and statistics departments is becoming more widely included in
general education to enhance interdisciplinary and composite competencies,
−laboratory exercises included teaching safety procedures and proper handling of chemicals,
−working in a team, which is an important aspect of scientific work,
−critical thinking and evaluation of evidence are also part of the laboratory exercise.
When asked what knowledge the respondents gained from the laboratory exercise, the
students answered that they found the task very interesting in terms of gaining practical
skills and linking theoretical knowledge with practice. It also provided them with a
valuable reference for potentially streamlining the integration of multiple disciplines within
a laboratory exercise, while providing flexibility for students with different chemistry
education backgrounds. Before practising the task, students were not aware that it was
possible to separate an organic compound from a mixture using extraction.
They also stated that, before practising the task, the students were unaware that it was
possible to separate an organic compound from a mixture using extraction. At the same
time, they did not understand the connection between the experimental task focusing on
extraction with acid and base solutions in the laboratory exercise and the acid-base reactions
taught in the seminars, i.e., the respondents were not aware of the connection between these
topics. Consequently, they stressed that, after practising and consulting the tutor on the task,
they understood the connections related to the extraction of organic compounds with acidic
and basic solutions. According to Zhang et al. [
51
], traditional education systems face many
challenges, one of which is the management and utilisation of educational resources. From
the answers given for the item, it is clear that active participation in laboratory exercises
gives the respondents the opportunity to acquire the necessary knowledge and skills.
Educ. Sci. 2024,14, 1051 15 of 19
For online teaching (2019/2020, 2020/2021), the cancellation of lab work will affect not
only students’ knowledge, but also the acquisition of lab skills (Table 1). When evaluating
the responses from the pandemic period, it is important to reflect on its medium to long-
term impact, as reported by Simmons and Mistry [
55
]. It is important to point out that
extraction with acid and base solutions in the laboratory exercise prompted extensive
discussion of the chemical principles underlying the method, as reported by Ambruso
and Riley [58].
Table 1. Verifying the Active Learning model.
Questions 2019–2021
(A Group: 20 Respondents)
2021–2023
(B Group: 20 Respondents)
True (Number of
Respondents)
False (Number of
Respondents)
True (Number of
Respondents)
False (Number of
Respondents)
1. Principle of extraction of an
unknown mixture 20 0 20 0
2. What determines the aqueous
and organic phases once
equilibrium is reached?
4 16 16 4
3. What are the ways to remove
the emulsion? 2 18 6 14
4. Separating a mixture of
substances: benzoic acid,
β
-naphthol, 4-nitroaniline with the
help of HCl, NaHCO3, NaOH,
KOH and their reactions.
12 8 16 4
5. Identify three types of
compounds that can be separated
by extraction with acidic and
basic solutions.
2 18 4 16
6. OHS when working with acidic
or basic solutions during
extraction.
2 18 15 5
7. Knowledge acquired. It has not been evaluated. It has not been evaluated.
The results (Table 1) indicate that Group B (2021–2023) had a higher mean of correct
responses and lower variability compared to Group A (2019–2021). Analysing the results
for each question, we found that there were large differences in the number of correct
answers given by respondents for questions 2, 3, 4, 5 and 6. Calculated p-values from t-tests
for each question showed that these questions had extremely low p-values (for questions 2,
3, 4, 6, p= 0.00; for question 5, p= 0.01). This indicates a very strong statistical significance
of the differences between online and face-to-face groups. The above results support the
claim that face-to-face learning in the lab has a significantly positive effect on student
performance compared to the online group. For question 1, the p-value = 1.0, indicating
that there was no difference between the groups in the number of correct answers to this
question because all students answered correctly. Based on the results of the t-test, we can
argue that the face-to-face laboratory exercise significantly improves students’ knowledge
and skills compared to the online study.
The Wilcoxon test confirmed the differences between online and face-to-face instruc-
tion. For question 1 (p= 1.00), there was no difference between the online and face-to-face
groups, as all students answered correctly. The p-values from the Wilcoxon test confirmed
p= 0.00 for questions 2, 3, 4, and 6, and p= 0.01 for question 6. This means that face-to-face
study has a positive effect on students’ performance in these questions. The results of
Educ. Sci. 2024,14, 1051 16 of 19
the Wilcoxon test supported the conclusion that practical learning in the laboratory has a
significant effect on student performance.
When comparing online and face-to-face active learning in the context of a laboratory,
online and face-to-face approaches have advantages and disadvantages that can affect
the effectiveness of learning. The key factors are face-to-face contact with the educator,
hands-on experience that is important for learning, flexibility, and learning effectiveness.
Online and face-to-face methods of active learning have their own specificities, and the most
appropriate choice depends on the type of laboratory exercise. Consequently, available
resources and student preferences also play an important role. Face-to-face lab exercises
offer a more authentic hands-on experience than online exercises. Online laboratory
exercises can provide greater flexibility and accessibility. Both forms can be effective if
implemented properly and if students’ needs and preferences are considered.
4. Conclusions
In conclusion, integrating an active learning approach into chemistry laboratory exer-
cises can establish a dynamic, engaging, and stimulating learning environment, enabling
students to develop a deeper understanding of chemistry and its practical applications.
This study makes a valuable contribution to current knowledge by addressing the problem
of defining the specific content of extraction and its application. The respondents in this
study were introduced to the principles of occupational health and safety, emphasising the
importance of following these principles during extraction with acidic and basic aqueous
solutions. The chemical experiment allowed respondents to practice the practical aspects of
extraction and acquire essential laboratory skills. This study underscored the significance
of the extraction method for acidic and basic solutions, offering valuable insights for future
research in this area. Subsequent research could explore the impact of other factors, such
as changes in the solvent pH, temperature, and pressure, on the efficiency of organic com-
pound extraction, potentially leading to the development of more effective and sustainable
extraction methods. Overall, this study has significantly contributed to a deeper under-
standing of the extraction principle. Following the experiment, the students completed
a questionnaire to assess the knowledge they gained from practising the extraction of an
unknown mixture of organic compounds using acidic and basic aqueous solutions. The
findings revealed that the students initially struggled to connect their theoretical knowledge
with practical applications. However, after engaging in a hands-on task and consulting
with the teacher, they were able to bridge this gap and apply their knowledge effectively
over time. This article provides an overview of this type of experiment and identifies its
characteristics to guide chemistry teachers in utilising them more effectively. Therefore, it
is crucial to conduct as many experiments as possible during chemistry teaching.
Author Contributions: Conceptualisation, J.J. and M.F.; methodology, J.J. and M.F.; formal analy-
sis, J.J. and M.F.; resources, J.J. and M.F.; data curation, M.F. writing—original draft preparation,
J.J., V.S. and M.F.; writing—review and editing, M.F. and J.J.; visualisation, J.J.; supervision, M.F.;
project administration J.J. and M.F. All authors have read and agreed to the published version of
the manuscript.
Funding: This work has been supported by the UGA Grant No. VIII/9/2023.
Institutional Review Board Statement: The study was conducted in accordance with the Declaration
of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) of Constantine
the Philosopher University in Nitra (protocol code UKF/872/2024/191013:002; 12.08.2024) for studies
involving humans.
Informed Consent Statement: Informed consent was obtained from all subjects involved in
the study
.
Data Availability Statement: The original contributions presented in the study are included in the
article, further inquiries can be directed to the corresponding authors.
Conflicts of Interest: The authors declare no conflict of interest.
Educ. Sci. 2024,14, 1051 17 of 19
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