Liliasari
Department of Chemistry Education
Faculty of Mathematics and Science Education
UNIVERSITAS PENDIDIKAN INDONESIA
2018
4.0 IR ERA:
accelerate industrialization and modernization
Based on 3 area :
Digital : big data, artificial intelligence
Biotechnology: new medicine, chemistry &
biotechnology material , renewable energy
Physics : next-generation robot, new
material, nanotechnology
Educator should mastery on problem solving,
critical thinking & creativity in chemistry
Multiple representation:
Representational competence associate with:
meaningfull technique of problem solving & explaining phenomenon
o convey much information
o language of chemical science
o used to communicate, develop thinking skills &
process skills
o enhance chemical content knowledge
CHEMISTRY EDUCATION IN 4 IR
Tabel
More complex learning: combine skills and very fast development of chemistry content vs real life
Developed higher order thinking skills
Learning process focus on: relating structure and properties of matter based on application needed using modeling skills
Modeling skills as students’ creative idea of
targets molecular developed in 4 IR era
Modeling skills: connecting analog & target
Analog: symbolic representation
Target : macroscopic phenomena & submicroscopic proces
model of chemical structure:
- simplification of chemical phenomena or process - focuss on specific aspects/ components of a system - ideas, concepts, objects, events, process, compositions - represents in physical and computational form
- imagine and visualize in students’ cognitive structure
Modeling skills can explain and predict the nature of concepts
Molecular structure demands a high spatial ability
Inorganic Chemistry: structure & properties of inorganic compounds describe broadly included real phenomena context and could be predict in real life using technology (the product are not found in nature)
Organic Chemistry: explain structure, properties, energy, stability, product regioselectivity,
intermediate, and mechanism of reaction; therefore as computer assistence in synthesis design (the
product is already found in nature by natural
product)
Objective : to develop HOTS using modeling skills for improving students’ competitiveness in 4 IR era
Methods : mixed methods embeded experimental model
Participants :
23 pre-service chemistry teachers (Inorganic Chemistry course in Bandung)
16 pre-service chemistry teachers (Organic Chemistry couse in Jayapura- Papua)
Instruments : students worksheet of Inorganic Chemistry Students Spartan V6 software of Organic Chemistry
INORGANIC CHEMISTRY : Average percentages of pretest, post-test, and n-gain scores of students on each modeling skills.
Sub-modeling 1: Create structure model material
Transform formula to structure or vice versa
If the information students selected interpreted incorrectly, the model character created will be wrong
Sub-modeling 2: use model to explain properties/
fenomena
Analysis structure more appropriate done to solve problem
If students do not analysis the structure, they will not solve the problem of properties/fenomena
Differeces of three sub- modeling in
Inorganic Chemistry (1)
Sub-modeling 3: to use structural model to evaluate or predict the properties of compounds
Conductivity of material to find the way to change conductivity
Students gave 2 opposite answers : graphite & polimer cannot conduct electricity, but they are conductors (?)
Graphite only have delocalize electron on of the sheets, in poly-acetylene no electron delocalized
If graphite convert to graphene that have single layer of atoms, it will has a very fast electron mobility of free phi electron
In poly-acetylene coductivity by doping:halogen doping (oxidation) p-doping and alkali metal doping(reduction) called n-doping
Modeling an alloy type based on metallic atom and
structure character
1. Copper metal can substitute for silver metal in a CCP structure. Both elements are formed in CCP unit cells, so a little disruption in Ag metal lattice should result from incorporating Cu atoms, which are they have a nearly same size.
2. Copper atoms are too big, to fit into the octahedral site in the lattice of silver atoms.
Thus, Cu-Ag alloy is a substitution alloy no an interstitial.
3. The guideline for two metals forming a substitution alloy is their atomic radii. To form a substitution alloy, the difference of their radii should be not more than 15%. The radii of Ag and Cu differ by only 11%, so we would expect copper and silver metal to form a substitution alloy.
4. Moreover, copper and silver atoms are in the same group in the periodic table and have the same crystal structures.
Sub-Modeling skill 1
Modeling a chemical
structure of substance or material
Sub-Modeling skill 1
Modeling process of
semiconductor conductivity
Sub-Modeling skill 1
Using structure model to explain properties in the metallic crystal (Ductility)
1. In the case of the cubic closed structured metal crystal, there are glide planes within the atomic layers in all directions, thus the mechanical attack can be repelled from many directions through the movement between atomic layers.
The elementary cube itself allows the movement of smooth triangular layers in four directions, i.e. perpendicular to the four diagonal spaces.
2. In comparison, the hexagonally closed structured metal crystal has only one direction of the triangular layer in the hexagonal unit cell. These metals are not very ductile and crumble to dust when force is applied
Sub-Modeling skill 2
Using structure model to explain properties in the metallic crystal (Ductility)
Sub-Modeling skill 2
Using structure model to predict properties on the material
1. Based on the structure of graphite and polyacetylene, predict how the conductivity of the two materials!
2. As the properties of the graphite or polyacetylene conductivity changed?
Explain why!
3. Based on the structure, point out how to convert the organic polymer into a conductive organic polymer!
Sub-Modeling skill 3
Using structure model to predict properties on the material
Sub-Modeling skill 3
solar cell, Dye-Sensitized Solar Cell (DSSC)
Polyacetylene as prototypes of conductive polymers
Polyaniline used in chemical sensors
especially for gases, electrochromic devices,
polymer LEDs
Students task using Student Spartan V6
Percentage of students who completed the task
Percentage of students who didn’t complete the task
Drawing the structure compound
83% 17%
Analyze the stability of compound
72% 28%
Analyze the stability based on isomer geometry
39% 61%
Analyze the stability based on conformation
33% 67%
Based on the minimize energy of the compound
Analyze the stability based on isomer geometry
Analyze the stability of conformers
Show the real imagine of chemical reaction
Predict and create the synthesis a new drug compound,
Create a new and available pathways of the
synthesis organic compound.
Modeling skills give chalenges to develop students’
need
Modeling skills in Chemistry learning to enhanche students HOTS in solving crucial problem in their life of 4.0 IR
Modeling skills make students select abundance information to make good decision
